Chrome Moly 4130 Motor Mounts - Prefab Parts?

[TansAir]

Hello all!!

I am currently building custom motor mounts for my 503 on custom UL. It has been been pretty straight forward so far, but I am stuck on the fabrication of some support uprights. I am using chrome moly 4130 tubes, and wish to join them up top by using same method common to that of most firewall mounts. I have attached picture to show the method I would like to reproduce for my application.

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I will likely use AN4 or AN5 bolts, and need to fabricate the bushing piece with round foot plate (sorry if my terminology is not accurate, but you get the idea). I was wondering if there is source for these small assemblies already produced? Then I can just attach and TIG my tubes and save some time. I checked leading edge, aircraft spruce, cannot find anything. They seem so common I figured there must be a supplier for them ... if anybody knows source please let me know.

Alternately, I have all the machine tools to make them, I find 4130 at mcmaster and can make the bushing from solid 4130. Their stndard tubing does not seem to have thick enough wall for this so I expect I would need to make from solid rod and bore out center on lath, no biggie. The round foot plate got me scratching my head tho, I cannot find discs or washers from 4130 (and of course I want to stay with same metals for TIG welding). I cannot image slicing such thin discs (from round bar) on the band saw for them, and likewise cannot image cutting circles from sheet metal either. Maybe a small hole saw and cut from sheet? There must be a better way or source for them??

Thanks in advance for any help or guidance on this one :D:thumbsup: Kevin

[TansAir]

... FYI: I am using ER70S-2 filler when I TIG the 4130 tubes, maybe there is compatible steel I can join with same filler, and that might open the door to other available already made parts (the bushings and maybe fender washers) that can be used for this? So that makes another question, are those small assemblies commonly made from "other than chrome moly"? Thanks!! Kevin

[martymayes]

I have made some of those before!! .....std tubing for the tube part. For example, 1/2" cm tubing has at least 8 std wall thicknesses from .028" to 1/8". Try shopping at one of the aircraft suppliers for more variety.

For the "washer" part, rough cut out of plate, drill hole, stack up on arbor, put arbor in lathe, turn OD to size, bazinga! Done.

[pshadwick]

I cut the small round circles using 4130 1/8" thick using a good hole saw on a drill press.
You can get 4130 tube in all sorts of wall thickness from Aircraft Spruce (and others). Weld them together and you are ready go :)
...Paul

[TansAir]

I have made some of those before!! .....std tubing for the tube part. For example, 1/2" cm tubing has at least 8 std wall thicknesses from .028" to 1/8". Try shopping at one of the aircraft suppliers for more variety.

For the "washer" part, rough cut out of plate, drill hole, stack up on arbor, put arbor in lathe, turn OD to size, bazinga! Done.

Awesome!! I like the idea of "stacking" the rough pieces and doing them all on lathe at once, that would save time, NICE!! Thanks!!

[TansAir]

I cut the small round circles using 4130 1/8" thick using a good hole saw on a drill press.
You can get 4130 tube in all sorts of wall thickness from Aircraft Spruce (and others). Weld them together and you are ready go :)
...Paul

If I go this route, I better upgrade my hole saws from Harbor Freight (they cannot even cut aluminum, LOL). Good idea on the tube or bushings from Aircraft Spruce tube (or others) ... that would be one less thing to mess with if I can avoid producing from rod or round bar!! Thanks a Bunch!!

[Bill Berson]

... FYI: I am using ER70S-2 filler when I TIG the 4130 tubes, maybe there is compatible steel I can join with same filler, and that might open the door to other available already made parts (the bushings and maybe fender washers) that can be used for this? So that makes another question, are those small assemblies commonly made from "other than chrome moly"? Thanks!! Kevin
Yes, common washers are used. Thicker is better for welding. Don't use or weld galvanized washers.

[TansAir]

Yes, common washers are used. Thicker is better for welding. Don't use or weld galvanized washers.

Thanks Bill!! Definitely no galvanized welding here, I think after first attempt we never forget what happens when trying, it's like welding without shield gas (a spattery mess) and dissimilar metals not good either. I stuck with the 4130 :cool:

[TansAir]

All done, and Thanks all for the helpful comments and suggestions!!


I used the 4130 sheet to make the "washer". It was overkill with the .125" thickness, I should have just used .065" and it would have been fine, eh well.

McMaster had nice hole saw, I went over size a little so that the resulting inner disk that drops out when done was closer to the 1.5" OD I wanted. The pilot drill was of course smaller that the 1/2" ID hole I needed, but easy to drill that out afterwards.

I found the 4310 tube from ACS, .5"OD x .120 wall, .26" ID.

Thanks to my trusty old Harbor Freight mill I was able to easily back drill (mill) thru the washer (after alignment by hand, with drill/mill not running). This made perfect fit for the 1/2" 4130 bushing.

I made quick holding fixture from scrap 2x2 alum channel, then tack welded first, final welding later.

Welding was done on my little HTP america TIG invertig welder (I love that little work horse). I used 100% argon shielding gas, and filler rod was ER70S-2.


Enjoy the pics, maybe others can benefit so I share .. Thanks again guys!! Kevin

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[lathropdad]

I find you approach to this problem interesting. I did the same type mounting but I started with the tube and the washer welded together. After welding the tube and washer, I trued the mounting surface of mount on the lathe. I think it is important to have the matting surface as flat as possible on the finished product.

Your approach makes a very nice looking part.

[Martyfeehan]

What settings are you using on your TIG for the tub welding? I have been trying to build an enbine mount and my practice welding is not very good.
Thanks,
Marty

[cub builder]

The washers are also commercially available from Aircraft Spruce at this link (https://www.aircraftspruce.com/catalog/eppages/enginemountwashers.php?clickkey=3009266). Select Q&A under the part to get the specs on the two versions they sell. I use the washers and 4130 tubing of the correct spec to fit the bolts.

-Cub Builder

[Aaron Novak]

All done, and Thanks all for the helpful comments and suggestions!!


I used the 4130 sheet to make the "washer". It was overkill with the .125" thickness, I should have just used .065" and it would have been fine, eh well.

McMaster had nice hole saw, I went over size a little so that the resulting inner disk that drops out when done was closer to the 1.5" OD I wanted. The pilot drill was of course smaller that the 1/2" ID hole I needed, but easy to drill that out afterwards.

I found the 4310 tube from ACS, .5"OD x .120 wall, .26" ID.

Thanks to my trusty old Harbor Freight mill I was able to easily back drill (mill) thru the washer (after alignment by hand, with drill/mill not running). This made perfect fit for the 1/2" 4130 bushing.

I made quick holding fixture from scrap 2x2 alum channel, then tack welded first, final welding later.

Welding was done on my little HTP america TIG invertig welder (I love that little work horse). I used 100% argon shielding gas, and filler rod was ER70S-2.


Enjoy the pics, maybe others can benefit so I share .. Thanks again guys!! Kevin

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Ok, I was trying to figure out a positive way to say this, but instead I am just going to be blunt. That welding job scares me. The penetration is non-existent, the welds are not complete, and the heat input seems really erratic. The toes of some of those globs just are horrid. It looks like you were using away too little heat input. I would really really suggest you do some more practice, have you work inspected by someone competent and then re-do those parts. The design is good, however the execution I would not pass. Please realize I am saying this not to be mean, but instead as someone concerned for your safety. I would love to help you improve your welding skills if you need some pointers etc.

[Bill Berson]

Looks like the bolt bushings are too thick. Makes it hard to get penatration of the thick bushing without blowing through the thin tube.

[Aaron Novak]

The thickness is not helping for sure, however with proper procedure and practice it could be done. The biggest error I see in hobbyist tig welding is lack of penetration. There is so much fear of burning through that they end with with these tiny looking welding sitting on top of the material, and the tig process by nature allows it.

[Bill Berson]

Yes, the warnings about TIG penetration are in AC-43.13.
The perfect fit up isn't needed or desired either.
A gap that allows correct penetration is recommended.

[Aaron Novak]

Yes, the warnings about TIG penetration are in AC-43.13.
The perfect fit up isn't needed or desired either.
A gap that allows correct penetration is recommended.

Oh for sure, that is standard practice in industry. Unfortunately there are some jokers that tell you to fit things up tight and use tiny welds, even though that goes against AWS specs , 43.13, the mechanics handbooks, etc, etc.

[cwilliamrose]

Yes, the warnings about TIG penetration are in AC-43.13.
The perfect fit up isn't needed or desired either.
A gap that allows correct penetration is recommended.

The other side of this is that gaps leave an exposed edge which the welder may try to protect by using less than sufficient heat. The weld gets wider because there's a gap to bridge but the penetration is not improved, it only looks that way because of the filler coming through the gap on the back side of the mating tube. The penetration on the 'main' tube (for example the longeron) is not enhanced in any way due to the gap being filled. The only way to get good penetration on both parts is to use the proper amount of current and good technique. Machine setup, tungsten grind, etc all play a role as well. Simply providing a gap does not insure a good result but can and usually does create more distortion in the finished weldment. There are no shortcuts to good welds and tight fits do not cause poor welds.

I agree that the bushing used in this mount is too thick walled and that extra metal serves no purpose. Getting enough heat into that bushing while dealing with a poor fit would be quite difficult.

[Aaron Novak]

The other side of this is that gaps leave an exposed edge which the welder may try to protect by using less than sufficient heat. The weld gets wider because there's a gap to bridge but the penetration is not improved, it only looks that way because of the filler coming through the gap on the back side of the mating tube. The penetration on the 'main' tube (for example the longeron) is not enhanced in any way due to the gap being filled. The only way to get good penetration on both parts is to use the proper amount of current and good technique. Machine setup, tungsten grind, etc all play a role as well. Simply providing a gap does not insure a good result but can and usually does create more distortion in the finished weldment. There are no shortcuts to good welds and tight fits do not cause poor welds.

I agree that the bushing used in this mount is too thick walled and that extra metal serves no purpose. Getting enough heat into that bushing while dealing with a poor fit would be quite difficult.

Part of the purpose of the gap on butt type welds is to provide some gas coverage into the joint itself. It also allows the arc to reach between the two parts, something it cannot do when fitted up tightly. If gas welding the gap allows the heat to travel between the two parts. AWS D17.1 specifies the gap to use, FAA as well. Industry uses gapping. While it itself is not the root cause of this particular issue, it is by far the best practice.

[cwilliamrose]

I don't have access to AWS documents. I quick look at 43.13 did not lead me to anything describing gaps in anything other than sleeved repairs. I will say the thought of the arc going into the gap between parts or the argon flowing into the cluster, displacing the air and shielding the back side of weld seems unlikely at best.

[Aaron Novak]

Well, unfortunately it is all copyrighted otherwise I would scan and post the documents here. The gap does indeed help quite a lot in forming 100% penetration weldments, although it does make welding seem more difficult for the novice, which is what I believe welding machine companies push it.

[cwilliamrose]

I sure wish I understood this gap = better penetration thing. The tube that's most difficult to get penetration on is the one that continues through the cluster and the gap does nothing for that one as far as I can tell. Brimm and Boggess says to use a 1/32" to 1/16" gap "depending on tube size" for expansion which doesn't ring true -- welding causes things to shrink, not expand. Of course that was written when gas welding was the most common method but still......

I'll continue doing what I've been doing for the last 40 years until I understand how an on purpose gap helps the integrity of the joint.

[Bill Berson]

It isn't about tube size, but rather the gap is dependent on thickness. Or if it can be welded on both sides or if only one side is accessible. Gap is an alternative to v grinding for full penatration in one pass. For example two 1/16" plates edge welded should probably have a 1/16" gap. Two 1/8" plates about 1/8"gap or if thicker use a V grind.
Don't normally need a gap for very thin tubing.
These are just my general comments. Every weld is different.

[Aaron Novak]

I sure wish I understood this gap = better penetration thing. The tube that's most difficult to get penetration on is the one that continues through the cluster and the gap does nothing for that one as far as I can tell. Brimm and Boggess says to use a 1/32" to 1/16" gap "depending on tube size" for expansion which doesn't ring true -- welding causes things to shrink, not expand. Of course that was written when gas welding was the most common method but still......

I'll continue doing what I've been doing for the last 40 years until I understand how an on purpose gap helps the integrity of the joint.

It was never for expansion, but actually it does help with contraction and "locked up" stresses. Although many times to the confusion of others, authors of welding texts will interchange the two. So tell me, when you are welding a cluster, are you doing keyhole welding?

[cwilliamrose]

I guess not since I had never heard that term before. I looked it up and I still don't know how that type of weld is accomplished. One source says "USING A STIFF. CONSTRICTED ARC" whatever that means.......

[Aaron Novak]

I guess not since I had never heard that term before. I looked it up and I still don't know how that type of weld is accomplished. One source says "USING A STIFF. CONSTRICTED ARC" whatever that means.......
Keyhole welding is you are using enough heat to cause the edges of the material to melt, pull back, and recombine on the back side of the weld pool. If you were to stop welding it would would like a keyhole sort of. When doing tubing work as in a cluster, the edge of the tube should pull up about 1-2x metal thickness and form a half keyhole. Otherwise think of it and simultaneously making and filling a hole, or half hole as you weld. 95% of the failed welds I cut apart look pretty, but are in fact just fillets sitting on top of the tube. Oh as a stuff constricted arc is formed by ( in the tig world ) a fairly blunt tungsten grind, high amperage and moving quickly.

[cwilliamrose]

Interesting. I use a pretty pointed grind, more like a regular sharpened pencil than a golf pencil. I don't weld fast when doing clusters for several reasons mostly having to do with having to start and stop a lot to change positions. I don't weld super fast when access is more open either. I see guys on YouTube really moving fast but that's not something I'd be successful with, even when I was younger and could see the puddle better.

I wonder what a cluster weld would look like when you stop like the image in post 26? There's generally only one edge and with my normal fits there's little if any gap. I should play with that and see what I learn.

[Aaron Novak]

Interesting. I use a pretty pointed grind, more like a regular sharpened pencil than a golf pencil. I don't weld fast when doing clusters for several reasons mostly having to do with having to start and stop a lot to change positions. I don't weld super fast when access is more open either. I see guys on YouTube really moving fast but that's not something I'd be successful with, even when I was younger and could see the puddle better.

I wonder what a cluster weld would look like when you stop like the image in post 26? There's generally only one edge and with my normal fits there's little if any gap. I should play with that and see what I learn.


Oh I know what you mean! One of the disadvantages of tig on 4130 is that every stop/start usually has some areas of the HAZ that are really hard, yet when welding a cluster man its difficult to keep moving. I know before I do something critical I will weld up a bunch of samples, section, polish and etch them to check for penetration etc. Even after all these years I still like to double check myself and improve with every project. We all have room to improve :)

[nixrox]

Hi: I am an aircraft mechanic and certified Non Destructive Testing Specialist (x-ray weld Inspector) with 40 years of experience. I don't usually comment on forums like this, unless I see a problem that is personal safety related. In the case outlined here 'welding an aircraft engine mount' - unless you are a certified AIRCRAFT welding specialist (either AWS or CWB), you should not be welding any LIFE CRITICAL components. You could be risking not only your life, but any passengers, or innocent bystanders on the ground, when you fall out of the sky. If you intend to continue with this folly, at least go out and buy the best Ballistic Recovery Parachute you can find, plus no passengers and no flying over populated areas.

Every certified aircraft engine mount was designed by an aeronautical engineer, a welding engineer, as well as a level 3 welding inspector. Each has a specific area of expertise. It starts with the computer design and testing of the mount and they will use stress analysis to make sure there are no weak spots in their design. Then a welding jig will be designed and built by the welding engineer and level 3 weld inspector, as well as the weld procedures, which a certified aircraft welder will follow to the letter. The procedure outlines the specific filler rod, the amperage settings, the speed and angle of the welding process etc etc etc. It follows with dozens of trial and error tests to make sure the welds will hold in the most impossible situations you can imagine. All this preparation before they even begin to weld the mount.

Welding is never as easy as it looks, especially on LIFE CRITICAL components. My recommendation - find a certified aircraft welder, who has extensive hands-on experience with this exact type of welding, as well as an approved weld procedure and welding jig. It does not matter how much it costs, if the end result is you do not kill yourself or others. OR the BRS is your last resort. I worked for two years in a helicopter search & rescue squadron - I carried more than my fair share of body bags.

[Sam Buchanan]

Hi: I am an aircraft mechanic and certified Non Destructive Testing Specialist (x-ray weld Inspector) with 40 years of experience. I don't usually comment on forums like this, unless I see a problem that is personal safety related. In the case outlined here 'welding an aircraft engine mount' - unless you are a certified AIRCRAFT welding specialist (either AWS or CWB), you should not be welding any LIFE CRITICAL components. You could be risking not only your life, but any passengers, or innocent bystanders on the ground, when you fall out of the sky. If you intend to continue with this folly, at least go out and buy the best Ballistic Recovery Parachute you can find, plus no passengers and no flying over populated areas.

Every certified aircraft engine mount was designed by an aeronautical engineer, a welding engineer, as well as a level 3 welding inspector. Each has a specific area of expertise. It starts with the computer design and testing of the mount and they will use stress analysis to make sure there are no weak spots in their design. Then a welding jig will be designed and built by the welding engineer and level 3 weld inspector, as well as the weld procedures, which a certified aircraft welder will follow to the letter. The procedure outlines the specific filler rod, the amperage settings, the speed and angle of the welding process etc etc etc. It follows with dozens of trial and error tests to make sure the welds will hold in the most impossible situations you can imagine. All this preparation before they even begin to weld the mount.

Welding is never as easy as it looks, especially on LIFE CRITICAL components. My recommendation - find a certified aircraft welder, who has extensive hands-on experience with this exact type of welding, as well as an approved weld procedure and welding jig. It does not matter how much it costs, if the end result is you do not kill yourself or others. OR the BRS is your last resort. I worked for two years in a helicopter search & rescue squadron - I carried more than my fair share of body bags.

Thousands of welded experimental aircraft have been flown that were not built by certified aircraft welding specialists.......

I consider every weld on my aircraft to be life critical. :)

[cwilliamrose]

The homebuilding movement never would have happened (and we wouldn't be here discussing this) if the welding required a certification.

[Aaron Novak]

Hi: I am an aircraft mechanic and certified Non Destructive Testing Specialist (x-ray weld Inspector) with 40 years of experience. I don't usually comment on forums like this, unless I see a problem that is personal safety related. In the case outlined here 'welding an aircraft engine mount' - unless you are a certified AIRCRAFT welding specialist (either AWS or CWB), you should not be welding any LIFE CRITICAL components. You could be risking not only your life, but any passengers, or innocent bystanders on the ground, when you fall out of the sky. If you intend to continue with this folly, at least go out and buy the best Ballistic Recovery Parachute you can find, plus no passengers and no flying over populated areas.

Every certified aircraft engine mount was designed by an aeronautical engineer, a welding engineer, as well as a level 3 welding inspector. Each has a specific area of expertise. It starts with the computer design and testing of the mount and they will use stress analysis to make sure there are no weak spots in their design. Then a welding jig will be designed and built by the welding engineer and level 3 weld inspector, as well as the weld procedures, which a certified aircraft welder will follow to the letter. The procedure outlines the specific filler rod, the amperage settings, the speed and angle of the welding process etc etc etc. It follows with dozens of trial and error tests to make sure the welds will hold in the most impossible situations you can imagine. All this preparation before they even begin to weld the mount.

Welding is never as easy as it looks, especially on LIFE CRITICAL components. My recommendation - find a certified aircraft welder, who has extensive hands-on experience with this exact type of welding, as well as an approved weld procedure and welding jig. It does not matter how much it costs, if the end result is you do not kill yourself or others. OR the BRS is your last resort. I worked for two years in a helicopter search & rescue squadron - I carried more than my fair share of body bags.

I appreciate your input from a safety perspective, but I do have to disagree with you on a couple points. First off on engine mount design, considering the time period most GA aircraft were designed in, I doubt most were designed by an engineer. Most were designed by the designer/fab shop and later analysis was done for TC approval, and as they are really over designed it was never an issue. Now bigger AC and Military, oh you bet they had a team designing them. A lot of what you are talking of applies to new production, and if you look back in homebuilding, the homebuilders used to seem out info from the OEMS and learn as much as they could. Now is seems there is this attitude that being a homebuilder means they can ignore history and do whatever they want and it will be fine. As for being a certified welder.....im mixed on that. The AWS criteria is really just a copy and paste from the old Military and Civilian aircraft welding tests for being and airframe mechanic, back when they taught that. That being said the certification only covers whatever process they tested in. In reality what you need is to approach this with the right attitude, test and calibrate yourself and your equipment, and make the best decisions. In general I think homebuilders should be doing more engineering themselves, more analysis and more NDT type work instead of treating what they are building as a "hot rod" with wings.

[BoKu]

Hi: I am an aircraft mechanic and [blah blah blah]...

Trebuchet ride!

[Aaron Novak]

Trebuchet ride!???

[BoKu]

???

Added to Ignore list:

1. Click username to view their profile.

2. Click Add to Ignore list.

3. Click Yes to confirm.

[Aaron Novak]

Added to Ignore list:

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Wow.......

[nixrox]

The homebuilding movement never would have happened (and we wouldn't be here discussing this) if the welding required a certification.

That is the reason so many pilots have ended up dead. Murphy's Law - if it can happen it will.

So if you are not a professional journeyman welder, EVERY weld you complete is marginal at best and blind luck if it holds.
Transport Canada dictates what welding is acceptable for an aircraft and so far everything I have seen says NO DEFECTS ALLOWED - none, zero, zip, nada.

If you have never taken any welding training courses, how can you guarantee that you used:
1. A proven weld procedure, the proper amperage settings and the proper welding or filler rod, whether MIG, TIG or STICK may have been the better choice
2. the proper metal stock that comes with the original chemical composition forms from the manufacturer
3. maybe the composition of the filler rod and the metal required you to preheat the base material before commencing welding and post welding heat to reduce HAZ cracking.
4. The welding you carried out might have required it to be stress relieved - which is a very long gradual heat reduction to reduce cracking
5. the list is endless and the potential defects are limitless

Which is why I have rejected thousands of welds and in several cases pushed welding companies into bankruptcy - because they could not weld to aircraft standards.

So once again - if you weld any parts on an aircraft and your are not certified as an aircraft welder - PLEASE do not take any passengers on your aircraft and never fly over a populated area. PLUS always fly with one hand on the BRS.

Have a nice day

[jim_p]

Seems a little over the top.

Do you have any actual data from the extensive FAA crash reports that backs up your alarming claims? Sounds like there should be quite a few documented cases of E-AB planes crashing due to failures of bad welds. I don’t doubt that it has happened, but I don’t recall it being in any of the lists of reasons for E-AB fatalities that the EAA, FAA, kit mfrs, and others have been working on diligently.

If you want to help people, educate them on the risks and proper procedures. Don’t come in and call everyone incompetent idiots if you want to be taken seriously.

[nixrox]

Like I said at the start of this - I never reply on these kinds of forums because I learned a long time ago that it is difficult to educate someone who thinks they know everything already - which has been clearly demonstrated by the above responses.
I see a number of glaring problems that are safety related and I express my opinion - if the people who read this forum reject my opinions (which are based on actual hands-on experience) I don't really care.
If they want to risk their own lives - I don't really care.
It is when they involve others - that is when it bothers me.

One last comment to the individuals who are TIG welding 4130 steel tubing - If you are not adding shielding gas (argon) to the inside of the tube in the same amount as the front side - I can pretty well guarantee 100 percent - there are a number of of oxygen induced defects in your welds. They will be full of porosity.

Which is why I intend to bring this matter forward to Transport Canada.
If you want to build an aircraft and you weld it yourself without any welder training or x-rays to prove the quality of the welds - then you should never be able to sell the aircraft, or carry passengers, or fly over populated areas.
If you want to commit suicide - knock yourself out - just don't take anyone else with you.

Twenty five years ago, I was asked by a friend of mine to x-ray the door frame tubing of a old Piper Cub he was considering purchasing. I found visual evidence of severe corrosion. To demonstrate - I took a ball point pen and was able to push it right through the tube at the worst area. How many people do you know have ever taken the time, when they are rebuilding an antique aircraft, to take a few x-rays of critical areas. That was the only time in my career and my friend did not buy that aircraft and no I did not charge him for the x-ray film.

[cwilliamrose]

Surprise surprise, no data to back up the panic.

[rwanttaja]

Do you have any actual data from the extensive FAA crash reports that backs up your alarming claims? Sounds like there should be quite a few documented cases of E-AB planes crashing due to failures of bad welds. I don’t doubt that it has happened, but I don’t recall it being in any of the lists of reasons for E-AB fatalities that the EAA, FAA, kit mfrs, and others have been working on diligently.
I did a search on the NTSB database, for aircraft flagged as homebuilt in which the word "weld" is mentioned in the Probable Cause. I found eighteen cases from 1998 to 2016, roughly one per year. Three resulted in fatalities.

http://www.wanttaja.com/weld_failures.pdf

Ron Wanttaja

[cwilliamrose]

Thanks Ron,

Not many in 18 years, certainly short of an epidemic we need to remedy with draconian measures.

[nixrox]

How many more than ONE do you need - before you consider this a problem. Now you see that three (3) fatalities are on file.
I have spent 40 years as an NDT specialist and teacher.
I have taught more than 2500 people everything I know about Non Destructive Testing and how it affects every facet of our industrial life.
In all these years, we have been behind the curve when it comes to mechanical failures.
Very rarely do we ever get the chance to find a defect and then go out to all the similar aircraft types to search for possible defects.
99% of the time we are called in after an aircraft part has failed and someone has died.

I thought my concerns regarding welding defects could be used as a preventative cautionary warning that might keep at least one person alive.
Well I tried - I am no longer interested in this discussion.
Have a nice day.

[Sam Buchanan]

Wow........I bet Transport Canada can hardly wait........ ;)

Concern for safety of builders and pilots is certainly prudent, but inferring that everyone who has built an aircraft without "certification" is a danger to society is over the top. A much more reasonable approach would lead to more credibility.

[cwilliamrose]

I count two. The third was the result of the pilot not terminating the flight when told of a problem with the airplane. That's two in almost twenty years. I'm OK with that, not happy but OK.

Stuff happens with metal construction, wood, composites. Crying wolf doesn't help. I'm done too......

[jim_p]

Thanks Ron and cwilliamrose for looking up the actual data. 2 is too many of course but way down on the list of things to worry about according to the actual data. So either non-certified welders aren’t complete disasters, or the parts are over engineered in general, or people are taking the welding jobs to experts more than we know.

Of course, if someone who was a good welder (certified or not) wanted to help teach and share expertise and things to be careful of, in a civil, even friendly and cheerful manner, that would be great. Might even make some friends, grow some skill sets, make planes safer, and save some planes and lives.

[emoji3]

[Aaron Novak]

Well this certainly got weird fast. The thing is I get where nixrox is coming from, as I work in NDT and materials as well, however there has to be a dose of reality there as I also work in prototyping where you don't have the advantage of making 100 identical parts to study and fine tune a process and procedure. We get one shot to do it. This is why I have preached using the most conservative approach to constructing any one of part. Is there shoddy welding in some homebuilts....honestly yes. Are there failed welds both OEM and homebuilt.....yes. Luckily most are caught and the designs robust enough to survive to repair so nobody hears about them. Should we rely on this robustness alone....absolutely not. There is room for education and improvement in the homebuilt area and the EAA is in an excellent position to do so, if they should ever choose.

[nixrox]

Well this certainly got weird fast. The thing is I get where nixrox is coming from, as I work in NDT and materials as well, however there has to be a dose of reality there as I also work in prototyping where you don't have the advantage of making 100 identical parts to study and fine tune a process and procedure. We get one shot to do it. This is why I have preached using the most conservative approach to constructing any one of part. Is there shoddy welding in some homebuilts....honestly yes. Are there failed welds both OEM and homebuilt.....yes. Luckily most are caught and the designs robust enough to survive to repair so nobody hears about them. Should we rely on this robustness alone....absolutely not. There is room for education and improvement in the homebuilt area and the EAA is in an excellent position to do so, if they should ever choose.

Aaron - do you have any x-ray film to prove that your welds are defect free? How about Ultrasonic weld inspection reports by a certified UT Tech? How many CGSB or ASNT level 2 or 3 certifications do you hold?

You cannot weld on certified aircraft without a license.
You cannot fly an aircraft without a license.
You cannot perform maintenance on a certified aircraft without a license.
You cannot perform NDT inspections on aircraft without a license.
You cannot weld anything in the oil or construction industry without a license and a successful welder test at the site.
What makes you think anyone should be allowed to weld on an aircraft without a license or any recognized training or testing?

Did you notice that not one of the sarcastic responding trolls or naysayers mentioned the EIGHTEEN (18) destroyed aircraft due specifically to weld problems since 1996.

I rest my case and will let Darwin's theory root out those individuals who like to tempt fate.
As a person with some NDT knowledge, I would have expected you to have a better handle on defect propagation and structural analysis.
Good luck by the way.

[jim_p]

@nixrox Which part of “experimental - amateur built” is it that you don’t understand?

Experimental GA aircraft are pretty minimal for what they have to do. Most of the parts of the plane are life critical. E-AB builders understand and accept that and make their own choices about what to buy, hire out, or do themselves. Your attitude of “only the pros should ever do that” is pretty much the opposite of the whole point of E-AB.

Nobody is taking you very seriously because you are barging in insulting everyone without offering anything to actually help people weld better. That’s the only way you are going to make a useful difference here.

[rwanttaja]

Did you notice that not one of the sarcastic responding trolls or naysayers mentioned the EIGHTEEN (18) destroyed aircraft due specifically to weld problems since 1996.
1998-2016, actually. That's just about one accident a year, or roughly 0.5% (half a percent) of homebuilt accidents. Only three of them resulted in fatalities, accounting for 0.3% of the fatal accidents.

Not saying a reduction wouldn't be nice, it's just not a major contributor to the homebuilt accident rate. The same amount of effort to "fix" other problems would save more lives.

Here's a summary of the number of fatal accidents for given causes. This, again, covers the 1998-2016 time period. There were about 960 fatal accidents in this time period.


Accident Cause

Number of Fatal Accidents


Pilot Miscontrol

284


Manuevering Low Alt

116


Engine Failure - Undetermined

83


Continued VFR into IFR Conditions

38


Fuel Exhaustion

29


Midair

24


Pilot Incapacitation

20


Internal Engine Issues

18


Failure to Recover from Aerobatics

18


Fuel Starvation

12


CG or Weight

11


Fuel System Issues

10


Carb Ice

9


Fuel Contamination

8


Inadequate Preflight

7


Reduction Drives

6


Fire

6


Disorientation

5


Ignition

4


Carb Mechanical

4


Oil System

3


Cooling System

2


Wake Turbulence

2


Airframe Icing

2


Suicide

2


Note that there were almost as many accidents involving suicide as there were fatal accidents involving bad welds. As far as I can determine, the weld issues just aren't that common.

Mind you, bad welds only make the NTSB database if an accident meets the reporting criteria. Likely there were more failed welds, that either caused little or no damage or were detected on the ground prior to takeoff.

No one's doubting that homebuilt welds could be better, just that bad welds aren't that major a problem.

Ron Wanttaja

[Aaron Novak]

Aaron - do you have any x-ray film to prove that your welds are defect free? How about Ultrasonic weld inspection reports by a certified UT Tech? How many CGSB or ASNT level 2 or 3 certifications do you hold? I have done X-ray yes, Ultrasonic yes, I don't live in Canada.

You cannot weld on certified aircraft without a license. Here in the USA yes you can, you just cannot sign it off.
You cannot fly an aircraft without a license. The OP is working on an ultralight, so yes he can.
You cannot perform maintenance on a certified aircraft without a license. Unless you are the builder or it is an ultralight true. Or if you are working under someone with the proper credentials.
You cannot perform NDT inspections on aircraft without a license. Again, in the homebuilt world yes you can, and even in the certified world anyone can do the work as long as a person with the proper credentials signs it off.
You cannot weld anything in the oil or construction industry without a license and a successful welder test at the site. That is because the weldors self certify each weldment, and much of the history of pipeline welding is linked to unions and having to hold union "tickets" etc etc. Not that pipelines ever have failed welds.....
What makes you think anyone should be allowed to weld on an aircraft without a license or any recognized training or testing? That's not up to me, that is up to the FAA, and they don't exclude anyone.

Did you notice that not one of the sarcastic responding trolls or naysayers mentioned the EIGHTEEN (18) destroyed aircraft due specifically to weld problems since 1996. Are we counting the ones caused by the design and production engineers improper welding processes and procedures?

I rest my case and will let Darwin's theory root out those individuals who like to tempt fate.
As a person with some NDT knowledge, I would have expected you to have a better handle on defect propagation and structural analysis.
Good luck by the way. The majority of the failures I see are fatigue initiating in the microstructure of the HAZ, nothing that can be found with NDT, and that is why my efforts have concentrated on best practices from a design and welding process perspective. The reinforcement sizes of proper welds on 4130 tubular structures are so oversize ( a good thing) that even large oxide inclusions seem to pose little threat. See above for my comments.

Just for clarification, you were an inspector, not a weldor correct? I see in your list of tools that you have mig welders and a stick welder, so I am guessing you yourself do not do, or teach aerospace welding? Just trying to get an idea what your experience level and type is?

[rick9mjn]

to add my small idea the forum. maybe the welder could cut into some of his welds , one poor weld ,one good weld , and one of his best welds. To see how to see his welding / heating penetrates the metal.........and on seeing photos ,the original poster. is using, some nice jigs / fixtures ..... good day /// rick

[nixrox]

Well you guys certainly are extremely sensitive and very easy to get a rise out of.
However, in the interests of clearing the air, I decided to go straight to the horses mouth - Miller Welding.
I found an article that covers best practices for welding 4130 chrome-moly, low alloy tubing.
Surprise, surprise - if you follow this article carefully, you should notice that the 'novice' home built welders on this forum have been giving you totally wrong information.
So if you want the correct information you need to go to the specialist who actually do this for a living.
Enjoy the article.


Best Practices for TIG Welding of 4130 Chrome-Moly Tubing
In General Motorsports and Aerospace Applications


Chrome-moly steel offers a good blend of strength, weight and ductility
for many motorsports and aerospace applications. The following article
discusses some of the recommended procedures and equipment for
successfully TIG welding 4130 chrome-moly steel.


Just as a NHRA (National Hot Rod Association) drag racing team depends
on blend of team talent to win races, the material selected for a
particular application requires a blend of properties to withstand the
stresses involved. For a drag racing chassis, and for many other
motorsports and aerospace applications, that material is 4130
chromium-molybdenum, or chrome-moly, which is selected for its blend of
ductility, strength, weight and fabrication advantages.

The 4130 grade of chrome-moly is a high-strength low-alloy (HSLA) steel
that contains molybdenum (0.15 - 0.25 percent by weight) and chromium
(0.8 - 1.1 percent by weight) as strengthening agents. However, it has
relatively low carbon content (nominally 0.30 percent), so it welds,
machines and bends almost as easily as 1018 DOM mild steel tubing (which
has an 0.18 percent carbon content).


*Material* *Tensile Strength* *Yield Strength *Hardness, Rockwell B* *Elongation*
4130 chrome-moly 97,200 psi 63,100 psi 92 25.5%


Chrome-moly is not lighter than steel, a common misconception. Both
weigh about 491 lbs. per cubic foot.
However, chrome-moly offers a better strength-to-weight ratio and better
elongation (a measure of ductility), which enables designers to use
thinner wall and/or smaller diameter tubing to reduce overall weight.

Because many motorsports, aerospace and sporting goods applications
involve welding normalized 4130 chrome-moly tubing with a wall
thicknesses of less than .125-in., this article will focus on best
practices for these applications.

Welding Consumables and Variables

Material 4130 chrome-moly tubing (normalized).

Thickness < 0.125 in. Most chassis tubing has a wall thickness ranging
from 0.035 – 0.083 in. and diameters from 1/4in. - 1-5/8in.

Amperage 1 amp per .001 in. of wall thickness.

Polarity DC Electrode Negative. HF for arc starts only.

Pulsing Optional.

Filler Material ER70S-2 or ER80S-D2.

Filler Diameter 0.030 – 1/8-in. Generally, do not use a rod larger than the thickness of the base metal.

Tungsten Type 2% type (Ceriated is first choice, then Thoriated)

Tungsten Diameter 1/16 – 3/32 (smaller diameter for thinner wall).

Tungsten Prep Pointed.

Arc Length
Less than or equal to the electrode diameter. Generally, the tighter
the better, as shorter arc lengths reduce heat input.

Electrode Stickout
No further than the distance of the inside diameter
of the cup being used. However using a gas lens can extend this distance.
Gas Lens Not required, but helpful if a tight joint configuration
demands a longer stickout or involves multiple tubes. Keep the screen
free of debris and spatter.

Shielding Gas
100% argon, 15 – 20 CFH. More is not better, as
turbulence could suck atmosphere into the weld.

Pre-flow
.4 to .6 seconds.

Post-flow
10 – 15 seconds.

Backing Gas
Follow applicable codes/standards, if any; not required for NHRA applications.
It is required for aircraft to reduce potetial contamination on the backside of the weld.

Pre-heat
Not required as long as tubing is above 60 – 70 degrees F.

Stress Relief
Not required on material < 0.125 inch; simply allow the weld to air-cool.

Tack Welds
Four tacks made 90 degrees apart; tacks ideally should be longer than wide.

Joint Preparation
Tubing notcher for coping, drum sander for final
fit-up, deburring for edge preparation, Scotch-Brite™ or 120 grit sand
paper to clean about 1 in. back from the joint, and final clean with
acetone, lacquer thinner or similar solvent to remove oil.

Joint Gap
None! Realistically, gaps smaller than 0.010 are permissible; larger
gaps promote poor quality.

Weld Size
Keep welds to within their specified size: a weld needs to be no larger
than its thinnest section, which will be the “weakest link” in the
chain. Larger-than-necessary welds add excess heat and waste gas, filler
rod and time.

Weld Technique
Weld in one continuous motion, pulsing the foot control
and adding filler rod to create the “stack of dimes” appearance (or use
the machine’s pulsing controls). Do not stack separate puddles on top of
each other, as this may lead to incomplete fusion.

End-of-Weld Procedure
Avoid pinholes by tapering off heat input at the end of the weld and
maintaining a constant distance between the tungsten and the weldment.

Weld Appearance
A good weld looks shiny and has a bluish tint. A dirty, gray-looking
weld may indicate poor shielding gas coverage or excess heat.


Perfect Fit-Up

When welding thin-wall tubing, whether chrome-moly or other metals, the
welders at Cagnazzi Racing joke that their tolerances range from perfect
to almost not perfect. That is, if the parts don’t fit perfectly, they
start over because thin-wall tubing does not have sufficient mass to
absorb excess heat.

The usual “trick” to filling gaps with GTAW is to use a larger diameter
filler rod. However, larger rods require more heat and excess heat
promotes burn-through, warping and embrittlement. Using a larger rod
might be an acceptable solution in a non-critical application, but it’s
a poor practice when welding chrome-moly.

Consistency
Cagnazzi uses hundreds of jigs and fixtures bolted to a surface that is
flat to within a few thousandths of an inch for fabricating even the
smallest items to help ensure tight fit-up and consistent tube
placement, which provides repeatability

Chrome Moly Tubing Consistency
By producing a new chassis nearly identical to the previous, the crew
chief can hone his craft of gear ratio and clutch management without
worrying about a new chassis introducing unknown variables. Many
fabricators believe that they cannot afford to build fixtures for all of
their components or for larger weldments. However, if repeatability and
accuracy are important, good fixturing is mandatory.


Coping Mechanism
Most of Cagnazzi’s jigs have a go/no-go type fit, which enables
“sneaking up” on a perfect fit by making small incremental adjustments.

After cutting to approximate length with a band saw, Cagnazzi uses a
tube notcher for rough coping. The fabricator will then check
the length and use a drum sander to sneak up on a perfect fit by slowly
sanding away excess metal from the mouth of the tube. Before
welding, the fabricator will deburr the edge , clean back 1 in.
from edge using Scotch-Brite or 120 grit sandpaper and remove oils or
other contaminants with a solvent. Be sure to wear nitrile
gloves, as the natural oils from your fingers can ruin a weld just as
thoroughly as grease or cutting fluid. Don’t forget to use the sandpaper
and solvent on the filler rod, too.

Filler Metal Selection
In many motorsports and aerospace applications, engineers want some
degree of ductility in the weld to help absorb impacts and prevent
cracking. For this reason, most NHRA fabricators intentionally dilute
the strength of the parent material by selecting ER70S-2 for filler for
roll cages, chassis and other applications requiring more flexibility.
While actual tensile strength of the weld will vary and depend on other
factors, 4130 diluted with ER70S-2 filler likely produces a weld with a
tensile strength in the 80,000 to 82,000 psi range.

For areas requiring higher strength, such as spindles and upper and
lower control arms, fabricators select ER80S-D2 filler, which produces
welds with a high tensile strength (as a side note, consider that S-2
fillers clean impurities better than D-2 fillers). In any event, do not
use 4130 filler, as the weld will not have sufficient ductility unless
it undergoes stress relief.

As for filler rod diameter, use a rod diameter that matches the
thickness of the base metal. Trying to weld 0.035-in. tubing with a
1/16th inch filler (0.063-in.) is a bad idea because the tubing wall
will melt before the filler rod is up to temperature. Cagnazzi
predominantly uses 0.030-, 0.045- and 0.063-in. (1/16th) filler rods
, with .045 and .063 being the most common. For thicker, larger
diameter tubing they use 3/32- and 1/8-in. rods.

Heat Control
Successfully welding 4130 requires preserving its mechanical properties
by heating and cooling the weld in a controlled manner. Excess heat
causes carbide precipitation, and cooling too quickly causes
embrittlement. Fortunately, the GTAW process provides sufficient heat
control. Welds made on tubing 1/8-inch or thinner do not require
pre-heating or post-weld stress relief, yet they will have sufficient
penetration as long operators follow the general rule of the thumb by
using 1 amp per 0.001 in. of metal thickness.
Note that if the tubing is below 60 degrees F, use a small propone torch
to heat the base metal to up to 300 degrees F. Otherwise, the metal
could cool too quickly and become brittle. Welding cold metal may also
promote hydrogen cracking, so that’s another reason to preheat 4130 if
it’s cold.


Puddle Size and Arc Length
While welding too slowly increases overall heat input, operators should
not necessarily focus on welding travel speed. Rather, they should focus
on controlling their body (Fig. 11), controlling puddle size by making
the puddle only as wide as necessary and holding a tight arc length of
1/8-in. or less.

Note that a longer arc length, or tungsten tip-to-work distance,
increases overall heat input, because a GTAW power source automatically
increases voltage when arc length increases. If the joint configuration
limits access because of cup size, do not try to weld with a longer arc.
Rather, use a smaller cup or a gas lens and extend the tungsten.

To better control heat input, and to enable repositioning the body to
better control torch movement, do not weld the circumference of a tube
in one pass. Rather, weld it in four quarters. Weld only two of the
quarters (on opposite side of the tube) then move to another joint. When
the first joint cools, come back and complete the remaining sections.


No Slacking Allowed — EVER

The authors of this article weld 4130 tubing in critical applications,
and they have a combined 50 years of welding experience. As such, they
take every step of the fabrication process seriously.

“Close enough” is simply not good enough for NHRA or AEROSPACE work,
nor should it be, for a child’s go-kart or bicycle.

[Aaron Novak]

Well you guys certainly are extremely sensitive and very easy to get a rise out of.
However, in the interests of clearing the air, I decided to go straight to the horses mouth - Miller Welding.
I found an article that covers best practices for welding 4130 chrome-moly, low alloy tubing.
Surprise, surprise - if you follow this article carefully, you should notice that the 'novice' home built welders on this forum have been giving you totally wrong information.
So if you want the correct information you need to go to the specialist who actually do this for a living.
Enjoy the article.


Best Practices for TIG Welding of 4130 Chrome-Moly Tubing
In General Motorsports and Aerospace Applications


Chrome-moly steel offers a good blend of strength, weight and ductility
for many motorsports and aerospace applications. The following article
discusses some of the recommended procedures and equipment for
successfully TIG welding 4130 chrome-moly steel.


Just as a NHRA (National Hot Rod Association) drag racing team depends
on blend of team talent to win races, the material selected for a
particular application requires a blend of properties to withstand the
stresses involved. For a drag racing chassis, and for many other
motorsports and aerospace applications, that material is 4130
chromium-molybdenum, or chrome-moly, which is selected for its blend of
ductility, strength, weight and fabrication advantages.

The 4130 grade of chrome-moly is a high-strength low-alloy (HSLA) steel
that contains molybdenum (0.15 - 0.25 percent by weight) and chromium
(0.8 - 1.1 percent by weight) as strengthening agents. However, it has
relatively low carbon content (nominally 0.30 percent), so it welds,
machines and bends almost as easily as 1018 DOM mild steel tubing (which
has an 0.18 percent carbon content).


*Material* *Tensile Strength* *Yield Strength *Hardness, Rockwell B* *Elongation*
4130 chrome-moly 97,200 psi 63,100 psi 92 25.5%


Chrome-moly is not lighter than steel, a common misconception. Both
weigh about 491 lbs. per cubic foot.
However, chrome-moly offers a better strength-to-weight ratio and better
elongation (a measure of ductility), which enables designers to use
thinner wall and/or smaller diameter tubing to reduce overall weight.

Because many motorsports, aerospace and sporting goods applications
involve welding normalized 4130 chrome-moly tubing with a wall
thicknesses of less than .125-in., this article will focus on best
practices for these applications.

Welding Consumables and Variables

Material 4130 chrome-moly tubing (normalized).

Thickness < 0.125 in. Most chassis tubing has a wall thickness ranging
from 0.035 – 0.083 in. and diameters from 1/4in. - 1-5/8in.

Amperage 1 amp per .001 in. of wall thickness.

Polarity DC Electrode Negative. HF for arc starts only.

Pulsing Optional.

Filler Material ER70S-2 or ER80S-D2.

Filler Diameter 0.030 – 1/8-in. Generally, do not use a rod larger than the thickness of the base metal.

Tungsten Type 2% type (Ceriated is first choice, then Thoriated)

Tungsten Diameter 1/16 – 3/32 (smaller diameter for thinner wall).

Tungsten Prep Pointed.

Arc Length
Less than or equal to the electrode diameter. Generally, the tighter
the better, as shorter arc lengths reduce heat input.

Electrode Stickout
No further than the distance of the inside diameter
of the cup being used. However using a gas lens can extend this distance.
Gas Lens Not required, but helpful if a tight joint configuration
demands a longer stickout or involves multiple tubes. Keep the screen
free of debris and spatter.

Shielding Gas
100% argon, 15 – 20 CFH. More is not better, as
turbulence could suck atmosphere into the weld.

Pre-flow
.4 to .6 seconds.

Post-flow
10 – 15 seconds.

Backing Gas
Follow applicable codes/standards, if any; not required for NHRA applications.
It is required for aircraft to reduce potetial contamination on the backside of the weld.

Pre-heat
Not required as long as tubing is above 60 – 70 degrees F.

Stress Relief
Not required on material < 0.125 inch; simply allow the weld to air-cool.

Tack Welds
Four tacks made 90 degrees apart; tacks ideally should be longer than wide.

Joint Preparation
Tubing notcher for coping, drum sander for final
fit-up, deburring for edge preparation, Scotch-Brite™ or 120 grit sand
paper to clean about 1 in. back from the joint, and final clean with
acetone, lacquer thinner or similar solvent to remove oil.

Joint Gap
None! Realistically, gaps smaller than 0.010 are permissible; larger
gaps promote poor quality.

Weld Size
Keep welds to within their specified size: a weld needs to be no larger
than its thinnest section, which will be the “weakest link” in the
chain. Larger-than-necessary welds add excess heat and waste gas, filler
rod and time.

Weld Technique
Weld in one continuous motion, pulsing the foot control
and adding filler rod to create the “stack of dimes” appearance (or use
the machine’s pulsing controls). Do not stack separate puddles on top of
each other, as this may lead to incomplete fusion.

End-of-Weld Procedure
Avoid pinholes by tapering off heat input at the end of the weld and
maintaining a constant distance between the tungsten and the weldment.

Weld Appearance
A good weld looks shiny and has a bluish tint. A dirty, gray-looking
weld may indicate poor shielding gas coverage or excess heat.


Perfect Fit-Up

When welding thin-wall tubing, whether chrome-moly or other metals, the
welders at Cagnazzi Racing joke that their tolerances range from perfect
to almost not perfect. That is, if the parts don’t fit perfectly, they
start over because thin-wall tubing does not have sufficient mass to
absorb excess heat.

The usual “trick” to filling gaps with GTAW is to use a larger diameter
filler rod. However, larger rods require more heat and excess heat
promotes burn-through, warping and embrittlement. Using a larger rod
might be an acceptable solution in a non-critical application, but it’s
a poor practice when welding chrome-moly.

Consistency
Cagnazzi uses hundreds of jigs and fixtures bolted to a surface that is
flat to within a few thousandths of an inch for fabricating even the
smallest items to help ensure tight fit-up and consistent tube
placement, which provides repeatability

Chrome Moly Tubing Consistency
By producing a new chassis nearly identical to the previous, the crew
chief can hone his craft of gear ratio and clutch management without
worrying about a new chassis introducing unknown variables. Many
fabricators believe that they cannot afford to build fixtures for all of
their components or for larger weldments. However, if repeatability and
accuracy are important, good fixturing is mandatory.


Coping Mechanism
Most of Cagnazzi’s jigs have a go/no-go type fit, which enables
“sneaking up” on a perfect fit by making small incremental adjustments.

After cutting to approximate length with a band saw, Cagnazzi uses a
tube notcher for rough coping. The fabricator will then check
the length and use a drum sander to sneak up on a perfect fit by slowly
sanding away excess metal from the mouth of the tube. Before
welding, the fabricator will deburr the edge , clean back 1 in.
from edge using Scotch-Brite or 120 grit sandpaper and remove oils or
other contaminants with a solvent. Be sure to wear nitrile
gloves, as the natural oils from your fingers can ruin a weld just as
thoroughly as grease or cutting fluid. Don’t forget to use the sandpaper
and solvent on the filler rod, too.

Filler Metal Selection
In many motorsports and aerospace applications, engineers want some
degree of ductility in the weld to help absorb impacts and prevent
cracking. For this reason, most NHRA fabricators intentionally dilute
the strength of the parent material by selecting ER70S-2 for filler for
roll cages, chassis and other applications requiring more flexibility.
While actual tensile strength of the weld will vary and depend on other
factors, 4130 diluted with ER70S-2 filler likely produces a weld with a
tensile strength in the 80,000 to 82,000 psi range.

For areas requiring higher strength, such as spindles and upper and
lower control arms, fabricators select ER80S-D2 filler, which produces
welds with a high tensile strength (as a side note, consider that S-2
fillers clean impurities better than D-2 fillers). In any event, do not
use 4130 filler, as the weld will not have sufficient ductility unless
it undergoes stress relief.

As for filler rod diameter, use a rod diameter that matches the
thickness of the base metal. Trying to weld 0.035-in. tubing with a
1/16th inch filler (0.063-in.) is a bad idea because the tubing wall
will melt before the filler rod is up to temperature. Cagnazzi
predominantly uses 0.030-, 0.045- and 0.063-in. (1/16th) filler rods
, with .045 and .063 being the most common. For thicker, larger
diameter tubing they use 3/32- and 1/8-in. rods.

Heat Control
Successfully welding 4130 requires preserving its mechanical properties
by heating and cooling the weld in a controlled manner. Excess heat
causes carbide precipitation, and cooling too quickly causes
embrittlement. Fortunately, the GTAW process provides sufficient heat
control. Welds made on tubing 1/8-inch or thinner do not require
pre-heating or post-weld stress relief, yet they will have sufficient
penetration as long operators follow the general rule of the thumb by
using 1 amp per 0.001 in. of metal thickness.
Note that if the tubing is below 60 degrees F, use a small propone torch
to heat the base metal to up to 300 degrees F. Otherwise, the metal
could cool too quickly and become brittle. Welding cold metal may also
promote hydrogen cracking, so that’s another reason to preheat 4130 if
it’s cold.


Puddle Size and Arc Length
While welding too slowly increases overall heat input, operators should
not necessarily focus on welding travel speed. Rather, they should focus
on controlling their body (Fig. 11), controlling puddle size by making
the puddle only as wide as necessary and holding a tight arc length of
1/8-in. or less.

Note that a longer arc length, or tungsten tip-to-work distance,
increases overall heat input, because a GTAW power source automatically
increases voltage when arc length increases. If the joint configuration
limits access because of cup size, do not try to weld with a longer arc.
Rather, use a smaller cup or a gas lens and extend the tungsten.

To better control heat input, and to enable repositioning the body to
better control torch movement, do not weld the circumference of a tube
in one pass. Rather, weld it in four quarters. Weld only two of the
quarters (on opposite side of the tube) then move to another joint. When
the first joint cools, come back and complete the remaining sections.


No Slacking Allowed — EVER

The authors of this article weld 4130 tubing in critical applications,
and they have a combined 50 years of welding experience. As such, they
take every step of the fabrication process seriously.

“Close enough” is simply not good enough for NHRA or AEROSPACE work,
nor should it be, for a child’s go-kart or bicycle.

Miller is not an authority on aerospace weldments on 4130, they are a company that makes welding equipment ( To be fair NONE of the welding machine manufacturers should be considered design experts for weldments). They have no materials lab, no NDT lab, no MTS lab, do no structural or fatigue testing of any kind. This is not their job, they are not something like edison welding institute or southwest research or NASA, they are a tool maker. Their suggestions are kind of sketchy do you not agree? How can you use material thickness alone to determine if you need PWHT? No mention of joint configuration at all? It looks like they grabbed that thickness from what I am guessing is a jominy bar test and misunderstood the data or totally missed the material thickness equivalency calculations. This is not a bash on Miller at all, they are a fine company that I have visited many times. I'm really trying to figure out where you are going here? You claim nobody knows what they are doing in aviation, yet post a copy and paste off the internet from a company that has no authority in aviation. Considering your push to put engineering into weldments I am just surprised.

[nixrox]

obviously you have a reading handicap.
Miller never wrote the article - they just put it in the magazine.
The article was written by two journeyman welders with 50 years of experience.
I trust journeyman far more than part-time trainee welders - like you.

You should not be giving welding advice to anyone, because you do not have the license, training nor experience.
The difference between you and me is that I always take welding projects to journeyman welders.
I may be a certified weld inspector and licensed NDT Inspector but my welding sucks.
I complete all the mechanical work and farm out the welding and upholstery to the experts.
have a nice day.

[jim_p]

obviously you have a reading handicap.
Miller never wrote the article - they just put it in the magazine.
The article was written by two journeyman welders with 50 years of experience.
I trust journeyman far more than part-time trainee welders - like you.

You should not be giving welding advice to anyone, because you do not have the license, training nor experience.
The difference between you and me is that I always take welding projects to journeyman welders.
I may be a certified weld inspector and licensed NDT Inspector but my welding sucks.
I complete all the mechanical work and farm out the welding and upholstery to the experts.
have a nice day.

I don’t know why I try but here goes...

What was the point of insulting him? And where exactly did you give a link or cite for the text you posted? When I read your post I see no links, no author names, no dates, no magazine name, nothing but your assertion that Miller is your authoritative “from the horses mouth” source and what looks like you commentary at the end about the authors. What exactly is in your post that he could have read better?

The article itself, and even better a link to where everyone can see it in context, is the sort of thing you could have come in and posted along with some questions about what you saw, how it looked imperfect to you, and how it could be done better. The article is helpful. It is your condescending attitude that is keeping you from doing any good.

[nixrox]

Jim_P
I hate to admit this, but you are absolutely right. I have approached this subject from the wrong perspective. I failed to recognize that I have been dealing with individuals who are not fully cognizant of all the potential problems involved with welding processes, because they have no formal weld training. They don't know enough about welding, to realize they don't know enough and should not be welding critical aircraft structures. I forget that my original mechanic apprenticeship was four years long for a reason - there is just too much that can go wrong on an aircraft, if you are not fully aware all the things that can go wrong.

So I sincerely apologize to everyone for the way that I handled this subject. I hope that this entire conversation is not forgotten or discounted and that it does pass along the fact that welding is not easy. Welding critical aircraft structures should not be attempted by novice trainees unless they are under the direct supervision of a journeyman welder. Your life and the people you care about are much to precious to jeopardize because of ignorance of welding principles and procedures. Please approach welding with caution and take the time to learn as much as you possibly can.

[Aaron Novak]

Jim_P
I hate to admit this, but you are absolutely right. I have approached this subject from the wrong perspective. I failed to recognize that I have been dealing with individuals who are not fully cognizant of all the potential problems involved with welding processes, because they have no formal weld training. They don't know enough about welding, to realize they don't know enough and should not be welding critical aircraft structures. I forget that my original mechanic apprenticeship was four years long for a reason - there is just too much that can go wrong on an aircraft, if you are not fully aware all the things that can go wrong.

So I sincerely apologize to everyone for the way that I handled this subject. I hope that this entire conversation is not forgotten or discounted and that it does pass along the fact that welding is not easy. Welding critical aircraft structures should not be attempted by novice trainees unless they are under the direct supervision of a journeyman welder. Your life and the people you care about are much to precious to jeopardize because of ignorance of welding principles and procedures. Please approach welding with caution and take the time to learn as much as you possibly can.

Question: Why do you assume some of us are NOT professionally trained weldors or welding engineers with years of experience? Also, here in the USA there really is no generic journeyman welding card, they are specific for pipe welding, iron workers, etc. Here in the USA you typically attain a technical diploma, then do an apprenticeship in the specific field, or sometimes you can test out of the apprenticeship and go right to work. Aerospace is a little different with production workers usually being trained by the company while there are a couple very experienced people that work in the prototype shop. Canada might be a whole different thing and might be a little confusing for you then.

[nixrox]

Aaron:

Forgive if I am mistaken, but I don't remember seeing anyone on this particular blog (even you) stating they were journeyman welders. Yes, in Canada you cannot weld just about anything without being a journeyman certified by the Canadian Welding Bureau. on the aviation side you also have to pass the semi-annual welder performance testing to remain current and certified as an aircraft welder - and that is a difficult process to ensure only the best, most competent welders remain certified. So in that respect we are way ahead of you. However, I am not going to waste any more of my time arguing semantics with you.

I am going to include an article about purging the back side of shielded gas welding procedures, because it is pretty important. If after reading this article, you and everyone else trying to TIG weld 4130 tube - is not 100% positive their welds are defect free, then there is nothing more I am prepared to explore. This is just like the term we have all heard - 'IGNORANCE' of the law is no excuse. In this case, ignorance of the facts is no excuse.

In the military we introduced that process in 1976. I was working in an engine bay on large P&W turbines, when I noticed a significant crack on the titanium front frame. I took the engine over to the welding shop for repair and went back an hour later to get it. As I pulled it outside in the approx. 0C weather, there was a huge 'CRACK' sounded like a gun shot. Sure enough there was a larger crack in the exact same spot - back into the weld shop. This time they tried a more elaborate weld prep - with pre-heat and post-heat with slow cooling - same damn CRACK noise again. This time there was a 3 day consult involving a metallurgical engineer and a welding engineer. The end result, that no one had thought of before, was maybe contaminants were being introduced into the weld root from the un-shielded back side of the weld. So the welder came up with a way to plug the guide vane and attach a hose to allow Argon gas on the back side, at the same time as all the other things we tried before and it worked.

Purging Methods for Weld Purity

www.huntingdonfusion.com

By Dr Michael Fletcher of Delta Consultants


*Design, fabrication, and maintenance practices that can meet exacting
purity requirements of ASME 31.3 are crucial to the food,
pharmaceutical and semiconductor industries. *

Demands for improvements in piping fabrication quality have risen
exponentially in recent years.


Schematic section through tube joints illustrating gas seals on
each side of the weld. The identifiers show access routes for inert gas
supply/exhaust.The latest version of the ASME 31.3 Process Piping code Ref.
1) is a formal recognition of this emerging requirement that has been
stimulated mainly by the bioprocessing sector, but also by associated
industries such as pharmaceuticals, semiconductors, aviation and food production.

An essential element in pipework is production of welded joints. The
stringent inspection procedures imposed ASME 31.3 apply as much to
welded joints, as they do to all the other fabrication processes involved.

The article noted in Ref. 2 highlighted more general aspects of the
significance in the latest edition of the code, as it applies to the
manufacture of high-quality pipework.

Producers of welding accessories designed specifically to meet the
requirements have been quick to meet the new challenges ASME B31.3 impose.

*The Problem *

Pipe Stoppers Nylon Plugs

One of the fundamental requirements
imposed during the welding of pipes, is to prevent oxidation of the weld
during the first pass. The welding torch provides inert gas coverage of
the top of the fusion zone, but unless precautions are made there is no
coverage of the weld root. The problem has always been recognized and
over the years a variety of solutions have evolved, some eccentric,
others practical but largely ineffective.

While minimum standards are set for fusion welding, the application to
the pharmaceutical, semiconductor, and food production sectors demands
particularly high standards of cleanliness. Hygienic purity is the
driving force for joints destined for use in pharmaceutical and food
production. Elimination of particulate contamination is the crucial
requirement in semiconductor manufacture.

Inflatable Stoppers with some semiconductor manufacturers
producing chips with dimensions at the 32-nanometer (nm) level and
research going on at the 15-nm level, it is easy to see why the design,
fabrication, and maintenance practices required to ensure exacting
purity requirements of their process fluid distribution systems are of
paramount importance.

In the food processing industries, statutory legislation and a plethora
of litigation suits have forced plant manufacturers to introduce quality
control levels previously considered unnecessary. Contamination
introduced during fabrication is now unacceptable.

*The Solution *

Quick Purge Pipe Weld Purge System


Inserting low-quality paper or other barrier material on either side of
the joint and filling the space between them with inert gas may be good
enough for low-level requirements but is unsuitable to meet the
requirements ASME B31.3 imposes.

Significant progress was made in purging equipment in the 1980s when
welding accessory manufacturers developed expanding plugs and inflatable
stoppers (Figs. 1–3). These devices gave assurance of effective sealing
with the pipe wall and prevented leakage of inert gas from the weld
zone, thus precluding backflow of oxidizing gases from the atmosphere.

Hot Purge PreHeated Pipework Purge Systems

Generally effective,
these developments still allowed considerable scope for innovative
improvements. Devices such as shown in Fig. 4 integrate a pair of
inflatable bladders and provides pressure- controlled gas ports for both
inflating and inert gas supplies.

Other systems have been designed to satisfy the requirements of pre- and
postweld heating through the use of thermally resistant materials — Fig.
5. Some are produced with no metallic materials in the weld vicinity so
that postweld nondestructive examination can be undertaken with the
purge system still in place. There have been significant developments
recently in gas-monitoring instruments. These incude devices such as
monitors designed specifically for measurement of low oxygen
levels in purge gases during welding.

The challenges of the ASME Process Piping code have provided a stimulus
for further developments, and advanced versions of commercial purge
systems are becoming available. Some of these employ high-stability
engineering polymers to cover all exposed metal components so that the
risk of transfer of metallic materials onto pipe surfaces is minimized.
Many are able to provide fully automatic control over inert gas flow and
pressure. The welding supply industry is responding proactively to the
demands imposed by the latest edition of ASME 31.3.

/References/
1. ASME B31.3, Process Piping, Chapter X, High Purity Piping. 2010. New
York, N.Y.: American Society of Mechanical Engineers.
2. Huitt, W. M., Henon, B. K., and Molina III, V. B. 2011. New piping
code for high-purity processes. Chemical Engineering, July

[Aaron Novak]

Some of us do not feel the need to shove credentials around,and at least in my neck of the woods it is usually considered in poor taste and is seemingly reserved for academic types. Back purge is an interesting topic, and one that quite a lot of research has gone into. When we are dealing with 4130 in diameters typically used in GA there is no back purge as the limited oxygen supply is usually consumed quickly in the formation of an oxide scale. Critical weldments can use a backing flux for additional insurance. We can use the flux instead of a back purge as there is no concern for post weld cleanliness as there is in much of pipe welding. Pipe welding also having a much higher internal volume usually, would need more attention in that area. That being said, I am not aware of any 4130 piping. I know of no GA aircraft manufacturer that back purges any of their 4130 weldments, however I can check with my contacts to verify that. I would be curious if you have any failure reports on 4130 from oxide inclusion, Id love to see them. I have never found this failure mechanism in anything GA, instead finding a lot of HAZ issues and reinforcement (bead) geometry issues.

[nixrox]

Aaron:

In the real world outside of the USA, certification and licensing is not only required, but mandatory in just about every aviation, construction, petroleum and automotive profession I can think of. In fact, in the mechanical trades once you attain journeyman status, you can challenge any other related mechanical trade examination without having to undergo another apprenticeship. In addition, if you attain a score over 80% you automatically get 'RED Seal' approval and your certification is valid in every province and territory. You don't have to apply for provincial status examination every time you move. As for Non Destructive Testing our certification meets ISO 9000 certification and is valid in every country in the world that recognizes ISO. Why do I know this - it is because I have all those certificates.

Not like American Society of Non Destructive Testing which is not recognized outside of the company that issued it unless it is level 3 - but even that is being questioned because it is ASNT certifying their own ASNT members - not like ours, which is an separate government agency.

The first line in your statement above makes sense by the fact that you probably don't have any professional certification - you might have taken a materials science course in college - for all I know.
Yes, I am making that assumption based on the fact you have not mentioned anything about certification other than a vague reference to some welding, materials and NDT knowledge.
There is also your demonstrated lack of knowledge about basic welding process, procedures, codes and specification - you know - all those things journeymen have to know and demonstrate every day.
So for you - ignorance really is bliss.
Have another blissful day.

[Sam Buchanan]

In the real world outside of the USA, certification and licensing is not only required, but mandatory in just about every aviation, construction, petroleum and automotive profession I can think of.

Well...I think we have finally arrived at the crux of this discussion. It appears the USA is just plain inferior to the rest of the world, especially our good friends north of our borders. Perhaps someday we in the USA will be able to achieve the technological edge and skills that the rest of the world enjoys......and join the real world.

One more thought--I rarely attach much credibility to posts from individuals who don't sign their posts with their real name or have their name in their public profile.

[Frank Giger]

Let's take some of the heat out of the thread:

Nixrox, while I understand you're trying to promote best practices in welding, here in the USA that's all they are when it comes to Ultralights and Experimental Aircraft - recommended best practices.

No certification, rating, or anything else is required when constructing an Experimental aircraft, as they are by nature amateur built. Indeed, there isn't an Experimental aircraft flying in the USA with an airworthiness certificate. Not a single one. All of them are judged to be in a condition for flight, no more, no less....and that is made by the builder. The FAA simply acknowledges that they're airplanes with no judgement on their safety.

For ultralights, there isn't even that. The builder builds it and takes it into the air, no inspection or even a pilot's certificate required.

Now, then, we get to the line between allowed and prudent.

It is certainly allowed for the builder - regardless of prior experience or training - to weld up any portion of their aircraft as they desire.
It is also certainly prudent for the builder to either accept help and supervision when it comes to welding or even pass that task on to someone else if they are inexperienced.

Fortunately, there is this big ol' organization full of people who build airplanes (or have a keen interest in it) where one can go for help, find a mentor, and ensure they're on the right track and staying safe. ;)

[nixrox]

Aircraft Welding


I have been an Aircraft Mechanic and then a Non Destructive Inspector for more than 50 years. My guiding objective has been and always will be – SAVING LIVES.





So keeping this goal in mind, my career has been focussed on the detection of defects and the removal of those defects, before they become failures. Failures in aircraft usually means dead pilots, passengers, people on the ground and the destruction of aircraft.


Imagine my surprise, when reading a blog in the USA, Experimental Aircraft Association forum, were amateur aircraft builders are discussing different techniques of Tungsten Inert Gas (TIG) welding of 4130 steel tubes – and there is not one word about welder training, certification, weld procedures or quality assurance inspection of their completed welds.


Then I find out that 3 pilots were killed and 18 aircraft crashes have occured since 1996 with FAULTY WELDS being listed as the main probable cause of the crash.


HOW and better yet WHY has this folly been allowed to continue?


It has always been my experience in the aircraft industry, if we find a defect that was the root cause of an aircraft crash, we do everything in our power to remove that defect from every other similar registered aircraft, before there is another person killed, or aircraft destroyed.


In this case, I believe the FAA and the EAA (as well as my own Canadian - RAA), have dropped the ball and allowed 17 more aircraft crashes with 3 deaths and neither organization has done anything to mitigate the totally PREVENTABLE root cause – weld defects.


I firmly believe that WELDING is one of the most difficult to master of all the skilled trades.


With proper welder training, welder supervision, weld procedures and design engineering, pre-weld testing and quality assurance inspection after completion - these deaths and crashes might not have happened.


It has always been impossible to guarantee 100% defect free products – we are human we are not infallible – but we do have the ability to reduce the potential death and destruction to a small fraction of what has occured.


On a scale of the most difficult and restrictive welding processes:
1. Nuclear powered submarines
2. Nuclear powered electricity generation
3. Aircraft
4. Everything else


It is somewhat different for Non Destructive Testing inspectors in that absolutely NO DEFECTS are allowed in the first three catagories and the fourth is goverened by ASME and other welding codes for allowable defect sizes and locations.


In my experience – the perfect weld is one I can’t even see on the x-ray film. It is exactly the same thickness and density as the parent material on either side and there are no defect indications.


However no inspection method is 100% perfect - for example X-RAY.


If I do not place the focal spot of my x-ray tube at exactly 90 degrees to a small tight crack – if I am off by as little as 10 degrees, I will not be able to detect that crack. So we try shooting x-rays at several angles and followup with a surface detection method like ultrasonics, or liquid dye penetrant, or magnetictic particle, or eddycurrent.


My point is – we can and should be doing more to reduce the number of preventable defects in ALL aircraft welds – anything less is totally unacceptable.


So I am going to do my best to raise awareness of this issue - first with the FAA and EAA , as well as Transport Canada Airworthiness safety and RAA.


At the same time, I am going to include aircraft insurance underwriters, financial institutions and finally last but not least the news media.


If I am able to prevent one human death - it will have been worth my effort.

[nixrox]

Sam Buchanan - if the shoe fits - it is about time you recognized the problem.

I'll will give you just one aircraft related example out of thousands that I have seen over the years. Back about 25 years ago an Hawiian Airlines Boeing 737 became a convertible at 10,000 feet when 20 feet of the upper fuselage ripped off. Several people died, but the pilots managed to land the aircraft without further losses. The root cause - undetected fuselage cracks in one of the lap seams. Boeing had issued a mandatory eddy current inspection and the airline did comply. BUT the way they were allowed to comply was unbelievable. They bought an eddy current machine and the manufacturer provided two hours of training to one of their inspectors. The inspector really had no idea what he was doing and should never have been allowed to conduct that inspection.

In Canada - that never would have happened. An eddy current inspector must successfully complete a one week course, 3 months of practical field experience under the direct supervision of a level 2 supervisor and then a set of government exams to gain a level one certificate. Then the inspector must complete another set of 3 week training programs, plus 9 more months of practical experience under the direct supervision of a level 2 inspector and then two more written government exams as well as two days of practical tests were they demonstrate their ability to detect defects before they would be considered qualified to inspect those fuselage lap seams.

Aircraft x-ray certification is ten times more difficult and very expensive - up to more than $2000.00 just for examination and course fees.

I rest my case.

[Bill Berson]

There is 11 or more Non-destructive Testing methods. The most common method (80%) is visual.
The manufacturer selects the appropriate NDT method. (AC 43.13-1B)

[Sam Buchanan]

In Canada - that never would have happened.

Mr. nixrox (for some reason I doubt that is your actual name....) you are correct. Canada definitely has the superior system of inspection. I just don't know how to explain the thousands of experimental aircraft that fly safely every year in the unregulated, anarchic USA. I still haven't figured out how the multitudes of USA-made experimental components, kits and finished aircraft that are imported into Canada are allowed to populate your airspace. Somebody needs to do sumthin'..... ;)


I rest my case.

Ok. :)

[Aaron Novak]

In the experimental world, I worry more about guys using car engines, but that is the spirit of the category right?

[martymayes]

"3 pilots were killed and 18 aircraft crashes have occured since 1996"

Three fatalities in 22 yrs? There outta be a law!

[nixrox]

If you all are so proud of your welding - where is the x-ray proof?

At the very least, you should be required to complete a set of similar type weld tests in front of a certified independent QA specialist. The test samples would be inspected visually first and if that is successful, then they get radiographed. With the criteria established that NO DEFECTS are allowed, the x-ray evidence will certainly weed out the poor and mediocre welders. The home builder should not be allowed to weld anything on an aircraft until he successfully completes the practical demonstration of his skills. When the successful candidate completes his aircraft welding, a certified weld inspector has to inspect and sign off on the air frame - before the home builder encloses it.

The above outlined solution, when compared to what is being done now - I believe aircraft crashes due to faulty welding should be an extremely rare occurrence.

[Sam Buchanan]

If you all are so proud of your welding - where is the x-ray proof?

At the very least, you should be required to complete a set of similar type weld tests in front of a certified independent QA specialist. The test samples would be inspected visually first and if that is successful, then they get radiographed. With the criteria established that NO DEFECTS are allowed, the x-ray evidence will certainly weed out the poor and mediocre welders. The home builder should not be allowed to weld anything on an aircraft until he successfully completes the practical demonstration of his skills. When the successful candidate completes his aircraft welding, a certified weld inspector has to inspect and sign off on the air frame - before the home builder encloses it.

Mr. nixrox, (stilll wondering why you are hiding behind a screen name since you intend to carry your demands to the EAA, FAA, Canada, insurance companies and the news media) you keep forgetting this is an experimental aircraft community. You advocate imposing NASA-level inspections on experimental aircraft construction. Do you have any real experience in the experimental aircraft universe?


The above outlined solution, when compared to what is being done now - I believe aircraft crashes due to faulty welding should be an extremely rare occurrence.


They are already extremely rare......

Your arguments are getting more and more bizarre the longer you push your opinions. They are, however, pretty entertaining to read. :)

But I think I'm ready to sign off.

[rwanttaja]

The above outlined solution, when compared to what is being done now - I believe aircraft crashes due to faulty welding should be an extremely rare occurrence.
But they are now. Roughly one accident among the homebuilt fleet occurs each year. Out of 28,000 homebuilt aircraft in the US, that's an accident rate of about 0.01%. Go by the fatal accidents only, it's even less.

In contrast, about 18 homebuilt accidents per year have occurred because the pilot stalled a perfectly good airplane....about half of them fatal. This doesn't even include the stalls that occur when a pilot is trying to force-land a plane with a dud engine. Seems that a cheap, retrofitable stall-warning device would save more lives.

Ron Wanttaja

[nixrox]

Dear Sam Buchanan and everyone else on this web site:

You need to consider every word you type on the internet for one simple reason - Everything you type on the net stays on the net forever.

When an employer or a company doing business with your company types your name for a bit of background information about you - all of this information is clearly available to anyone.

Take Sam for example:
If he were to submit an application for employment with any aviation or related company - the potential employer would have written evidence that he might not be a good candidate given his responses on this blog.
If he owns a company or is in a management position - a purchasing customer might not wish to do business with his company based solely on his responses in this blog.

So please take care with your written opinions on these types of blogs.
Regards
NixRox

[jim_p]

Curiouser and curiouser...

[cwilliamrose]

Scare tactics? That's what you have resorted to in order to silence your critics? Pathetic. You better hope no one important reads what you have written.

[Aaron Novak]

One thing I don't understand about your position Mr. NixRox, is why you are seemingly so anti-experimental, when your dad flies (or flew) an experimental C172 with a supercharged ( to 430 HP) GM LS engine on it? I'm not being critical, it just appears very contradicting.

[rwanttaja]

Dear Sam Buchanan and everyone else on this web site:

You need to consider every word you type on the internet for one simple reason - Everything you type on the net stays on the net forever.

When an employer or a company doing business with your company types your name for a bit of background information about you - all of this information is clearly available to anyone.

Take Sam for example:
If he were to submit an application for employment with any aviation or related company - the potential employer would have written evidence that he might not be a good candidate given his responses on this blog.
If he owns a company or is in a management position - a purchasing customer might not wish to do business with his company based solely on his responses in this blog.

So please take care with your written opinions on these types of blogs.
Regards
NixRox
Gracious....

We have to assume Nixer is either,

1. Solicitous of the Sam's welfare to the point that he offers a heart-felt concern for his well-being, or
2. Attempting to intimidate Sam into staying silent.

We'd better assume #1, since #2 might be considered contrary to the Forum's rules about abusive behavior.

Oh, and Nixer: This is a *forum* not a blog.

I've been online for about 35 years. I've been P.O'd, and I've P.O'd other people. I've told the truth as best I could, and have tried to be as correct as posible (with less success, sadly). What I've posted has gotten me sued once, and what other folks have said about me on the Internet has started security investigations on me.

I have been wide open, in public view on the Internet since 1984. It made zip difference in my career. I retired last year with all the fun tickets still intact.

Sure, there have been cases where what people have said/done on the Internet has affected their working lives. But you probably can't point to *one* that was triggered by a difference in technical opinion. It has happened when people have revealed drinking issues, or racism, or bad-mouthed their bosses.

I've never heard of ONE where a person got fired...or missed out on a job...because they had a strong-held technical opinion, especially when they could explain their reasoning as succinctly as Sam. I think most employers would LOVE to have an articulate and knowledgeable person like Sam on their staffs, even if they don't see eye-to-eye on some technical subjects.

I don't argue with people staying anonymous on the Internet. I never have, but have known folks who have had "other lives" to protect. One man is the son of a legendary TV star. Another is a fairly prominent FAA official. Others have been prominent writers.

They do have a trait that sets them aside from Tricky Nixer: They don't wrap themselves in a pseudonym gillie to snipe at other people from anonymity. They make passionate technical arguments, but leave personalities out of it. They don't claim massive technical expertise, because their anonymous status means thay can't prove it. They make it clear from the quality of their arguments, not from attempts to shout down others with claimed experience.

There's an age-old online axiom: "On the Internet, nobody knows you're a dog."

Ron "Bad Dog. No biscuit." Wanttaja

[Bill Berson]

I may be a certified weld inspector and licensed NDT Inspector but my welding sucks.
I complete all the mechanical work and farm out the welding and upholstery to the experts.
have a nice day.

Who would hire a weld inspector that can't weld?
That's like hiring a check ride examiner that can't land a taildragger.

[Sam Buchanan]

Dear Sam Buchanan and everyone else on this web site:

You need to consider every word you type on the internet for one simple reason - Everything you type on the net stays on the net forever.

When an employer or a company doing business with your company types your name for a bit of background information about you - all of this information is clearly available to anyone.

Take Sam for example:
If he were to submit an application for employment with any aviation or related company - the potential employer would have written evidence that he might not be a good candidate given his responses on this blog.
If he owns a company or is in a management position - a purchasing customer might not wish to do business with his company based solely on his responses in this blog.

So please take care with your written opinions on these types of blogs.
Regards
NixRox

Just when we thought it couldn't get any more bizarre.... :rollseyes:

Happily retired in my seventh decade (including three decades of internet and publishing history)!! :)

[martymayes]

The above outlined solution, when compared to what is being done now - I believe aircraft crashes due to faulty welding should be an extremely rare occurrence.


3 fatalities in 22 yrs!!?? It's already an extremely rare occurrence!!!

The above outlined is a solution looking for a problem!

[Frank Giger]

If you all are so proud of your welding - where is the x-ray proof?

At the very least, you should be required to complete a set of similar type weld tests in front of a certified independent QA specialist. The test samples would be inspected visually first and if that is successful, then they get radiographed. With the criteria established that NO DEFECTS are allowed, the x-ray evidence will certainly weed out the poor and mediocre welders. The home builder should not be allowed to weld anything on an aircraft until he successfully completes the practical demonstration of his skills. When the successful candidate completes his aircraft welding, a certified weld inspector has to inspect and sign off on the air frame - before the home builder encloses it.

The above outlined solution, when compared to what is being done now - I believe aircraft crashes due to faulty welding should be an extremely rare occurrence.


Wait, are you sure you're on the right set of forums?

What you're suggesting is only certified welders be allowed to work on homebuilts, and that their work to be x-rayed and then signed off by an FAA inspector at every step.

At that point where is the amateur in amateur builder? One of the twin pillars of why Experimental Aircraft are encouraged by the government in the first place is Education. The second is recreation.

You're advocating something other than that, where only experts should be allowed to build and pilot their own aircraft, something that will not be looked on favorably by the EAA.

[nixrox]

Frank Giger

NO I am not suggesting ONLY certified welders be allowed to weld on homebuilt aircraft.
I am suggesting that anyone who wants to weld parts together on a homebuilt aircraft should be required to demonstrate their skill in front of any journeyman welder in the USA, by welding three sample welds similar to what is required for their aircraft.
Then the weld sample should be inspected visually by any journeyman welder and x-rayed at your nearest NDT shop. If there are no defects then the homebuilder is approved by the EAA to start welding his aircraft.

This simple demonstration would probably weed out most of the trainee welders in a hurry. It would reduce failures due to faulty welding and save pilot lives.
I also believe that if a homebuilder does not choose to provide samples of his welds, then this hombuilder should be restricted from flying anywhere near a populated area and never be allowed to take up passengers.
This way he will only hurt himself, if his welds fail.
Otherwise the carnage and loss of pilot lives will continue unabated.

Here is a quote I saw recently and it certainly applies to this forum:

THE MORE YOU KNOW
THE BETTER YOU KNOW
HOW LITTLE YOU KNOW

This little discussion has certainly changed my mind about purchasing any aircraft built or maintained in the USA by FAA certified mechanics.
I always thought your aircraft mechanic certification was closer to ours - apparently I was misinformed.
ISO9000 certification will be my acceptance guide, plus an in depth analysis of the log books.
Have a happy day.

[Aaron Novak]

The EAA is not a regulatory body. There is no such thing as a journeyman aircraft welder in the USA, that title does not exist. When I was looking up the requirements to me an Aircraft Maintenance Engineer in Canada I saw no mention of them being required to hold a journeyman card in welding. Is that not the case?