ER70S6 vs RG45

[Mike Switzer]

I was getting a couple other things from tinmantech.com & I noticed they sell ER70S6 for welding 4130 instead of the RG45 that I have seen recommended elsewhere.

Since I was getting other stuff anyway I bought a pound to play with, this is what they say on the website:

"Our filler rod for 4130 Chrome Moly is NOT 4130 alloy. Rather, we offer what engineers, welders, and experience shows to be the best choice for welding structures of tubing and sheet: ER70S6. I know we recommend something a little different on the 4130 Airframe Video, but I can't help making little improvements as I discover them, or as they become available. So it is in this case. This filler has great penetration and little spatter, flows evenly, and is reasonably priced."

Anyone have any opinions on the difference between the 2?

[Sam Buchanan]

I was getting a couple other things from tinmantech.com & I noticed they sell ER70S6 for welding 4130 instead of the RG45 that I have seen recommended elsewhere.

Since I was getting other stuff anyway I bought a pound to play with, this is what they say on the website:

"Our filler rod for 4130 Chrome Moly is NOT 4130 alloy. Rather, we offer what engineers, welders, and experience shows to be the best choice for welding structures of tubing and sheet: ER70S6. I know we recommend something a little different on the 4130 Airframe Video, but I can't help making little improvements as I discover them, or as they become available. So it is in this case. This filler has great penetration and little spatter, flows evenly, and is reasonably priced."

Anyone have any opinions on the difference between the 2?

I can't compare the two fillers but I did purchase ER70S6 based on the Tinman recommendation and used it to oxy weld my Legal Eagle fuse. I was very pleased with the results.

[Mike Switzer]

That is good to know. I will play with it some & see what happens.

First I have to try to fix a cast iron bearing housing (that was what I was originally getting was some flux & cast iron rod)

[Aaron Novak]

That is good to know. I will play with it some & see what happens.

First I have to try to fix a cast iron bearing housing (that was what I was originally getting was some flux & cast iron rod)


This is one of only a couple situations where Kent and I differ. I personally do not like using electric fillers for gas welding, mainly due to the electric fillers having alloying elements not needed in the OA process. I believe you will find MORE sparking and such with the electic fillers, at least I have. RG45 is a good basic use material, RG60 makes some beautiful sound welds that loot almost "buttery". From a strength or fatigue standpoint there should not be an issue either way, the ER70 series lines up pretty well with the RG60 in the performance of the finished weldment.

[Max Torque]

Best thing to do is to check with the American Welding Society and/or tech support at Lincoln and/or Miller. I did with Lincoln & Miller - being sure they clearly understood I wanted information for oxy/acetylene welding - and, after they checked on it, was steered in the ER70S-6 direction, but they said RG45 works fine too albeit with a bit lower tensile strength. RG45 is a bit easier to weld with. I've used, and still use, both, but RG45 mainly for gas. (I weld MIG, TIG, & oxy/ace.)
EAA video addressing gas welding filler rod:
http://www.eaavideo.org/video.aspx?v=1553988082001
Looks like R-65 is the filler rod of choice.
Tom

[Mike Switzer]

RG45 is a good basic use material, RG60 makes some beautiful sound welds that loot almost "buttery".

Would that be the silver colored rod that we used in the Sportair workshop I took a few years back? I know we started with RG45 then switched to something else, there was quite a bit left over & they didn't want to haul it back so most of us took some home to play with. I still have some of the coupons & short pieces of tube left over, I think when my new torch gets here I will try using both side by side & see what they look like.

[Neil]

RG(think Rod-Gas) 45 and 60 are usually considered O/A wire and ER(think Electric Rod) 70 and 80 Tig wire. This is at least how I view the difference.

While the RG45 shows to have the lower overall strength of these wires, if proper technique is used the tubing will still fail before the weld.

As I've grown older and less steady I find O/A more forgiving of my shakiness than TIG. Unless I can get braced up really well on a TIG project I seem to be forever sticking the tungsten.

[Max Torque]

Neil, good way to view and remember the differences. What you said about overall strength is right on the money - the tube will fail before the weld.

Since there are no FAA certified welders, let's go to the place that actually does certify welders for input on filler rod - The American Welding Society(AWS) - and see what they have to say...
AWS sums it up nicely in their handbook and AWS specifications (AWS5)
From AWS’ Welding Inspection Technology book (Chapt. 3)
" ’ER’ designates the wire as being both an electrode and a rod, meaning that it may conduct electricity (electrode), or simply be applied as a filler metal (rod) when used with other welding processes."
and
“The ‘R’ designates it as a rod,‘G’ stands for gas”
However, when we go to pertinent parts of AWS5 (AW5.2 and5.18) we see the following tidbits:
“The welding electrodes and rods classified under this specification are intended for gas shielding arc welding, but that is not to prohibit their use for any other process for which they are found suitable.”
and
“The welding electrodes and rods classified under this specification are intended for oxyfuel gas welding, but that is not to prohibit their use for any other process for which they are found suitable.”
ER70S -2 and -6 are suitable for OFW welding 4130 tube. Are they the best for the application? Perhaps not, but they are suitable. However, RG45 or RG60 or RG65 are more suitable.

Cheers and Happy New Year!
Tom

[Aaron Novak]

Neil, good way to view and remember the differences. What you said about overall strength is right on the money - the tube will fail before the weld.

Since there are no FAA certified welders, let's go to the place that actually does certify welders for input on filler rod - The American Welding Society(AWS) - and see what they have to say...
AWS sums it up nicely in their handbook and AWS specifications (AWS5)
From AWS’ Welding Inspection Technology book (Chapt. 3)
" ’ER’ designates the wire as being both an electrode and a rod, meaning that it may conduct electricity (electrode), or simply be applied as a filler metal (rod) when used with other welding processes."
and
“The ‘R’ designates it as a rod,‘G’ stands for gas”
However, when we go to pertinent parts of AWS5 (AW5.2 and5.18) we see the following tidbits:
“The welding electrodes and rods classified under this specification are intended for gas shielding arc welding, but that is not to prohibit their use for any other process for which they are found suitable.”
and
“The welding electrodes and rods classified under this specification are intended for oxyfuel gas welding, but that is not to prohibit their use for any other process for which they are found suitable.”
ER70S -2 and -6 are suitable for OFW welding 4130 tube. Are they the best for the application? Perhaps not, but they are suitable. However, RG45 or RG60 or RG65 are more suitable.

Cheers and Happy New Year!
Tom

One bit to keep in mind when looking at electric vs. OA fillers, is that the strength classifications are not directly comparable. They are rated differently under different situations and the actual number should be taken with a grain of salt. When you interalloy the fillers with the base metal durring the welding process, the resultant strength of the weld deposits are not that different, and in the case of gas welding are much higher than the fillers rating. You are not going to have a strength concern in a typical homebuilt with any of the mentioned fillers provided everything else about the joint is correct. However.....there are times when in the design of a specific part, a filler of a specific class is needed, and this is usally called out on the drawings.


The sport air shops use both 45 and 60. 60 is the bare filler previously sold under the name Linde #1 HT ( High Test ), and Linde Planeweld (which in later years became one of the first Tig fillers to be used in the aviation industry).....pretty cool eh?

[Mike Switzer]

However.....there are times when in the design of a specific part, a filler of a specific class is needed, and this is usally called out on the drawings.

Many years ago I worked for a company that designed air & hydraulic lifts, tilt tables, etc. for automotive assembly lines. They made me the structural / welding engineer & I had to do that on occasion. I had an old copy of the Lincoln Electric Weld Engineering manual that made things a bit easier, and some dirty rat stole it from me when I was at a later job.


The sport air shops use both 45 and 60. 60 is the bare filler previously sold under the name Linde #1 HT ( High Test ), and Linde Planeweld (which in later years became one of the first Tig fillers to be used in the aviation industry).....pretty cool eh?

Cool

[Aaron Novak]

Many years ago I worked for a company that designed air & hydraulic lifts, tilt tables, etc. for automotive assembly lines. They made me the structural / welding engineer & I had to do that on occasion. I had an old copy of the Lincoln Electric Weld Engineering manual that made things a bit easier, and some dirty rat stole it from me when I was at a later job.



Cool

Ive got a couple versions of the lincoln book, and like any engineering book written by a company that makes products related to the subject, is biased. The information is good, but heavily leaning towards electric welding ( for obvious reasons ). The Linde books leaned towards OA welding, again for obvious reasons. Somewhere in between lies a happy truth. The AWS I have found to be biased as well many times, as the people sitting on the councils are usually equipment industry people. The ASM seems to be the best independent source. The further you dig into this subject, the more confusing things seem, until you hit the point where you start questioning the motives of textbook writers, then it all becomes pretty simple.

[Max Torque]

Aaron, I totally agree!
Tom

[Bugs66]

Go with RG45. Been there done that. When you run out of electric rod, now you have to order more from Tinman vs RG45 found everywhere locally. The RG just welds a lot better for O/A. Like others said, the ER splatters a lot and not as forgiving.

[Mike Switzer]

When you run out of electric rod, now you have to order more from Tinman vs RG45 found everywhere locally.

Around here finding anything but arc welding rod (even at the welding shops) is a challenge. One of the farm stores carries RG45 but the smallest they have is 3/32" & they are always out of stock. If I want to use RG60 I will have to order it anyway, either online or from my local welding shop.

[Sam Buchanan]

Go with RG45. Been there done that. When you run out of electric rod, now you have to order more from Tinman vs RG45 found everywhere locally. The RG just welds a lot better for O/A. Like others said, the ER splatters a lot and not as forgiving.

Maybe my situation is different than most. ER is more readily available locally in small diameters than RG, matter of fact RG is sorta scarce. And in the course of welding my Legal Eagle fuse I didn't have any issues with ER70S6 spattering (1/16" diameter, Meco Midget torch). I found it easy for this low-time oxy-gas welder to use. I'm not trying to sway anyone's choice, just stating my experience.

By the way, my Eagle XL is featured in the January 2013 issue of KitPlanes magazine in case someone wishes to see the finished plane.

[Aaron Novak]

Sam,
Have you used any of the RG's as well to any extent, or is your experience strictly with ER fillers?

[Sam Buchanan]

Sam,
Have you used any of the RG's as well to any extent, or is your experience strictly with ER fillers?

My intention was to use RG45 per the recommendation in the Tinman videos. But the only RG45 I could find locally was 1/8" diameter...I tried it and wasn't happy with it while welding 0.035" tubing. So I ordered some 1/16" ER70S6 (later found it locally as well), was pleased with how it welded, and finished the project with it.

The Eagle was my first welded steel aircraft project, previous planes have been wood or aluminum.

[Aaron Novak]

Sam,
I think if you put some hours in with other fillers, you will find that some are a little nicer to use. In reguards to the size of the 1/8 filler with your .035 tubing, believe it or not that was standard practice in the 1940's in a production shop. Big tip, big filler, and clusters that get welded up in seconds.

[Mike Switzer]

In reguards to the size of the 1/8 filler with your .035 tubing, believe it or not that was standard practice in the 1940's in a production shop. Big tip, big filler, and clusters that get welded up in seconds.

I would think they would have had problems burning holes thru the tube.

[Sam Buchanan]

Sam,
I think if you put some hours in with other fillers, you will find that some are a little nicer to use. In reguards to the size of the 1/8 filler with your .035 tubing, believe it or not that was standard practice in the 1940's in a production shop. Big tip, big filler, and clusters that get welded up in seconds.

Moot point now, my plane is built and I enjoyed the welding process. If I weld another one, I see no reason to make any changes.

Don't really care what they did in the 1940's on production lines...........

Hey....I'm not trying to convince anyone to weld a particular way, just answered the original poster's questions for feedback. If someone wants to use a different method than what I used......go for it. :)

[Aaron Novak]

I would think they would have had problems burning holes thru the tube.

Not once you get the hang of it. Actually the larger filler is easier when welding hot and fast as it acts as a heat sink.

Sam,
Not picking at what you chose to do, just adding a historical perspective. My guess is that your preference came from being unexperienced and trying to learn using too large of a filler with the RG, and that the difference you saw was due more to wire size than alloy ( and there is nothing wrong with that ). Im sorry if you were offended by the suggestion of trying something else, but I do still stand by it. If you want to try some RG-60 and RG-45 in 1/16 let me know and I will send a few pieces your way.

[Mike Switzer]

Not once you get the hang of it. Actually the larger filler is easier when welding hot and fast as it acts as a heat sink.

What size tip would you use welding thin tube with 1/8" rod? (For Smith AW1A if you know it, otherwise I can look at the cross reference chart)

[Sam Buchanan]

Sam,
Not picking at what you chose to do, just adding a historical perspective. My guess is that your preference came from being unexperienced and trying to learn using too large of a filler with the RG, and that the difference you saw was due more to wire size than alloy ( and there is nothing wrong with that ). Im sorry if you were offended by the suggestion of trying something else, but I do still stand by it. If you want to try some RG-60 and RG-45 in 1/16 let me know and I will send a few pieces your way.

No offense taken, it's just that I'm happy with the results I got with ER70S6. And if you prefer to use RG....I'm fine with that.

I did a lot of reading in the course of getting ready to weld the Eagle fuse, and it seems the ER fillers are rapidly gaining acceptance in oxy-gas welding. No doubt this is reflected in the move to ER filler by the highly regarded Tinman guys. RG has a lot of field history and is still the go-to filler for a lot of welders, but it is no longer the only option.
Of course, nearly everyone will be using TIG in years to come so this will all be moot. :)

[Mike Switzer]

Of course, nearly everyone will be using TIG in years to come so this will all be moot. :)

Yea, right... I can't afford that. Well, I probably could, but I can't justify it when a torch does the job for a lot less. Especially when my buddy has a tig if I really really want it welded that way.

[Aaron Novak]

No offense taken, it's just that I'm happy with the results I got with ER70S6. And if you prefer to use RG....I'm fine with that.

I did a lot of reading in the course of getting ready to weld the Eagle fuse, and it seems the ER fillers are rapidly gaining acceptance in oxy-gas welding. No doubt this is reflected in the move to ER filler by the highly regarded Tinman guys. RG has a lot of field history and is still the go-to filler for a lot of welders, but it is no longer the only option.
Of course, nearly everyone will be using TIG in years to come so this will all be moot. :)

Still going to want a torch if youre using 4130....... :) Besides I dont feel like getting skin cancer if I can avoid it.........

[Sam Buchanan]

Still going to want a torch if youre using 4130....... :) Besides I dont feel like getting skin cancer if I can avoid it.........

I like using a torch, sorta old-school.

But a torch is scarcely seen these days in aircraft production or race car shops that fabricate with 4130.

And I'm dealing with skin cancer already, not from TIG but from living on a planet illuminated by a huge UV generator...........life is risky.......

[Aaron Novak]

Yep rarely seen, mostly due to economic and marketing reasons, I mean hey, who doesnt love some shiny machine with all sorts of knobs and displays on it in their shop, makes it look like you know what you are doing to the uneducated.........:)

BTW I own and use 2 very nice inverter Tigs in my own shop......so my choice of technology for a given application is driven by engineering reasons, not personal capability.

[eiclan]

Gday chaps,A most interesting discussion,Here in Aussie the mig wire I use is the er70s6, it would seem then that I can tack weld my fuse frame with the mig and then either tig weld or oxy weld the frame with the same er70s6 filler rod,how convenient.I just wonder at whether there is a different melt point between the 70 series fill rod and the rg 45 and 60.Any thoughts? Ross

[Aaron Novak]

Gday chaps,A most interesting discussion,Here in Aussie the mig wire I use is the er70s6, it would seem then that I can tack weld my fuse frame with the mig and then either tig weld or oxy weld the frame with the same er70s6 filler rod,how convenient.I just wonder at whether there is a different melt point between the 70 series fill rod and the rg 45 and 60.Any thoughts? Ross

Ross,
Only a few degrees difference between the fillers. Provided the tacks are small, I dont really see an issue tacking with a Mig, however I guess I dont see an advantage either. You would have to be sure that the weld would completely re-melt the tack( including the parent metal under it ) forming a wider fillet than the tack itself in the end. Tacking with an O/A torch takes a couple seconds, same for tig, and the tacks are very controlled. I would think tacking with a mig would be cumbersome, producing large, "cold" tacks, and thus would be my personal last choice.

[eiclan]

Gday Aaron,You are right in respect to "cold tacks" produced by the mig welder but as someone who has built many experimental agricultural machine and have tacked them all together and built them and then dismantled them and fully welded,the production of a good tack weld is very important for not only the structural integrity but also the squareness of the finished product. The trick to getting the mig to produce a good small and strong tack weld is to ensure as higher amperage as is possible,commensurate with the thickness of the material,with the least amount of wire feed.Wire feed controls the size of the pool,amps the heat of the pool.the more wire the larger the tack.Because the tack weld is of short duration the amps need to be high to get full penetration while less wire ensures a flat tack weld. Cheers Ross

[Aaron Novak]

Gday Aaron,You are right in respect to "cold tacks" produced by the mig welder but as someone who has built many experimental agricultural machine and have tacked them all together and built them and then dismantled them and fully welded,the production of a good tack weld is very important for not only the structural integrity but also the squareness of the finished product. The trick to getting the mig to produce a good small and strong tack weld is to ensure as higher amperage as is possible,commensurate with the thickness of the material,with the least amount of wire feed.Wire feed controls the size of the pool,amps the heat of the pool.the more wire the larger the tack.Because the tack weld is of short duration the amps need to be high to get full penetration while less wire ensures a flat tack weld. Cheers Ross

Ross,
I should have noted before that I have used the Mig process for tacking, however have found that on material in the thickness that we use in aviation, that there is almost no time saved, and the cumbersome nature of the Mig torch seemed to counteract any potential time savings. On heavy material like the Ag world, a different story is presented as you have described.