TIG Welding Machines (what am I looking for?)
So, I'm thinking of building a Milholland Double Eagle for my first plane. The fuselage is 4130 steel tubing and the original was made using a gas welder. I want to go TIG because it seems to be better in many respects, just harder to do.
Now comes the question; what machine would work best for me and grow with me as I move up to more complicated aircraft like Sonerai or the like?
I saw where Aircraft Spruce has one (the Invertec V155-S) that is small and affordable but I'm worried that it won't grow with me. I surely can't afford to spend $3k on this but I also down want to throw away $1.5k either!
Has anyone used this machine or simular power machines and how does this scale when I start building the more complex and larger aircraft?
Thanks for your time,
Sub, check out the Miller Diversion 165/180 machines. They use pulse technology, make quality welds and are very easy to use. I rented one this past summer for a couple jobs and I liked it better than my old Syncrowave machine I had years ago. I plan on buying one if enough work piles up.
Street price for a 165 is ~$1400 and if you decide you don't need it you can sell it and get your money back because being a name brand it holds it's value very well. Don't waste your money on off-name brands, cause you will be disappointed and you can't get rid of it without taking a beating on price.
Buy Miller, Lincoln, or Hobart. You can get parts & service in most decent sized towns, they all make good products & the companies will be around for along time. Millwright & pipefitting firms are always watching for used models of those 3 brands so you can get a decent price if you want to sell it. The off name brands may work OK, but like Marty says, you cant sell them easily because people assume you are getting rid of it because you didn't like it.
Originally Posted by martymayes
I totally agree with Martymayes - the little Miller machines will handle anything you need to do with Chromemoly and they are a very good value and hold their resale. You do not need anything more for aircraft materials. The bigger and more expensive machines can handle thicker plate, but you will never need to weld something better than 3/8 inch thick.
When you look at the Miller Diversion models, you can weld aluminum with the more expensive one, for like another $200 give or take. This is a nice feature to have. And...the Diversion models run on either 110 or 220 so if you don't have 220 installed, you don't need to go through the expense of that. The only thing is when you run it on 110 if you are welding something really thick and welding continuously, it will blow a 20 amp breaker consistently. But for aircraft thickness materials, you will be fine. More complex aircraft doesn't necessarily mean much more heavier tubing and plate and you will be fine with the little Miller machines. I have used them and their big brother counterparts in many welding classes under the supervision of an instructor who was a welder in the Air Force for a career, and now welds aircraft parts as his second career and he owns nothing but Miller and in many sizes including the Diversion series.
And another thing, if you can gas weld, you can most certainly TIG weld. You have more control with TIG. When you are welding up clusters, it can be tough to have the space to get in there with the torch, where-as it would be easier with gas. But there are pencil thin torches that you can use for when space is limited.
i have one of these:
It does every thing I need, stick, tig alu/steel.
try to find one used for around $500.00
Dumb question, why do you feel that Tig is "better" for you? I assume you already have a torch setup? If not I would invest in one along with the Tig machine as you will likely want one for tempering critical weldments and the like.
Originally Posted by subnoize
Errr, I own nothing right now or I wouldn't be asking questions. What I had read is gas heat the surrounding material which is bad in things like aircraft and race cars. For bending tube I was going to get a set of small brazers but was going to skip gas otherwise. This is really a money issue, otherwise I wouldn't be building a Double Eagle but I still want to get what technological advances I can for the money. After all, I wnt to fly my kids around in this thing safely, right?
Originally Posted by Aaron Novak
I own a nice little Lincoln mig & I can borrow a Lincoln Pipeliner whenever I need it, I do 90% of my welding with a torch. The only time recently that I felt something would be better being tig welded was when I needed a fairly heavy pipe fitting welded to the bottom of a fairly thin walled fuel tank.
Ok it sounds like you might not have too much information on this subject so let me help you out a bit. The material you are working on was developed in the mid 1920's and fabricated using both arc (stick) and o/f (gas) welding in aircraft structures until about 1960 when Tig slowly started to take their place due to better economy for production ( no post weld cleaning operations needed etc. ). 4130 is what is called a low-alloy steel, and due to the levels of chromium and other elements, it is heat treatable and can attain very high hardness ( with low ductility ) even though it has a lower carbon content. This comes from the fact that the material uses a martensitic base structure vs a pearlite based structure. Ok enough of the technical parts, what does this mean to you? What it means is that that 4130 likes to be cooled down slowly from welding temperature, or what we call a "cooling rate". Cool it too quickly and the base material next to the weld with have a VERY low fatigue life. This is a common result of the Tig process due to the localized heat input and cool shielding gas. Choice of filler rod has no affect upon this. This "hardness" can be altered with what we call a PWHT or post weld heat treat, and can be as simple as a localized tempering/stress relief with a torch using a proper method. Also with this due to the materials somewhat sensitive nature, larger fillets that flow smoothly are much better for fatigue. Larger HAZ (heat affected zone) bears no impact upon joint strength or fatigue life....none. The same strength calculations are used for both a properly performed Tig weld, and a Gas weld since both have areas next to the weld that are annealed. So in the end, provided you use the right process (process meaning fitup to pwht), either process will give you the same(ish) mechanical properties. Gas welding tends to be much more forgiving of process variation, and naturally forms correct size and shape fillets, Tig tends to allow the user to make undersize and incorrectly size fillets, and can cause serious problems in the base metal that need to be dealt with after welding.
Originally Posted by subnoize
We are here to learn from each other so don't be afraid to ask questions.
To comment on your most recent post, in gas welding the heat affected area will be greater than in TIG, and this is a good thing as there is a school of thought that says becaue the heat in TIG welding is so concentrated, that it results in stress in the welded joint that should be relieved with gas heat after every cluster on the aircraft has been finish welded. This is an un-going debate with some saying TIG is better, others saying Gas is better.
If you want to get a set-up for minimum dollars that will do the job, then I would get a gas set-up with a couple different size tips, and lease a pair of tanks. It will do anything you need to do aircraft-wise. If you go with TIG, you will pay more for a set-up, and still have to rent a tank for Argo.
If you plan non welding gas tanks, etc. Some guys can weld aluminum with gas but I don't have a clue how to do that. Aluminum takes more skill to weld with TIG also. Chrome-moly welds up really nice with either gas or TIG.