# Which welder should i use to build a airplane frame?

Discussion in 'Workshop Tips and Secrets / Tools' started by aircraftbuilder, Jul 19, 2014.

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1. Jul 19, 2014

### aircraftbuilder

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Hello I am thinking about building a airplane but it is a welded plane. What should I buy for a welder to build an welded airplane frame?

2. Jul 19, 2014

### TFF

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Oxy Acetylene if on a tight budget; TIG is you can spurge on tools. No MIG, No MIG, No MIG. OA is the classic way.

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3. Jul 19, 2014

### aircraftbuilder

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So tig is the one I need to buy. thanks

4. Jul 19, 2014

### Brian Clayton

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and buy a good one. Cheap ones have unstable arcs that are a pain to weld with.

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5. Jul 19, 2014

### akwrencher

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I can recomend the Thermal Arc 181i. Probably cost you about 1400 to set up new. Light, portable, and powerfull. I haven't used it for tig yet, but the mig and stick both have very stable arcs. Only down side is it puts out only dc, so you have to use the mig function to weld aluminum. Not an industrial unit, but great for a home owner. Digital display, knob adjustments, and only weighs 32 lbs.

6. Jul 19, 2014

### cklskypilot

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I would look for a good used water cooled tig welder with foot control that can also weld alum. Most of the home units can not weld Alum and most home units are scratch start and air cooled. A good used unit will cost 1500--3500 dollars. As for using a Mig welder. There are times that it is OK. But never on a structural support. and if you pre heat the area to be welded you will Not have a problem with the metal crystallizing. As for me. I would pick a gas torch outfit over a Tig welder If I only could buy one. A gas torch can be used for so much more. Good luck

7. Jul 19, 2014

### thump

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(WARNING) The following is from a person that's been told that he has an odd outlook on life. Buying a tool or a piece of equipment is a lot like dating people or marrying them. (DATING) Try out different types of equipment and see what suits your taste, it may cost you a few dollars but you'll end up with something you like. (MARRYING) You'll take other peoples word about it, buy it, tell yourself you can get along with it, hate it, do what ever it takes to get rid of it and it will only cost you money and possibly your project in the end. P.S. Yes I'm still married

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8. Jul 20, 2014

### proppastie

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I have welded Oxy, Tig, Mig, Stick, and Braze, The first two on aircraft. I consider myself passable, but not pretty (welding that is). Everyone says Tig is best, and I do not doubt it but for arguments sake do we really have hard test data (papers, references etc.) that show for thin wall aircraft tube it is stronger?

Last edited: Jul 20, 2014
9. Jul 20, 2014

### TFF

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It is stronger in the fact if done right, less of the tube is affected in heat and a more consistent bead. The argument comes in at "done right" Done wrong and you can make the tube brittle at the weld. If not, O/A is a better choice. O/A if done right has an auto stress relief. I find TIG is easier not to burn through or overheat. I find it easier to jump in O/A when I have not had a bunch of practice. I dont weld a bunch in the grand scheme of things, so I have to practice whatever discipline before I jump in no matter what. The right answer comes to, Is TIG best, No; is O/A best, No.

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10. Jul 20, 2014

### cheapracer

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I broke out my TIG the other day and did some 'braze welding' with some bronze rods (not to be confused with 'brazing', stupid British English).

I haven't done any Oxy/Act brazing or braze welded since my apprenticeship (although TIG is technically brazing) so first time I have tried with the TIG and worked out well, no reason it shouldn't really, it's just a flame of a different source.

11. Jul 20, 2014

### dcstrng

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For the weekend hack (me) it is hard to justify the high-dollar machines unless you plan to do more than weld one airframe. OA is just fine and you can get a super-system for $500 (plus tanks gas etc…) and a lot less if you economize, they are; adaptable, pleasant and always works… That said, I’ve recently added an offshore-made TIG and my welds improved almost immediately – I’d waited months for that magic used Miller, etc., to come on the market -- fantasy… Most of the established suppliers of China-made TIGs are well aware of the uphill battle they have competing against Lincoln, Miller and the other established industrial-quality machines and they seem more than willing to back their products, should a failure occur… Shop for the features you need and forget the rest… so far I’ve not had to test the customer service of mine… Even so, for general welding I don’t use either – I’ve got a little flux-core HF welder I picked up about 3-4 years ago thinking it would probably be junk – never missed a beat with mild steel, about as hard to use as making a peanut butter and jelly sandwich, and other than typical flux-core spatter it works… Still if I was on a strict budget and need the be-all-to-end-all welder for 4130, it would be OA – they’ve welded a gazillion aircraft… 12. Jul 20, 2014 ### akwrencher ### akwrencher #### Well-Known MemberHBA Supporter Joined: Oct 16, 2012 Messages: 1,071 Likes Received: 369 Location: Gustavus, AK OA is very handy, and you can use it to "stress relieve" your welds. Get a cutting tip, and a "rose bud" tip". you won't be sorry. If you have extra money to burn, get a tig and learn to use it. They are like OA welding but with electricity. Very nice. A foot pedel control is very useful. dcstring likes the flux core wire. Personaly, I don''t. Not because it doesn't work, it does. I just like the clean welds that real mig produces. No slag to clean to speak of. CO2 is cheap. For tubing, get Oxy torch, and if you have money, get a tig too. Versatility is nice if you can afford the tools. dcstrng likes this. 13. Jul 20, 2014 ### BJC ### BJC #### Well-Known Member Joined: Oct 7, 2013 Messages: 9,118 Likes Received: 5,925 Location: 97FL, Florida, USA If you go to Oshkosh, you can try both OA and TIG, and see what you like. At some point, you will need a torch for heating / bending tube and fittings, so consider that aspect. At Oshkosh, you will also be able to get some experience with wood work, sheet metal work, fabric work and composite work. Many certified aircraft have been built with TIG without "stress relieving" or "normalizing" the welds. If you buy OA, be certain that it is an aircraft torch. I have a Victor OA aircraft torch, but an old Smith is really nice. BJC 14. Jul 20, 2014 ### ekimneirbo ### ekimneirbo #### Guest When buying a major tool, most home builders have trouble convincing themselves that the more expensive option may be the best value. Many airplanes have been built using OA torches. Most of them have welds that look like a flock of pidgeons flew over and made the deposits.....but they seem to hold up well even if they aren't things of beauty. It only takes one bad weld even if all the other ones held up. No matter whether you use OA or Mig or Tig, you need to practice and make good penetration. An OA setup is not as cheap as it would initially seem. Yes you can rent tanks, but its just deferred cost that ends up being more expensive. Buying your own tanks is best, because at the end of your interest in using them, you can recoup most or all of the initial cost of purchase. 20 years from now they will probably be worth more than you paid for them. Mine were. You need a small aircraft torch and small hoses for a nimble touch when welding thin tubing. This is usually hard to find used and most of the torches available second hand are too large for best welding control. Total up the cost of these items and a cart,guages,small hose,spark arrestor and the cost of rods to weld with and you will be pushing the envelope for a Mig welder. Many people say you can't use Mig to weld an airplane. I think its either Maule or Rans and probably some others who do just that. Whatever you buy,get a NAMEBRAND. When a cheapo stops working, it has no value and often no source to get it fixed. Buy a quality welder and it will be worth u of its cost 10 years from now. So its only an investment over time. I recommend Miller. I used to like Lincoln and they are still OK, but when buying my last machine I found that there were small things that converted me to a Miller. To me they are like 1, and 1a in choosing one. If you can spring for one of the higher dollar Migs, they have Pulsed arc....which allows finite adjustment of penetration/cleaning. If you can't get the cash for one ($5k) then step down to a 212 Miller. It has an easy adjust dial based on material thickness and can be bought on Ebay and shipped to your door for about $1800. My son has one and loves it. TIG Its great and allows control of heat and fine beads when needed. Yes it costs more, but you'll love it after a little practice. My suggestion is to get one of the newer Miller Dynasty units with the Pulse control rather than buying an older transformer style machine. Its more compact, and much more versatile. Yep, it ain't cheap.....but the best never is. Lets face it most people go with OA because its cheaper than TIG and they are often intimidated by thinking they don't know how to use it. BEFORE you do anything, invest$40 in a Ron Covell video on TIG welding. If you decide to go with TIG you will probably keep the video and watch it ocassionally to pick up tidbits you missed the first time
around. If TIG is not for you, then sell it on Ebay for half the cost, and know that you at least made an INFORMED decision. I actually think the advanced video is a better one to get . Also the tubing video is very good and will help no matter what type of welding you want to do. No, I'm not affiliated with them and have neve met the man.....I just find these videos very helpful.

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15. Jul 20, 2014

### TFF

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I know Champion, like Citabrias, Decathalons, and Kitfox use MIG. They also had a big learning curve because for years the welds would crack until they perfected the process. Each cluster takes a precise amperage; not a generic get it done amp. One extra tube, one tube thickness change, one diamiter change and it will not weld through to aviation standards. It will look pretty, but be as strong as mud. If you can come up with the perfect amperage everywhere, go for it. With the TIG you can see it in action and that is why you play the foot pedal. Being electric, TIG has the same amperage problems but you can adjust in the fly. Nothing wrong with OA; there will always be more airplanes flying out there with OA. Crush all the rag and tube airplanes including every homebuilt before the 80's and the others might have a chance.

16. Jul 21, 2014

### ekimneirbo

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While I readily admit that I am far from being an expert welder, I have found that its often difficult to get the beautiful weld I always want with a Mig. What I have found is that if you are going to be welding the same thickness of material continually, you will find a setting that lets you weld consistenly. When welding things with different thickness (or extra mass) I try to make my torch place most of the heat in the dominent part and move it as if I'm spreading from the thicker part to the thinner part. In other words, most of the heat is applied to the thick part and a quick weave to the thin part. Even with clusters, due to the thin nature of the material, I would think that only a slight adjustment would be necessary. Obviously anyone wanting to weld this way should make a few similar clusters to practice on before going for the real finished product. Once someone has set their machine up for the thin material, I think they would have minimal problems with making repetitive quality welds. Again, as you mentioned, TIG provides the ability to adjust on the fly while making a weld. OA applies a lot of heat to a large area in order to weld, and may have an effect on material strength after it cools........but there doesn't seem to be any problems caused by doing so.

17. Jul 21, 2014

### dcstrng

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Heat control surely seems easier with the TIG (foot-throttle) with a smidgeon of practice – no doubt about it, and there is a fair amount of carry-over from OA skills… What little I know about `lectronic welding I learned (if you can call it that) stick welding on the old Lincoln buzz-boxes a gazillion years ago – all my boyhood friends grew up on farms and knew how to run a bead before they were out of diapers (I was from town and was always envious).

For some reason I have a mental block about fiddling with gas regulators cuz the only reason we used gas when I was a kid was for cutting -- so if I must turn on gas of some sort, then TIG seems worth the hassle (I’m probably the only guy on the planet that thinks so, but then that is 100% of the folks at my shop…:ermm. Never have had an opportunity to try MIG, but from what I read its use on aircraft 4130 would probably demand more skills/perseverance than I have…

OA is pretty good, but requires two regulators so I guess I don’t use it as much as I should (have a Smith Little Torch I use for truly light stuff – and this is what is usually stays hooked to the gas), and the TIG has only one switch and one regulator… switches and foot “throttles” are about my speed. I agree flux-core is messy, spattery and not show-quality… but for tossing a quick jig or helping-hand together, works for me (one switch… throw on the helmet and done…).

I have a bucket of Covell’s DVDs – handy stuff; only complaint it he shows more of what can be achieved than exactly how to achieve it (which for weekend hacks – me -- is often the most important…)

18. Jul 21, 2014

### aircraftbuilder

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Going to Oshkosh and already planning on doing that, thanks

19. Jul 21, 2014

### aircraftbuilder

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Thanks guys for everything. Hoping to go to Oshkosh this year and try out the welding classes and see which one I like best. thanks a lot.

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20. Aug 11, 2014

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