4130 Fab: GMAW, GTAW, OxyFuel

[Jim Heffelfinger]

Traditional aircraft tubing fabrication used OxyFuel but today we have other welding methods to chose from. What say you?

Edit: For readers confused : GMAW is the correct name for MIG and GTAW is the correct name for TIG (both no longer using exclusively inert gas) OxyFuel is the correct name for Oxygen with some other inflammable gas traditionally Acetylene

Modern electronics allows GMAW-P https://www.millerwelds.com/resources/article-library/an-introduction-to-pulsed-gmaw

[Sam Buchanan]

Traditional aircraft tubing fabrication used OxyFuel but today we have other welding methods to chose from. What say you?

The options include TIG, MIG, and holding the tubing over a very hot fire. I think the last option isn't very practical, but TIG is commonly used and I think the Maul factory uses MIG. MIG is generally not recommended unless very proficient and able to weld in a controlled environment (Maule).

But there is something almost Zen-like about welding a fuselage with oxy-acetylene. I found gas welding to be an enjoyable part of building the Legal Eagle and a skill set I have revisited since then.

[CraigCantwell]

Don't forget that standard old stick was used also during WW2. Unless you are going to be doing production, best to stay with O/A or TIG. If someone has run miles of MIG welds and can weld good enough to pass a code test, then it might be a possibility. Otherwise, I wouldn't bother with MIG. For a neophyte, O/A would be the best, as easiest to learn to do quality welds, and it would be the least expensive equipment costs. For the price jump between O/A and TIG, one could burn a lot of gas and lay down lots of bead before you paid the difference in costs. A typical builder is going to only build one airframe, and run a few hundred feet of bead during the process, so why spend several times the equipment costs on a perishable skill, unless there are plans to use the skills elsewhere.

BTW...for a cost comparison on just the basic set up for O/A vs TIG, no bottles included, O/A will run you about $750 for a quality setup, not shopping around or buying used. TiG is going to be around $2100 or so, for Miller or Lincoln equipment. There are a number of other brands out there, but one should do due diligence on them first.

[Mark Thompson]

What about wire-feed no gas. I learned to stick weld at Tech collage. Did very well. nice even smooth welds no voids. I bought both stick machine and a wire feed .020 and .030 wire. I am pretty good at that too. So what do you think about using the wire-feed to weld up frame?

[BoKu]

...I think the Maul factory uses MIG. MIG is generally not recommended unless very proficient and able to weld in a controlled environment (Maule)...

Also of note, Maule is using relatively specialized welding machines with real-time heat controls. It would be very hard to match their results with common commercial machines, and probably impossible to do using low-end boxes like the Harbor Freight units.

--Bob K.

[Sam Buchanan]

What about wire-feed no gas. I learned to stick weld at Tech collage. Did very well. nice even smooth welds no voids. I bought both stick machine and a wire feed .020 and .030 wire. I am pretty good at that too. So what do you think about using the wire-feed to weld up frame?

I wouldn't.

[Bill Berson]

I wouldn't use a Harbor Freight MIG welder, but my automated Miller 135 works excellent for me.
I have quite a bit of practice with the trigger pulse technique to control the heat on thin tubes. Without machine knowledge it could be difficult.
But that applies to all welding
The Miller 135 was $600, probably $700 now. I use Ar/CO2 gas only.

[Jim Heffelfinger]

Flux-core GMAW - not recommended for thin sheet metals. (<.080)

[Jim Heffelfinger]

Broad statements - RE: equipment costs - Miller indicates welding on one of their GMAW machines for 20 gauge mild steel at a .035 wire 80A/18v this is well within the capabilities of units costing under $1K - even down to $600. GTAW units are pretty close to that price point as well. GTAW does require lots of practice to get good welds (penetration). OxyFuel is low/broad heat (slow) and heavily heat soaks the base materials and penetration is usually good.

[Jim Heffelfinger]

https://www.youtube.com/watch?v=Is47-VwkyNg