Ox Ac or Mig for welding thin metal

[chuckinnc]

I find the need to weld thin stuff alot these days, maybe because everything is made of thin metal now. I have a Ox/Ac that I use to cut metal sometimes, Im looking at a mig welder with tank to weld thin metal, I have a 225 amp ac welder for big stuff.
I don"t know which would be better for thin metal, buying a mig and tank or learning to weld
with the Ox/Ac I have now. Which would do a better job on thin metal?
 

[Inno]

I think the MIG would probably be better because to make a good weld with oxy/acetylene you need to heat the metal up quite a bit which would tend to warp it. With MIG you do heat the metal up but only for a small burst. You can still easily warp sheet metal with MIG but the trick is to move around as you weld, make spot welds a good distance apart then fill in between them.
Others may have their preference but I would prefer MIG.
 

[old]

Mig or tig either one work real well on the thin stuff. As for learning to do mig if you can stick weld then you have nothing to learn. I did stick welding for years and when I applied for a job doing mig welding I walked in took there welding test and was hired on the spot. If you think about it muffler shops weld thin stuff and they us mig by the way
 

[wisbaker]

I'd vote for MIG/TIG, oxy acetylene on thin metal is a lost art. I see folks doing it a EAA on sheet metal work for experimental aircraft, but a lot of that is aluminium.
 

[NCWayne]

If your needing to do alot of thin material, like on cars, then MIG is the way to go. For all around something that will run .035 wire is great. If your planning on doing nothing but sheet metal then you can go with a smaller machine as .023 wire will be the way to go. Case in point, I helped a buddy do a little bit of body work on a 57 Chevy the other night using my MIG machine. Even the 'thick' metal on it didn't like my welder as I run .035 wire on it. Problem was I couldn't turn it down enough to melt the wire and not burn through the metal being welded in some spots. Having done alot of sheet meal over the years I was able to make it work for the most part, but there were still a few burn throughs (or bondo holding points...LOL) in the finished product where corrosion had made the metal so thin that I really don't think anything would have worked. Given what he's doing with it though it was just fine like it was and he was happy with the results.
 

[Puddles]

If you really want to get serious with welding thin material be it Mig or Tig, get a machine with pulse.

http://youtu.be/WTiCxszwW4I
 

[Lanse]

Id recommend MIG welding for you...

O/A is S L O freakin' W. Aganizingly slow. It puts a huge amount of heat into your metal and warps the crap out of thin material, plus the gasses are expensive and above all, its super SLOW. This being said, it is cool to play around with just for the heck of it...

TIG is a great process, but takes huge amounts of practice to learn. Im still not very good at it. Plus, everything must be super clean, absolutely ZERO tolerance for paint, rust, grease/oil, milscale, etc. Plus a good tig machine will set you back $2000-$3000 and up, new. Its also pretty slow, but still 10x faster than O/A.

MIG is like using a hot glue gun for metal. It burns right through millscale (but still cant do paint/rust/grease/oil) and is the easiest process to learn. For general fabrication I dont think it can be beat. A good 110 volt machine can be had for $500-$600, but I would HIGHLY recommend stepping it up to a good 220v machine. A Hobart 140 will top out around 1/8" maximum thickness under real world conditions (and only for short amounts of time), but its big brother, the 187 (like I have) can run 1/8" all day long, and up to 1/4". My 187 was $727 new, but now its called the Handler 190 and is spool gun capable.

Let it be said that ANY of these processes will blow SMAW clean out of the water when it comes to welding thin material.
 

[MarkB_MI]

I have a MIG welder, but I prefer to use acetylene for thin stuff. If you're repairing a small crack, the MIG gets done so fast the base metal hardly has a chance to warm up. MIG leaves a thick bead that is very difficult to grind down. With gas, I can take my time, get good fusion and end up with a nice flat bead.

I find it humorous that many folks who extol the virtues of TIG over MIG would never consider welding with gas. Yet with steel, the gas and TIG processes are almost identical, the difference being that when you're gas welding you use the inert gases in the flame rather than argon to shield the weld.

For aircraft work, gas and TIG are considered equally acceptable, and MIG is seldom used. The main problem with MIG is the "cold start", where the start of the bead doesn't have good fusion because the base metal is cold.
 

[Puddles]

Mark, a lot of people brag about this easy grind wire. I've never used it myself.

http://www.esabna.com/us/en/products_catalog.cfm?Product_ID=1082
 

[Bret4207]

Oh Lanse, you young guys have it so easy! When I started in body work it was oxy or nothing and I was trained by a guy (my FIL) who'd started int he days of gasoline blow torches, soldering irons (3-5 pounders, not electric) and lead! Oxy brazing was worlds ahead.

In the words of that great philosopher Goober Pyle, "Speed, speed, speed! That's all they think about!"
 

[Pops1532]

Those that don't like O/A probably aren't proficient at it. If you're good at O/A welding it will cut down on the learning curve with TIG.
For most guys MIG will be the best choice for welding sheet metal. Not necessarily because it's the best process, but because it's easier.
 

[Lanse]

Idk Mark, I'v yet to meet a "hard to grind down" weld bead. A good, powerful 4.5" grinder with a quality wheel can make easy work of that job, and a few seconds with a flap disk can make it look like the repair never happened...

Id personally say the differences between TIG and OA are:

Tig gives more control (especially with a foot petal)
Tig puts less heat into the metal (hotter source of heat, but its much more precise, and requires no pre-heat)
Tig is faster, much faster.

But, each to his own.
 

[Stan in Oly, WA]

Hi Mark,

The nature and source of the shielding gases in the two processes are largely inconsequential to the user during use. I'd say that the main difference between oxy/acetylene and TIG is the temperature of the heat source. Electric arcs exceed 11,000 degrees F, with oxy/acet being about half that. It makes a tremendous difference in how much unwanted heat is transferred into the work.

Stan
 

[Pops1532]

[MarkB_MI]

Well, Lanse, if I had a TIG welder I would never use gas. But I don't, so I have to choose between OA and MIG. Which was the original question.