Just to make sure:

The only way to GTAW weld aluminum is to use AC style tig welder?

 

I've never used TIG but I've done MIG welding on aluminum. TIG is just more precise and cleaner.

 

Yes you hyave to have A/C, with D/C pos. it ***** up tungstun. and with D/C neg(what you use for steel) I think just melts the **** out of it

 

Aluminum corrodes quickly and the corrosion has a very high melting temp.

AC functions to clean the surface of the aluminum.

 

there are a number of process that will work for welding aluminum. high freq AC tig being one of the more common along with mig. there are also coated electrodes made for stick welding and i've seen it done with a gas torch, but not real well.

 

weve tried at my work to do it with a torch, i know it can be done but no one could get it right

 

I've seen it done with mig and come out very nicely.

 

You can do it with a mig. You just have to set it to a/c. You can make it look good. But you will never make it look as good as tig. With tig you just have more control.

 

anyone try it with a stick welder? A/C?
just curious....

 

To answer the question, AC with a high frequency arc starter/stabilizer is the way it is done most often now, but is not the only way to do it. Originally TIG was called heliarc because they would run DCEN with some He mixed in to weld aluminum. You can do DCEP (and even scratch start), but it’s harder to learn. There’s a lot of people that prefer DC and some He for aluminum welds that have to pass some certs.

Aluminum can be welded pretty nicely with a mig, but you’re pretty limited with most mig welders. Most sub 200A welders will weld aluminum around 1/8” thick, not much thinner or thicker well… thinner is just too difficult to control for most people (to get what we’re talking about to weld you have to run these welders pretty much wide open power and wire feed setting wise), and thicker doesn’t work well, even with a weave or multiple passes because thicker sections of aluminum absorb heat too fast (you can work around this with careful preheat, but that’s one more step that makes it harder to do right)