Lincoln Welder

Hi,
I just recently acquired a Lincoln Precision 225 tig welder. I am getting ready to try it on aluminum. Can anybody give me an idea of how thick of a piece I can weld? Also how much current will I need for different thickness?
Thanks,
Ned

It just depends on how big the part is. any pre heat? I just built a pair of ramps to be used inside a race car hauler. 1/8 aluminum diamond plate 2' wide 16' long, 2" flange down on the inside, 4" flange up against the wall. welded to a 2x2 3/16 wall aluminum box tube frame and legs. No pre heat, 340 amps. you realy have to pour the heat to it when you have a lot of mass to soak up the heat. make sure your torch is big enough and has a good cooler. No air cooled torches on this kind of work. I welded for several hours straight without the torch overheating.

A lot depends on the part itself...thick but short, wide but thinner...like moonlight said, it really depends on the size. I would venture you could weld up to 3/8" in multiple passes, but if the part is too large, you won't even get that far. You can increase your capcity by using 50/50 Ar/He... or even 100% He, as the He ions help the electrical flow. I am not familiar with the Precision TIG machine, but if you have a wave balance, set it towards more penetration and preclean your parts really well. Degrease, scrub, dry, and alot of elbow grease with a new stainless steel wire brush will allow you to go to about 90% DC-. Preheating will also gain you a ton, I have used the Oxy-Act torch to blacken with Act, and then go to a neutral flame and heat until the soot is gone...not very scientific, but it works on non-critical stuff.

Steve

No way a standard transformer machine can get to 90% electrode negative. I do know the Syncro 200 can only get to about 40 % electrode negative.

On small stuff 3/8 aluminum is within reach.

I couldn't tell you machine settings, but preheating the whole piece will help you on thicker sections and help overall. the temperature that act soot leaves the aluminum is a bit on the highside. Off the top of my head it leaves somewhere around the melting point of aluminum. I would preheat to 200-300f which also help prevent weld joints from closing up on you.