Welding Tips and Tricks

I found a Lincoln Square Wave 175 on Craigs for a great price, I know 175 amps isn't much when it comes to tigging aluminum but Jody's talked about a 50/50 argon helium mix to be able to puddle and weld pretty thick stuff. and I've some 3/4 in channel base plates with some 1/4 wall pipe sticking straight up, so its pipe to plate flat t-joint and a bunch of coped joints. I've got a jug of helium and wouldn't be to much trouble to hook up two bottles. All this stuff has been pre-welded with mig 4043 wire on 6061 t-6 and every weld is cracked or broken not me,somebody else.
So am I gonna need 50/50 to weld this stuff? because has to be strong ,any input remotely related would be great , thanks , John

I have a hard time thinking helium will help enough.

My last tig aluminum was 3/16" diamond plate to 1/4" angle and 1/4" angle to 1/4" angle.

I used 230 amps with straight argon and could have dialed it up higher for the 1/4" angle only joints.

Your 3/4" material will eat amps for breakfast.

Only trying it will let you know what will happen. Hell, go all helium and try it.

I'd say give it a go.

You can go 75% helium or maybe more before you have arc-start issues, and a good preheat will help, too.

Be aware of duty-cycle factors, as you'll be up against it with 175A until you get good heat-soak.

A recent experience with 6061 with a huge heat-sink area showed me you'll get better results with 5356 than 4043.

Steve S

Otto says preheat. With steel I break out either my rosebud tip, or if it's a loader bucket a big propane torch that throws a 4" diameter 2'long flame. I have a I.R. gun gives me a temperature reading. How do you heat aluminum? Isn't it hard to keep it clean enough?

I preheated my last bit of 1/2" work with an oxy/acet cutting torch. Put the heat adjacent to the weld on both sides (or in the O.P.s case, on the heavy section), but not directly on the weld zone. Then, wire-wheel or brush just before welding.

Steve S