Tig: steel, aluminum, stainless

[farmboy weldor]

i know on aluminum for the amps you set 1 amp per .001 of thickness in base material, do you do this same thing on steel.

on stainless my teacher told me to run about 100 amps on 1/8 stainless( dont know the grade) he could do it without a problem but i couldnt get it worth crap, the bead was very small, it was a t joint and the face of the weld was only 1/8, he said i was puttin in too much heat, and ruining the "stainlessness" of the stainless so i dont know,

and with steels when i weld and dab the filler it always seems to get stuck alittle,what am i doin wrong or am i doing anything wrong?
and ive been trying the whole weave over the rod and just set the rod in the joint. i dont know why it just doesnt work for me.

thanx for any info

[Paul Seaman]

The .001=1 amp is a base line for most materials. On aluminum the material soaks up more heat so it requires more amps, stainless, and mild steels use less since the material doesn't conduct as much heat away from the weld area.

On 1/8"{.125** aluminum tubing I run around 130 amps and modulate from the pedal.
On 1/16"{.063** mild steel tubing I run about 55 amps and modulate from the pedal and 1/8" mild steel tubing I run 115 amps.

These are just the settings that work for me if you work faster you'll need more amperage or if you work slower you'll need less amperage. This is a practice and feel the difference area of welding that requires you to build some skill and trial and error to know what too hot or too cold looks like. Then you can dial up and amperage and just go for it, but you need to see the differences first, so you know what your looking at, and develope a mental picture of what the pool lookes like compared to the finished weld as an association. The only answer is practice, practice, practice!

Be well,

[precisionworks]

Like PJ, set Max Amps a little more than you think you'll need and work the pedal.

On heavy aluminum (3/8" and up, or large castings like an automatic transmission) my control is set for 200 amps, even though most of the weldment is run below that. On thin aluminum (below 1mm) I'll start with max amps set to 20, see if there's enough heat input, and gradually work up to where it needs to be. For work around 1/8", a 100 amp max works O.K., but the pedal is the boss - you only use what is needed, less as the work heats up, much less at the end of a bead near an edge.

TIG is pretty forgiving because of the real-time control of the foot pedal. Practice on lots of scraps first & you'll get a good idea of the heat input required.