TIG question

1 amp per 0.001" of thickness applies to single pass, full penetration, flat butt welds on aluminum and steel.

That also assumes a v-grooved joint on thickness above 1/8".

Yes you can weld 1/4" thick steel or aluminum with lower amperages, but it will take multiple passes to get your full weld.

It is easier to use a lower amperage on steel and do multiple passes than on aluminum. This is because of aluminum's initial thermal inertia. A little preheat with a propane torch can fix that though.

An inverter can skew these numbers on aluminum, because if you run the output wave frequency really high, you will get considerably higher penetration per amp of output. This can also be skewed by the AC wave balance.

If you choose to perform multiple passes on steel, you will need to wire brush, grind, sand or wire wheel the surface of each pass before laying the next one, or you will get contamination of your weld from the blue oxide layer on the previous weld bead.

This is not a problem with stainless steel or aluminum.

Thanks Ernie.

Great help!

Paul