[rahtreelimbs]

A few weeks ago I was welding on 1/4" aluminum. The parts were approximately 6 ft. long. Using my HTP Invertig I was using 220 amps with 3/32 tungsten (all i had). Fast forward to last night I was experimenting with 1/4" pieces 2" x 6" welding the 6" sides together. I was able to weld these at 185 amps using a different machine. Other than amps both were set the same expect using 1/8 tungsten on the smaller pcs.

Does the much larger material draw more heat out of the weld thereby needing more amps?

[MinnesotaDave]

Absolutely the case.

More mass = more heat needed for the same thickness. Especially for aluminum since it transfers heat so efficiently.

Mild steel not so much.
Stainless even less of a change.

[Troy Boy 72]

Absolutely the case.

More mass = more heat needed for the same thickness. Especially for aluminum since it transfers heat so efficiently.

Mild steel not so much.
Stainless even less of a change.

I totally agree with Dave on this but i also have found that stepping up to the next size tungsten ( 1/8 , 3.2mm ) for 1/4 inch material helps as well , seems to have a little more oomph in it for some reason, also dropping my ac frequency to 60 hz helps as well . this is just my opinion running an everlast 210 ext.
Cheers Troy