Inductor Saturation

One way the windings will be in phase and the other will be out of phase.
You need the one that is in phase.

heard about that but i'm sure i followed the rule of thumb for inductance when i made the inductor. what i'm not sure is how to test it or how i would know if they are out of phase as i dont have a scope. how can i add an air gap in the inductor? do i have to change the core?

It will not work for a while and then saturate. It will saturate on every short arc transfer. We're talking a 100 times a second, not work for several seconds then saturate.

You have something else changing. Probably the wire speed is changing as it warms up.

As for the windings, to parallel them, you would need to have then running the same way. I.e. one side of each winding will go in the left side, connect those together.

The copper foil does not make a complete loop? I would leave it out.

the wire feed assembly is modded with a separate transformer supply. when the inductor heats up the sizzle changes to a machine gun sound. after cooling down the sizzle is back again. i don't see any difference when removing the copper sheet so i'll leave it that way to protect the winding from scratches.
as for the parallel i connected the two outer taps is it ok?

Not sure that saturation is the reason for the problem that you are seeing. However, to avoid saturation by adding an air gap: if your windings are on the central leg of the E, and all the I parts are stacked together making a block, it should be quite easy to separate them. Remove from the frame the two screws that hold the I parts , lift off all the I laminations, file the holes in the frame to allow for a gap, add a few sheets of mylar across the end-face of the E, reassemble.

when you say "..add a few sheets of mylar across the end-face of the E, reassemble" the I lamination is now physically separated from the E core. is that what you mean by that?

Yes, the mylar/plastic/card insulator provides the air-gap ( to prevent saturation ), by holding the stack of I-laminations about 1 or 2 mm away from the E-core, rather than these two parts being pressed tightly together.

ok now i get it thanks. Your right with the wire size it's too small to carry 100 amps. i can't find a thicker wire so i had 3 10g's in parallel for the internal wiring instead. now it's penetrating way better than it used to. also i find the positive rail more effective for the inductor. the sizzle and arc is more intense on positive while negative rail has a soft sizzle but a steadier arc.

Very interesting. When you've got the mod right, you should negotiate a bulk buy of 100 of these cheap AC MIGs, convert them to your super-modded DC version, and sell them yourself at twice the price...

lol i don't intend to sell. mine's to educate only..except for the inductor it cost me only about $10 to convert this AC to DC. it's not super-modded it's plain common sense mod. it's a straight full wave rectifier circuit + inductor nothing more. selling it twice the price is just sick greedy don't you think? very same reason why we have forums like this...