Well, tungsten type and diameter does matter because certain type and diameters handle different amounts of amps. I did try cleaning the filler as well. The problem is definately in the filler type. Unfortunately my boss won't let me get any other filler manufacturer because we need to get these parts out on the fly.
Preheating definately helped (AWESOME SUGGESTION!), but I think I already contaminated the base metel so much with the previous weld that I was still getting a really dirty puddle when I tried to weld on AC w/ 1/8" 2% thoriated. I was set to about 250, AC balance on 7, HF maxed out at 100 Hz, and pure argon at 40 CFH. The tungsten was still melting and having a hard time with those settings.
I also thought that I may have preheated too much....does that sound weird, or is that possible?
Before I tried the preheating and AC welding, I had to mill off the old welds...I only left about .005 of the old weld on the part. Then I preheated, and then immediately welded. Came out very ugly. You could still see nasty stuff in the puddle.
I then decided to break the joint free, grind off all the old weld, relocate the plates, clean, preheat, and weld....still pretty ugly, but not nearly as bad. Just bad enought that It wouldn't fly though.
I spent half the day trying differnt things again, but ran out of time. The boss let me just use 4043 eventhough the weld will look black when we get it back from the plater because we need to get the part out. It's only getting clear anodized, so it won't look too too bad.
Oh well, thanks for the suggestions. I think if I could do it over, preheating is definately the key to success in my case. I should have done that in the first place and ran on AC. I think I would have a little problem with the tungsten melting, but not so much that I couldn't finish the parts. (that and a torch that can handle 5/32" or larger tungsten!)