welding automotive exhaust

[Chubes]

Hey all, great site you have here!

I bought a Lincoln Weldpak 100(?) a few months ago to learn how to weld, and do small jobs around the yard etc, and I have a couple of questions.

I did a search on welding exhaust, and read that there are different typs of tubing used. I'm assuming regular tin, but also aluminized? How can you tell the difference, and what do you need to do to aluminized, to weld it, or can you? I want to cut the cat off my truck, 'cause I think it's restricting the flow, it's pretty quiet for a big block. I also read on another site that used exhaust store some of the gas in the metal, and explode if welded. Is this true?

On another topic, when working on my last project I had a problem with the gun kicking back at me slightly every 3/4 inch or so, and I can't seem to run a continuous bead. For anyone familiar with these rigs, I was running about 2 1/2 wire speed, on C voltage and I was butt joining 1/8 inch steel. I read that the wire speed in effect adjusts the amperage, so was I too slow?

Thanks in advance. I've been cruising the site for most of the day, and from what I've seen it's first rate.

Chubes

[Sberry]

You can wels aluminized pipe, its just the finish on it. I have welded hundreds of exhaust joints and never had one blow up and the only way I would think it may be a problem is with a flooded engine pouring raw gas in the system. I like cat,,, cleans up exhaust and keeps pipes lasting longer. I am not familiar with weld pak,,, but,, wire speed controls heat (amperage) and your stickout could be a bit long or you may need to up the voltage a notch. V is the intensity of arc,,, its kind of like turning up the temp a bit,,, wire feed is the amount. Its kind of like a bigger tip on a torch,, a real big tip puts out more BTU than a smaller one even though the flame temp is the same. V setting is kind of like turning up the flame intensity,,, not a lot more heat,,, just a little more intense. When its too low it will cause the wire to stub.