I was just going to comment on the oxy going south just as the metal gets hot, but somebody beat me to it <img src="/forums/images/graemlins/wink.gif" alt="" /> Those things are maybe useful for welding paper clips, but thats about it.

If you're looking for a quick/easy/cheap way to patch up an exaust system, bondo and fiberglass does wonders. A buddy turned me on to that trick, and I was amazed at how well it worked when patching up a buddies muffler. You grind the rusty metal down to semi clean, glop bondo on the mating surfaces, then wrap with 3-4 layers of matte cloth saturated in poly resin. Should be able to patch her up for $20-30.

As far as welders, I'm partial to the small mig units. I've had a miller 135 for at least a dozen years, and it is super versatiel for fabbing stuff, 1/4" thick is pushing it, but for 1/8" to 1/16" thick, it's the cat's meow, and it can be used with thinner stuff with practice.