Originally Posted by
aspeed
Could a MIG welder work for the steel mufflers? Lots of people have these at home to beg, borrow or steal or whatever, for a beer even. They are much cheaper than TIG and are ok for thin steel, I did some body work with mine on an old van. I made a couple of mufflers for glow, which runs cooler. Everything was a .001" press fit out of aluminum.
You can MIG weld thin aluminum but it would be a real chore .... pain in the arse would be a better description. I certainly wouldn't expect attractive welds unless you have a lot of experience. If I was making an aluminum muffler and I didn't have the proper equipment and knowledge to use it, I would pay someone to TIG weld up a muffler before doing it myself. I wouldn't even MIG weld thin steel as it is so easy to oxy-acetylene weld thin steel using a bit of filler rod. Note I say weld and not braze as it is a much simpler process than brazing along with being lighter and stronger. Any filler rod used goes 100% to the weld joint where with a braze, the filler material flows in a rather uncontrolled manner, unless lap or similar joints can be provided. The welds are also good looking with minimal to no cleanup required. Every corner on the muffler shown in post 20 is a butt weld and other than brushing off a bit of oxidation before paint, there was almost no other cleanup.