Next, we reattached the tubes to the flange, welding one fully from the outside, and the o
All that was left was for us to attach the collector. We borrowed a trick from Ron Covell,
We were about to weld the collector on when we realized that we needed to fill the space i
...We welded in a small square of 16-gauge sheetmetal and cleaned up the openings of the p
Finally, we used our MIG machine to weld the collector on, partly because it makes a wider
*Clean the weld areas thoroughly. The wire brush on our angle grinder did a pretty good job of cleaning the rust and old paint off the header tubes, but it still left stuff behind. Any oils, paint residue, or rust can cause scaly, porous welds. In an exhaust system, this can cause blowouts, but in a structural piece, like a rollcage, it can cause total failure at that joint. Take the extra time to clean all the joints until they are shiny. The pros use separate grinding wheels and wire brushes for the different metals they are working with.
*Make your joints as square as possible. It's much easier to weld two pieces of metal that meet together with no gaps between them. Take extra time figuring out the angle you need to cut to make the pieces fit flush.
*Use smaller bends to make better transitions. You don't have to admit it to anyone, but look at how some of the import guys make their exhaust systems. Some of them use nothing but straight pipe cut into hundreds of pieces at really shallow angles to make all the bends in the system as it travels from the headers back. That would involve a lot more welding that even the average enthusiast would want to tackle, but for headers, especially in a naturally aspirated application, make all your as bends smooth and gradual as space permits.
*Test your heat settings on scrap pieces first. It's less annoying to blow holes through junk tubing.
*Practice your technique. It takes a lot of practice to make good-looking welds. Practice as often as you can.