I did some repair work on a heat shield for an exhaust manifold. Its for a rotary engine, so it is fairly small. The shield consists of an outer shell, insulation, and perforated metal to hold the insulation against the shell. The perforated metal was tack welded to the outer shell. I had to replace some of the outer shell using aluminized metal, and I soaked the perforated metal with rust dissolver. I now need to reassemble. I would like to coat the shell and perforated metal with something to prevent future rust, but I also have to make some tack welds. Would weld through primer work on both pieces, or will it get burned off by the exhaust heat? I have some high temp exhaust paint I could use but that would complicate the welding.