Why not use stainless steel hardware?
Stainless steel exhaust hardware comes with many caveats. If the hardware doesn’t rattle loose it will weld together with no hope of removal. Here’s why: Stainless steel expands more than mild steel at the same temperature. When your exhaust heats up, the stainless hardware expands more and can come loose. Vibrations will cause the nuts to back off within a few miles. If stainless steel hardware stays tight, it’s stuck forever. Stainless steel is known as a “gummy” metal. When stainless steel threads are torqued together tiny balls of metal snowball in between the threads and literally weld the threads together. This is called galling and can only be avoided by using plenty of anti-sieze compound. Even with anti-sieze we don’t recommend stainless steel hardware. We include grade 5 zinc plated hardware with all of our downpipes. This hardware is corrosion resistant, but like anything will eventually rust over the years. Penetrating oil will help break them loose. They may put up a fight
