It's a worthless reply. In 1978 some rattle can stuff had just come out and it was suppose to keep the tubes from turning blue. I don't remember the product and I don't know if it worked because I had a monument guy sand blast the chrome off my Vance & Hines 4 in 1. I rattle canned the inside and rattle canned the outside with some high temp flatblack rattle can and never looked back.No one can do the inside properly, the problem lays in the prep, you can easily spray the inside of a lot of exhaust parts, but if the surface finish is not prepped properly before applying the ceramic coating it will flake off.
Richard
Do you think electrostatic spray painting would make it a much better job, prep shouldn't be that big an issue with the materials available.
not arguing, just throwing some stuff out there for thought