I couldn't agree more- JBWeld is great stuff, but it's still a powdered metal reinforced resin product and is heat affected, and will out-gas for a time when heated to higher temps. We have Airborn Coatings and others in this area that do alot of NASCAR components, as well as my racing boat headers, and if we want a perfectly smooth finish with high heat aluminum/ceramic coatings, the steel substrate had better be pretty near perfect. We sand the daylights out of the pipes and get them smooth before sending them out for coating so the final finish doesn't 'telegraph' the imperfections thru to the visible topcoat. A boat buddy of mine had a set of well-used and -abused headers he sent over- they were pretty pitted from rust and neglect...'no problem' said the counter-monkey at the powdercoat shop, leaving Mike with the impression that they'd look brand-new when he picked them up. BOY was he disappointed...every pit and gouge was still visible, even more so now that the surface was coated and shiny. It was a lesson for me, for sure...

 

I love how easy it is for someone to say "no problem" when trying to tell you they can do a good job, and then you get the parts back and it's like they rushed the job or something. I gave these heat shields to my buddy's guy, and told him specifically to polish out or fill the scratches before he ceramic coated them. I go check them out a week later and I can see the scratches when looking up close. They are matte black, and the scratches are not that visible since they are on the bottom, but I still know they are there and that bothers me. We'll see what he comes up with this time around!

Thanks for your input guys...

D