I have a 71 F100 that I'm trying to save from rusting out. i was going to clean up and coat the inside fenders, fire walls and under carrage with Por 15. Any opinions if the satin or flat finish protects as good as the gloss? I think the flat would look beter in the fire walls / engine bay, but am more concerned about protection strength. Thanks for any advice

 

Shouldn't be any difference in film strength or adhesion but I'd personally prefer the satin if trying to replicate the original factory finish.

For the max strength my POR-15 preference is their silver---its like 25% solid content. One that's in place almost any brand top coat finish could be applied for eye appeal.