by rossclark » Fri Sep 01, 2017 11:46 pm
Powder coat is applied on bare metal, you need it to be pretty decent to get a close to a properly done paint job. It can cover some imperfections (minor pitting) but not all.
I have some stove enamelled (old skool powder coat) steel parts, cowlings and such, that were done in 1990 and they're fine. I had alloy parts that were done at the same time and they were toast. On alloy particularly if any moisture gets under the coat, say from a chip, the alloy can corrode, go that powdery way and pit badly under the coating and you have no idea until you disturb it. Then it does come off in sheets / large chunks. I'm reasonably sure that the same might happen with steel in that it could rust out underneath the coating and you'd be none the wiser till it lost structure.