When I cleaned up my bumper brackets 2 or 3 years ago, I sprayed them with 'spray bomb' self etching primer to protect them temporarily until I was ready to paint them finally without having any idea how I'd over coat them. Today I was going to spray some SPI epoxy and I thought I might paint the bumper brackets as well, but then observed that I had sprayed them lightly with the self etch primer for temporary protection. I recalled reading that SPI didn't recommend spraying their epoxy over self etch primer.

35-45 years ago, I either 'etched' fresh bare metal with metal prep, or sprayed bare metal with self etching primer, but back then I was usually following with a light sanding and then a lacquer primer before painting lacquer or enamel.

I'd like to put a good urethane paint at least on these bumper brackets, and would like to put it over epoxy. SPI says I should probably strip off the self etch primer first... What do you fellas say? Do I have any choice other than stripping it off? I lightly sanded a small piece today and sprayed it wtih SPI epoxy as a 'test case'... No reaction when I was spraying... but time will tell I suppose.

Basically SPI is saying there is nothing you can spray over self etch primer that probably will work... so why do so many companies sell it?