What can I spray over 'self etching' primer ??`

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?

"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?"
I think they expect that the top coat will be another spray bomb paint.
Unless I'm just going to spray bomb a part, I quit using it, for the same reasons SPI mentioned.

I probably will do the same as you Old Buzzard... relegate the self etching to insignificant parts...

I really do not want to 'strip' these bumper brackets again, so I 'might' just sand them lightly and then apply 'GM Reconditioning black'; which I used for years to match the factory original 'semi gloss' black underhood and chassis parts. It is not a two part paint; instead is basically an 'asphalt' based paint (what I heard it called one time); it thins with mineral spirits.

I've been using this SEM direct to metal paint for lots of smaller parts for years. It has the perfect black sheen, flashes in a couple minutes, and after 3 coats it's ready to touch in like 15 minutes. It's not cheap at almost $20 a can , it's tough, so easy, and I can't tell which parts I painted with that or SPI primer, plus easy touchups. I've been through like 20 cans of it, and ready to buy more.
Attachment 11646

You should be able to put about anything you want over that self etching primer. I would refrain from topcoating with the SPI like you mentioned. I'm sure they have a good reason for saying not to. The rattle can paint would be fine or a catalyzed automotive paint would be fine. Just give the self etch a light scuff first if it's been up there for a while.

I had planned to put on Eastwood urethane chassis black (satin finish) over it... which is an excellent reproduction look to original underhood parts and chassis parts... so maybe I will do it if you think it will be OK. The SPI cautions could be just overdoing the CYA thing....?

Self etching primer is great for your rusty trailer that you're going to paint with Rustoleum or a similar non catalyzed enamel. It's for getting by - SPI is way too expensive for getting by.

Rick is that what you would recommend for my all steel 16 and 18 foot car trailers I built in 05 & 06 they are looking a little rough. Both are black.

Only if you want to keep repainting them every few years.

Awlgrip is some of the toughest paint I know of at the moment. Imron isnt much better than Nason anymore in my opinion.