Technical Chemical stripper leaves behind primer on cast aluminum

I am stripping cast wheels and the paint stripper takes the paint off very well and does a quick job of it but it leaves behind the primer, and no amount of additional applications will remove the stubborn primer.

I want to remove the primer but also part of me thinks if it is stuck that well than just leave it but using 2K paint over enamel is probably not a good idea.

No don't tell me to just media blast because if I had that equipment I wouldn't have been using paint stripper!

 

If that primer is old enough, it might be heavy commercial/industrial quality primer/filler and may contain lead and/or other similar (toxic ?) substances, hence not coming off with commonly available paint removers and may require use of abrasive equipment/materials (sanding, scraping or "media blasting", etc).
Been there, done that.
If you decide to leave it, make sure to "neutralize" any and all paint remover residue that may now be embedded to it.

Or the "primer" could be some high temp cured substance, like powder coating.

 

What enamel are you referring to?

 

The primers that will stick to aluminum are sorta limited. If its an ugly green then it'd be zinc chromate. If the wheels are less than 25 yrs old then its unlikely they'd have zinc chromate as its been out of general use for that long. Zinc iron phosphate will also stick to aluminum. Both the ZC and ZIP primers are enamel based and should come off with stripper.

That leaves epoxy, and most strippers won't touch it.

 

If stripper won't harm the primer than 2K primer or color most likely is safe to use.
However I would apply a 2K sealer or a 2K sanding primer over it before color depending on how nice a finish you want.

 

I dont believe it would be a lead primer as the wheels are only 20 or so years old. It can be softened somewhat with lacquer thinner but I see myself going through gallons of the stuff and having to hand scrub the crap out of it to get it all off. I have done rounds of paint stripper followed by washing the stripper off and using muriatic acid to clean the bare aluminum which is what made me realize there is still primer sticking the the metal.

I think I may end up contriving some kind of tub to soak the faces of the wheels in lacquer thinner over night or something to try and remove it all.

 

It is just I assume a gray 2k primer. The stripper removed most of it but it has still clung to areas of the wheels and with as many days as I have cleaning up the wheels spending yet more days removing it by hand from those tiny areas will make me just quit.

 

I assume it would be enamel spray primer from an aserosol because I have refinished the wheels before but I dont know for sure if I stripped the wheels bare it was years ago. This time I will be using 2k auto paint.