Por-15 products ARE NOT EPOXY. It is a isocynated paint (Be careful of fumes) that cures in the presence of moisture. You refer to the “silver paint”, and I guess you meant to say the “TIE-COAT” primer. I think this is the ONLY product (they make) that is even close to being moisture resistant….Like automotive epoxy primer. It’s my opion, but ANY “professional only”acrylic enamel paint will work as good or better and cost a lot less. I have purchased their products and used them. I didn’t see any advantage in using them over the real refinishing products made by PPG, Dupont, Glasurit and so on. They do have a great marketing team!!!
PJ-1 paints- I buy & use these too and they ARE NOT EPOXY. I suspect they are also lacquer based. Try some lacquer thinnner on your rattle can paint after it has dried a good long time.