my is frame painted with rattle can question

[original_balzer]

The previous owner painted the frame with rattle cans. After he had it sand blasted. My question is do I need to take it back down to bare metal or just scuff it up real well?

I know that rattle can paint is not as good as real paint. So is it going to cause a problem being under a product like por 15 and chassis black?

The PO said he put 2-3 coats of primer then there is 1 coat of stupid silver on the top.
Rustoleum is the brand he said he used.