Originally Posted by Lizer
Would you wet sand body filler? My answer to that question is 'No,' which is why I elected not too. Apparently it's the same answer as Barry's. My fear is the poly primer absorbing too much water and not getting out. I think deadbodyman has actually discussed situations where it lifted when wet sanded. This clearly needs googled. I'd consider spraying 2k over it, blocking and wet sanding that but a concern of Barry's was having too many different substrates on there.
How long is long enough to breathe? After sanding these I'll be sealing in good time and I think it would be devastating to have that moisture trapped in there.
Of course you are correct about any moisture causing major issues if it got trapped. Have you considered dry sanding it with a coarser grit and priming with 2 coats of SPI Epoxy and then wet sanding that with 400-600? Most epoxies do not sand well but I used SPI Epoxy when I repainted my doors and then blocked them with 400 and a guide coat. It really worked well.
My fear would be first that it will take forever to dry sand with 400. Secondly, I am not sure you can keep it clean enough not to get nib scratches in it. I would want to do my final sanding wet even if it meant using a 2k or epoxy primer for final prep. As I already mentioned I am not the professional here but I certainly have experienced the situation you are in.
I painted a 47 ford in 1978 with Eliminator which was one of the eariest polyester primers. I know I wet sanded it. It is in the shop now getting repainted. The paint I put on it only lasted 45 years. Obviously the moisture did have plenty of time to escape.