brassplyer

Using Omni high-build 2K primer - do you favor sanding between coats or do you build it up and then sand?

bfit

I rub back between every coat.
but I'm from the days of nitrocellulose lacquer,
Bfit

540 vette

Yes I block sand it.

71 Vert LS1

On my C10 project we did two rounds of 2K primer. First round sanded with 180 grit. Second round with 320 grit. Both block sanded with guide coat.

Sabre34

Yes.

71yellow454

Two coats of epoxy then 3 coats of 2K primer, block with 180 grit and repair anything I missed then two or three more coats of 2K, then block with 320.

DUB

Actually this is hard to read. I am not assuming anything....

IF you are applying your FIRST coat of primer and THEN apply the next coat WITHIN the flash time specified that will allow the second coat to bond to the FIRST coat....NO....you do not need to sand the FIRST coat.


NOW... If you applied 2-3 coats of this primer and it cured out.....then YES...you MUST sand it so the next round of priming....the primer will have a good surface to bond to due to it is NO LONGER a chemical adhesion bond....it is a MECHANICAL bond.

So...ANYWHERE you do not sand the primer....is an area that the second round of primer will not stick....and if it does...it will not for long.

So...after your second round of priming...ALL of that primer must be sanded so your sealer will stick MECHANICALLY to it. Because ONCE the primer is cured out....chemical adhesion no longer takes place due to the primer did what is was supposed to do....cure out.

DUB