I have always wet sanded my urethane primer with 400 paper before final paint, but have read some posts that recommend dry sanding..what grit do you use for the final sand before either a sealer coat or color coat? I sanded the first coat of primer dry with 220, and it clogged the paper some but not too bad, it was actually easier than I expected. I am going to fix a couple spots, put a coat of K36 on, and then do a final sanding.
What grit is recommended?

Dave,
Ive been dry sanding primer prior to paint for several months now.

I use 320 grit dry. If you keep an air hose near by to blow off the panel and block every so often you wont have any clogging issues with the sandpaper.

Once ready for paint I apply 1 coat of primer sealer. We use ppg products and the sealer we use is k6, mixed 4:2:2:1. Thats 4-k36, 2-DMD tint or 2021 clear, 2-DT reducer, 1-DCX8.

A few reasons why I like to dry sand:
No more sand sludge mess all over the floor that never comes off.
No more chasing water around the seems.
I can use my long boards vs those 5in or 9in blocks.
To me its produces a flatter surfacer.

Bascially it all boils down to what you prefer and works best for YOU...Eric