I've always wet sanded my primer coat (PPG DZ Kondar). I have only done spot repairs before and then only on an insignificant import (my wife's car) :D . I have found that I am able to see imperfections easier this way in comparison to dry sanding.

Now that I am gearing up for a complete color change on my beloved '68 Camaro, I want to do it right. Should I not wet sand the primer? Will the water soak through and cause future problems? My wife's car has spent years outside after repair without any problems showing up.

What is the concensus out there?
Dan

you can wet sand it, but only on the primered/steel areas, never get any filler wet.

what im doing is marking any bad spots before you take any paint off if possible. first we filled all areas to be filled, got those areas looking almost perfect with filler, then prime it all, i started with 180 with a long flexible pad in X-pattern, then the next coat of primer i am going to use 240 until the waves are out, then ill move to wet sanding with maybe 400, but with dry sanding after the 240 wears down(same as maybe 320) i can see a pretty good gloss as to where the waves and imperfections are. this is the way dream car garage was doing it, were trying it and its going alot faster than normal, the best thing for gettin waves out is the long sanding block, look in eastwood for a green one, has 3 rods you can take out to limit or allow more flexibility, really works good on the flat areas, making sure you sand in an x-pattern, keeping the block parrelell to the part, hope this helps, just another way of doing it - derek

When I was doing block sanding on my car I also found it easier to see little waves or imperfections after wet sanding it down with 400 grit wet. My garage door and walls are white and using the reflection off of the front wall with things laying in the garage it was easy to see what needed work but on the garage door it wasn't as easy. What I did was take some black electrical tape and attached it to the backside of the garage door in horizontal strips (about 6 strips 2" or so apart from each other). I pulled it tight after sticking the one end to the door so the strips were straight. I played around with the height of the strips so I could easily see their reflection in the car body.
I'm not a person that has done a lot of body work before but I still have a hard time feeling a very minor ripple but using the reflection off of the sanded down surface has helped out a lot.
Depending on how straight you want the panels to fit to each other you may want to block sand (using a long board) over the gaps between the doors, fenders, hood, quarter panels, roof, rocker panels, and trunk. I've seen a lot of cars that people sand the individual parts but when it's finished the body dips into the gap area's.
Jim

In my opinion dry sanding leaves a flatter smoother finish then wetsanding.
I work in a production shop and have been dry sanding primer prior to basecoat for about a year now. I find I get better results faster, easier, and much cleaner as well.

I block out my primer with 400 grit DRY then apply a coat of sealer over any primer spots.

Ive noticed several shops in my area are now also dry sanding primer prior to base.

The paper I use is 3M stikit gold sheet rolls. It comes in a roll 45yrd worth, you just tear it off to the size you want. The part number is 02590.

You might also want to consider stepping up to a higher quality of primer then Kondar. I prefer K38 or NCP271. Not a fan of k36 what so ever, primer quality DOES make a huge difference even thou most of it ends up on the floor...Eric