What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Pin holes in paint

Charles in SC

Well Known Member
Hello all. I recently took my cowling, wheel pants etc. To a painter friend of mine and had him spray them with some epoxy primer. It was a brand he recommended and he has been in the business over 30 years. After he sprayed them there were pin holes everywhere. I know very little about painting other than house paint of which I have used hundreds of gallons. Is there a fix for this or do I need to sand it all off and find another painter.
He said it was because my fiberglass was so rough but he did not say anything about this before painting it. This is just mainly a protective coat until I can get a real paint job.
 
Do a search on here, many post on just this matter. You will need to sand a little and apply some type of thin filler to close all those little holes before you can paint. Common problem, just needs to be dealt with. You should have dealt with the pin holes before the painter and if your painter was familiar with glass components he would have filled them in himself.
 
Thanks Ron for the reply. I worked for months off and on doing what I thought was pin hole filling and thought I had them done. I am not convinced that these were caused by pin hiles in the glass. It looked better before he worked his magic on it.
 
pin holes

Charles,
This is a common problem for sure.
The pin holes are hard to see if you are sanding and patching etc.
When I think I am done, I wash the part with water at a hose or faucet.
Let dry and spray with hardware store primer. The primer will show you any defects of pin holes....Repair, sand wash repeat until it is perfect. Then you or the painter can sand the last coat before repriming with professional primer.
Hope this helps.
 
Evercoat

I use Evercoat Polyester Glazing Putty to fill the inevitable pinholes. I apply it with a single-edge razor blade. It dries in just a few minutes.

Out of pity, I should give you the whole procedure. See, I had to go through all this on an entire airframe - it almost broke me - but here's the deal: On bare fiberglass, after prepping the surface, you need to start with a high-build primer. You should either use a small roller or a squeegee on the first coat. That forces it into all the cracks and crevices and supposedly fills the pinholes...but it doesn't. After you have sanded all of that off, you use a bright light to look for pinholes and you will find more. Fill them with Evercoat, sand, and reprimer. Sand again, and you will find more pinholes. Go through the same process over and over until you can't find any more pinholes or other defects, and the surface is smooth as a baby's butt. Then and only then do you spray the final primer coat and top coat. It's a PITA. I feel your pain.
 
Last edited:
Pin holes

Evercoat Glaze compound works great. Even if you prime first the pin holes show up better and you can apply glazing compound. "glaze" is key word. it is very fine and fills the holes.
 
On smaller pieces I did up to 7 skim coats with straight, heated epoxy. I looked for another method for the cabin, doors and cowling. What I ended up doing is a single skim coat worked around for a bit with a bondo spreader. Post curing I lightly sanded and then applied 3 coats of UV Prime. UV prime seems to just be really thick paint, or paint with a filler material in it. After those three coats I let cure for weeks... yes weeks, just did my cowl last week and won’t sand until next week. This ensure all is dry before I start sanding.

I block sand really most of it off. What’s left is pinhole free, smooth finish. I used the cheap paint test to look for pinholes and couldn’t find any, so hoping it works. My hope is the painter will have to do very little prep. The bonus is before prep I have a nice multicolor pink/black/white finish.
 
Last edited:
primer

I have used a filler recommended by vans called poly fiber UV prime. It is water based and needs lots of stirring reminds me of watered down sheet rock mud.
Put it on with a foam brush. Multiple coats. Sands like sheet rock and fills great. You can find it at Spruce.
 
Back
Top