mumblety-peg

My Feedback: (3)

This is my first time trying to paint a balsa plane. It's a Great Planes Patriot. It's glassed and pretty darn smooth. I wanted to keep it simple. So I'm using rattle cans of Rustolem.

It seems like 50% of the time, when I lay down the paint, I end up with a pitted area. That's the best way I can describe it.
The paint just seems to be puckered up. I've cleaned the surface wiht alcohol and I'm careful not to touch the surface.

Any idea what would cause this? Should I just spring for a paint gun?

Thanks
Mum

davidfee

Shake very well for several minutes, warm the can in a sink full of hot water, shake again (and frequently) and spray very light coats. Allow the solvent to flash off between coats.

Good luck... I hate spray cans.

-David

da Rock

"pitted area" sounds typical for a glassed area. Polyester and epoxy surfaces almost always have very tiny pits in them. You almost always have to prime the surface to get rid of them.

Have you read building articles where the author/builder mentioned, "primer coat, sanded almost completely off"? He did that to fill the tiny little holes that are really hard to notice when the glass is just finished, but will show up BIGTIME with a coat of shiny, opaque color. Those holes are why that author took the time to paint on a primer and then sanded it almost completely off. He sounded like an idiot, right?

mumblety-peg

My Feedback: (3)

I guess I did not describe it right. It's not small pits. Sort of craters. Like the surface of the moon. David's idea of warming the paint may help. I'm thinking it may be some inconsistancy in the paint.

I'm going to give the cans one more try. If ot happens again I'm just going to have to spring for a paint gun of some sort.

pmw

My Feedback: (1)

I have used Rustoleum paint for many years on my models with excellent results. I always use Rustoleum gray primer first, particularly over fiberglass. I sand the glass surface with 320 grit to etch it a little, then spray the primer as per the instructions. I usually spray a thin coat and after it dries, I fill imperfections with red auto glazing putty. After I sand out the putty with 320 grit, I primer again. I usually don't need more than the two coats. I let the primer dry for at least a day and then sand with 400 or 600 grit. Then I paint the color. The secret to the color application is to spray VERY thin coats. I let the paint flash for about 15-30 minutes between coats, depending on the temp/humidity. I've never needed more than three coats to cover the surface because the gray primer will stabilize the color blend and coverage. If you are going to two-tone, you will need to let each color dry for at least a week or you will marr the surface and possible peel the base coat with tape removal. I have used the "hot water" method to heat the paint with great results. But what many don't realize is that the aircraft surface must also be heated. In the winter, I will heat the spray room to heat the plane then TURN OFF the heat and paint with the heated spray can. USE A FILTER MASK!!!! A handkerchief over the nose is not good enough.

For what it's worth, I've used every paint known to man and Rustoleum was my favorite until.......I tried Nelson Hobbies System Three water based polyuethane. It is absolutely the best product I've ever used. And I've been painting models for almost 50 years.

Good luck,
Paul

bruce88123

Does he mean "fish eyes"?

mumblety-peg

My Feedback: (3)

Not fish eyes. I think heating the paint may do it. If not I'll post a picture next time it happens.

And my thanks to everyone.

davidfee

Not fish eyes or pinholes in the fiberglass? So are you saying chunks are flying out of your spray can to make these "craters?" Definitely warm the can and shake more, but other than that, I don't know.

mumblety-peg

My Feedback: (3)

This is hard with just words. Maybe I'm not understanding fish eyes. (There's an interesting sentence). I'll try posting a picture if it happens again.

davidfee

Here's a "worst case scenario" picture of fish eyes.

bruce88123

Sometimes reg alcohol won't get all of the contaminates off the surface and another cleaner/solvent must be used. This cleaner needs to be selected based upon what the substrate is made of (wood,metal,fiberglass). Don't want to eat up the material or destroy previous work. Denatured alcohol (lowerer water content) is better than isopropol but on some surfaces I even use toluene or acetone and then the alcohol. Must get ALL of the grease, waxes and oils off. Be very careful with these chemicals of course and use a lot of ventilation and hand protection. Once a prime coat is on you are usually OK.

toluene:
n : a colorless flammable liquid obtained from petroleum or coal tar; used as a solvent for gums and lacquers

checksix

My Feedback: (4)

Sounds like maybe he's trying to paint without priming first?