How to fill in exterior paint on plywood

Question

I have a wooden garage door that I'd like to paint. It has been painted before, and the old paint had been chipping and flaking off.

I scraped off as much of the old paint that I could, and then I sanded with medium grit, and finally washed the area with a high-pressure hose and let it dry. After I did this, there are areas where the wood is exposed, but around them is the original paint.

Then I painted my new coat, but the areas where the chips were scraped off are still very apparent. The area around those chipped areas is much higher and it looks bad.

Should I put more coats on, or will that not smooth it out? If not, should I try some kind of filler, or do I have to sand all the old paint off so that it will have a nice, smooth finish?

Answer 1

Additional coats will not help much. The key would have been to use a heat gun or chemical stripper to remove all the old paint, or sand the areas where bare wood and remaining paint meet until the surface irregularities were minimal.

You could try using a taping knife or wide putty knife and spread a layer of exterior spackle across the whole surface, then sand smooth. This is a bit of an art and if you aren't practiced it could end up being a lot of trouble/work. If the paint you already applied has a sheen it would not stick well anyway.

I think you know the answer to your question... it was your last mentioned option (except I think you should consider a heat gun).

Note: higher sheen/gloss paints will tend to exaggerate surface irregularities whereas low sheen can help hide.