Expert: William Forster - 12/24/2006

Question
Hey Mr. Forster,
I'm laying bondo over plywood (making funiture), and I want to paint the work with an aerosol spray finish. Are there any solvents or paint products I should avoid so as not to soften the bondo?
Thanx, Steve

Answer
Hello Steve! Body filler is pretty darn resilient stuff, I've sprayed over it with everything from lacquer primer to water born paints to acid etching primers. Just avoid pooling or flooding the wood with paint. That is probably a bad idea when working with wood, anyhow. To be sure, fill and paint a test panel then expose it to heat and light. See how it reacts after several days of exposure, and decide if the result is one that you can live with. Then you will know forever what combination of products work well together. I would choose faster drying paints and primers. Most automotive primers are designed to be able to be sanded and painted within 3 hours, and I wouldn't feel good about laying down some exotic materials that are wet to the touch for more than, say, an hour. Remember, this stuff is really designed to go over steel, but it has many characteristics of wood. It's very porous and It WILL sop water and other liquids, and hold them, just like wood. That is why bondo repairs sometimes fail on cars, water intrusion thru cracks and outright exposure to water. Bill