Bubbles in Clear Poly Finish

Q: I’m having trouble with my finishing and wondered if you could give me some advice. Every time I apply a clear polyurethane finish, I get hundreds of tiny bubbles in it. I’ve tried different types of brushes and strokes and even mixing techniques, still have the same problem. Any advice you could offer would be greatly appreciated.

Rob Johnstone: Is your finish water-based or oil-based? If it is water-based, thin it 5 percent or so and then use a flat painters pad (with the short nylon bristles). If it is oil-based poly, thin it 15 percent and use a good quality varnish brush. They are not cheap, but they will last for years and years if you clean them properly. Don’t work the finish back and forth with your brush, try to just lay down one smooth coat per application. Personally, I am a fan of the wipe-on poly variety. It is easy to apply and lays down smooth. You just need to put a few more coats on to get the same degree of protection.

Hope this helps.

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