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Have been trying to finish an oak coffee table with a satin Minwax poly. I have applied the finish with one of those disposable foam brushes that I always see Norm using. Problem is that the finish always dries with many small bubbles that become very noticable. I have tried to apply with both full strength poly (right out of the can) and a diluted poly (poly diluted with 10% thinnner). Either way I have the problem. I have also tried not to stir the poly before using but this is necessary to mix the satin particles through the finish.
I would greatly appreciate any advice so that I can get the last coat on properly.
thanks in advance
Joe
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Joe, all varnishes, polyurethane or otherwise, are challenging to apply by brush. At first I would have assumed that you had accidentally shaken the can which is pretty much a no-no.
At this point, I'd try a quality brush. Go to a good paint store and ask the clerk for the best brush they have for varnish. Take care of it and it will last for years (literally), so don't worry about the cost.
*I suggest ox or badger hair for your brush. High quality china bristle will work if that's all they have.
*Joe, don't spend another nickle on brushes. The bubbles are coming from air trapped in the pores of the wood. You could have wiped the poly on with a rock and gotten the same bubbling results. Brush quality has only a marginal effect on the final quality of a finish. And can shaking is a hoax preached to woodworkers by people who market finishes. Test it yourself. Shake the heck out of a can of poly and apply it normally to a piece of pine. Then take an unshaken can and apply it to the same piece of pine. The results should be the same. You need to seal the wood surface before appyling the poly. Polyurethanes have very long drying times. Because of this the air has a lot of time to try and escape, creating bubbles in the process. If you seal the surface with a fast drying product you can end the bubbles. If you can find a polyurethane sanding sealer try it, but a less expensive solution is dewaxed shellac. Make sure it's dewaxed or the poly won't adhere. If you don't want the shellace to impart color in your project use a super-blonde shellac. One or two coats will be enough. Then apply your poly over the top. Personally I would just finish the wood with lacquer, conversion lacquer or conversion varnish and be done with it, polyurethane is too much work. Good luck
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