What is the proper method to apply a coat of polyurethane over bare wood?

Answer 1

The best solution (fastest and most durable) for protecting woods, is to use the old masters technique: apply 3 to 10+ very thin coats of glossy waterborne polyurethane (also called polyacrylic) and then apply 3 to 6 very thin coats of satin waterborne polyurethane.

For each coat: apply a thin layer of the polyurethane, do not have too much on the brush and just apply it in one stroke, do not over work it. Thin coats allow trapped air bubbles to escape easily. Working the polyurethane with the brush is what causes the bubbles. The thin coats dry in 1.5 hours in ambient room temp air, this time can be reduced by using a blow drier or shop-vac. Once it is dry sand with a very fine sandpaper, like the 3M Sandblaster 320 grit. Blow the dust of the surface and wipe with a slightley damp (water) microcloth. Make sure the surface is dry and clean and then apply the next coat.

Why use this method?

Be very patient, the thin coats will give you an amazing end product that does not have streaks or bubbles in it. The end finnish is very close to a satin finnish, but has a wonderful depth to it because of the gloss underneath. The gloss is used because it is much stronger, if a stronger finnish is desired use more (10+) coats of the gloss polyurethane and then apply the satin coats until the desired finnish is achieved. The water-based polyurethane is used as opposed to the oil-based, because is dries much faster (hours compared to overnight), is easy to clean up with water (instead of mineral spirts), is less liley to damage brushes, and does not amber/yellow the wood like the oil-based does.