Most of our tabletops are finished with polyurethane varnish. Polyurethane is the toughest, most flexible, least obtrusive, and most durable clear-coating available. It is resistant to water, alcohol, household chemicals, scratching, chipping, and wear. But its application is demanding and aggravating. A flawless surface is elusive. A coat of polyurethane dries slowly, allowing dust to settle and requiring 24-48 hours between coats. However, it dries too fast for all the little laps and strokes to flow and level themselves on a top large enough for dining. So we “rub out” the final coat to make it smooth and flat.
After the final coat dries for 48 hours or more, we wet sand it with water and 400 grit sandpaper. This removes the high spots, the embedded dust, the laps, etc. Then we buff with an abrasive pad.
In the photo below, you can see what we are looking for when buffing. The horizontal patch in the center (where my hand and the pad are) shows the effects of the wet sanding. The un-touched glossy varnish is broken up by the duller patches leveled by the wet sanding. It looks terribly uneven, but the highs to lows (glossy to dull) are only a few ten thousandths apart. Above and below this patchy strip, you see the result of the buffing.
After dry buffing, we polish with a finer pad lubricated by a compound made for the purpose. We can’t see what we are doing. We just guess when the sheen is even and all the effects of dry buffing are gone. These days, after drying and inspecting, we usually don’t have to go back to work over areas that are polished too little. Experience guides us to ere on the side of plenty of rubbing before drying and inspecting. Nobody likes to go back and do it again.
The final satin surface appeals to the eye and hand.
After rubbing out, the wood does not appear to be plastic coated. Short of educated scrutiny, the finish is indistinguishable from the oil finish on our chairs.