Sanding between coats of Poly

[Mark Bell]

Hello All, I am finally done with the mission style bookcase that I have been making for my wife. I already applied Minwax Provincial stain to it. Now I want to apply a few coats of Minwax wipe on polyurethane. The directions say to sand with 220 grit sandpaper in between coats of poly to insure adhesion. My question is, after I lightly sand with the 220 grit, can I wipe it down with denatured alchohol to make sure I get all of the sawdust off of it. Any advise will be appreciated. Mark

[Jim Becker]

Wiped on finish goes on very, very thin. Since you can wipe on your next coat relatively quickly, you don't have to sand it after every coat unless you leave it cure over night. Further, sanding, even with 220 grit abrasives can easily cut through the finish. When you do abrade...after a few coats are wiped on and cured, go very, very lightly. You just want to get any dust nibs off and lightly scuff the surface.

A better idea for the future would be to not use a polyurethane varnish...they are way over marketed as "the only" finish in big-box land, but are best left to floors, rather than fine furniture. Rather, buy a decent alkyd or phenolic resin varnish (Pratt and Lambert #38 or Waterlox, respectively by example) and you will not have the adhesion problem potential that poly brings to the table. Why use a finish that doesn't like to stick to itself and sometimes looks more "plastic" than clear?

[Todd Burch]

I agree with Jim.

Sanding between poly coats does not warrant a "clean room" approach. In other words, wiping down between coats would be a waste of good alcohol. Just hits the nibs, dry rag (or shirt sleeve, or air hose) off and on with the next coat.

Todd