Michael Dresdner

straight talk about wood finishing

Gummy bear

Q: I’ve tried Zinsser SealCoat on wood turning as a sealer before wipe on poly. The finished result is outstanding; it did a great job of sealing spalted maple. For sanding, I use a 2″ disc in a cordless drill on low speed off the lathe with 400 grit paper. The sandpaper builds up with clumps which get deposited elsewhere on the piece. Would a lubricant help, if so, what?
A: Using self lubricated paper would certainly be a must, but two other things will also help. First, make sure the SealCoat is completely dry before you sand. If it is still soft, it will gum up paper quickly, creating clumps. Second, make sure your sanding speed is slow enough, and your touch light enough, that you do not melt the shellac. SealCoat, which is shellac, will soften at around 120 degrees F. It’s surprisingly easy to create that much heat with the friction of a power sander, especially with such fine grit.