An Office for the House -- Complete With Woodworking Projects #7: Getting Close to Done With the Desk--- and a quick question...

Rob,

Like you, I have always been told – and never failed to heed this sage advice – that you need to sand between coats. I use 220 grit, sand lightly, and use a tack cloth to ensure all the dust is removed.

Without the sanding, the first coat has no “tooth” onto which to adhere. It is more critical with water-based finishes since the second coat cannot “re-emulsify” any of the carrier (solvent) in the first coat, and cannot therefor attach the two coats.

Least ways, that’s how I’ve been taught. That’s my story, and I’m sticking to it!

I’d be interested in everyone else’s opinions and experiences, since I’m yet to stop learning!

Good luck!

-- Dave; Lansing, Kansas

Sanding between coats is not about the look but about the feel. Unless you are doing your finishing in a ‘clean’ room there are dust particles in the air that settle on to the finish while it drys. Your hands (or fingertips) are quite capable of feeling these little nibs that become embedded in the finish. Sanding knocks these nibs down. The other reason for sanding between coats (particularly with finishes that don’t melt into each other) is that it creates a mechanical ‘tooth’ that provides for better adhesion between layers of finish.

-- criticism: the art of analyzing and evaluating the quality of a artistic work...

I agree with the sanding between coats advice. Poly binds to previous layer by establishing mechanical bonds much like velcro. So sanding between coats is needed to “roughen” the previously applied layer. This is not a vigorous sanding as you would do to the raw wood but simply a very light hand sanding with 320 grit to produce nearly invisible scratches in the surface of the finish for the next layer to latch onto.

-- With God's help all things are possible- even woodworking. Woodworking is not just a hobby, it is an (expletive deleted) expensive hobby.

Wow, those first three pretty much say it all and very clearly. I’ll keep it simple and say that sanding is necessary and you should do it.

Best of luck!!

-- Behind the Bark is a lot of Heartwood----Charles, Centennial, CO