May Sales
How Long Can You Wait Between Sanding, Shop Cleaning and Spray Finishing
posted on by

Q: Is there a length of time that is too long between sanding your project and then spraying? As a weekend woodworker, I end up sanding my project and cleaning up the shed on one weekend, to minimize the dust, and spraying on the following weekend. Is a week too long?

A: No, a week is not too long, but less time is better. In addition to cleaning and roughing, sanding leaves exposed hydroxyl groups on the wood’s surface. They help bond with both finish and glue, but when exposed to air, oxidation closes these groups off.

There are a few problem woods, like rosewood, which exude resins after sanding. I doubt a week would be a dealbreaker even with them when it comes to finish adhesion. But I make a point of lightly sanding such woods immediately before gluing and, because glue and finish adhere in the same ways, before finishing as well.

One more consideration. Airborne dust will settle on the piece in a week: it should be removed. One alternative you might consider is to do your major sanding, clean up the shop, and then the next week, do a very light hand sanding with 320 paper. It will raise little dust, and you can quickly remove both it and any settled airborne dust with a lightly dampened cloth. For me, that would represent the best of both worlds.

posted on June 1, 2010 by Michael Dresdner
previous post next post
Leave a comment