What are sunken joints?
In preparation for a woodworking project that will involve adhesives, I'm doing a little research. I've encountered the term "sunken joints." What are "sunken joints"?
You're smart to do some research before you embark on your woodworking project. It can be discouraging to work hard for a professional appearance and then have unexpected "issues" with adhesives make your project look less than spectacular.
Sunken joints generally occur with water-based adhesives where the wood in the vicinity of the glue line swells, leaving a small hump. Sanding or machining across this area makes it flush. That's good, but unfortunately, once the moisture in the wood equalizes, the leveled glue area usually shrinks, leaving a depression. We often cause the problem by working with the material too soon after gluing or by not allowing the glue to cure thoroughly.
To prevent sunken joints, you can allow the glue to cure longer; use faster-drying adhesives; consider using less adhesive so there's less squeeze-out during clamp-up; and work in room temperatures above 70°F or consider a hot box (depending on the size of your piece) to speed curing.
Good luck with your woodworking project!
Copyright © 1996 & 2008 LAF/C.R.S., Inc. All rights reserved. The previous article,
in whole or in part, appeared in the September/October 1996 issue of
Woodworker's Journal.
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