I’m wondering if wood movement will cause me any problems if I use glue (and brads) to join these two pieces of wood. See pic of scraps below — am running a casing-type trim around the edge of a shadow-box type of display. Can I smear glue all the way across the edge of the 5/8″ piece, and then brad the casing in place? Piece will be finished with Watco and poly.
forestgirl — you can take the girl out of the forest, but you can’t take the forest out of the girl 😉
Replies
Jamie, if its flat sawn then your probably ok but if its quarter sawn the thickness will change with the moisture content and the joint could break. Flat sawn will change from edge to edge and should not cause a problem. Also the wood should be from the same stick with the grain oriented so that they both change in unity. Well, thats the way it supposed to work, I think.
P.S. Got the website nearly ready to upload. I'll let ya know when its ready.
Steve - in Northern California
forest girl, you have absolutely nothing to worry about. lets say that your wood is @ 8% moisture content, and in a dramatic swing it goes up to 16% moisture content. the wood will only expand about .01"- .02". over the 1 1/4" length. now only 5/8 of that it actually glued, and 5/8 of red oak will only move about .005" with an 8% change in moisture content. that is a change in size about the thickness of a sheet of paper. the difference between flat and q/s oak movement is negligible in sizes this small as well. if your glue can't stand wood moving that much you've got some problems to deal with. remember, glue is stronger than wood, and it's gluing two pieces together with the grain perpendicular to each other which causes problems. now in all likelihood the woods moisture content won't ever change that much, so those numbers will be considerably smaller in reality. I just used them to illustrate the point. hope this helps.
Hi Andrew, yes it helps alot! I was thinking (well, pondering may be more accurate) that since the pieces I'm dealing with are pretty small, will be finished, and will be in an indoor environment, that movement shouldn't be a problem, but this display is going to a customer/friend, and I wanted to cover my bases by asking all you experts. Thanks for the info!
Am planning to use good ol' yellow glue, rather than Titebond, for this particular project.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
forest girl,
If you look at some of the beautiful boxes made by the well known Doug Stowe, you'll find further validation of Andrew's comments.
Gerry
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