End Grain to End Grain Gluing
In principle, gluing end grain results in a very weak joint. But in a pinch, there are ways to improve the bond. October 2, 2007
I'm looking for tips on gluing end grain. We don't often have to do it, but when you have to, you have to. Using yellow glues like TBII, are there any special procedures to use for getting stronger glue joints there? Sanding?
From Professor Gene Wengert, Sawing and Drying Forum technical advisor:
Gluing end grain without some sort of special joint (such as a spline) is next to impossible. It is like trying to glue the end of a bundle of soda straws to the end of another bundle. Contact area is quite limited.
From contributor B:
Poly glue (with a wetted surface) is supposed to work and also Titebond III, but the bond won't quite be up to the strength of a long grain to long grain joint. Epoxy is also usable and with greater adhesion. What is the joint on and how much adhesion is needed?
From contributor G:
I have a wood engineering degree and my response to this question has been for some time the same as the doc's... but I really believe it's all relative. Popular Woodworking recently had an article where they tested the strength of many types of joints. All of the miter joints actually ended up with mostly wood failure (good) instead of glue failure (bad). All in all, it's usually best to find a way to reinforce it, but if the strength demands placed upon it are not great, you may be able to get away with it.
From the original questioner:
Thanks all. There is no particular application I have in mind. I was just looking to educate myself on this one. I had a paint-grade cabinet the other day I was making and mis-cut one of the poplar stiles too short, and I didn't have any more poplar laying around long enough. I butt-joint glued another piece to it to make it long enough since I had no other choice (other than just not get that cabinet primed in time). I did make sure the butt-joined pieces were well attached to the carcass as I would have individual pieces (nail gun), so it's not coming off. Thanks for the help. Next time I'll likely dowel it (or just cut it right the first stinking time.)
From contributor P:
Next time you glue a butt joint to "stretch" a board, miter both ends 45 degrees first and use a cynoacrylate glue. If one side won't show, you can drill and glue some dowels in from the back side after the glue is set. It's a cheap trick, but I've been there and done that too.