Should I use glue with pocket screws?
To glue, or not to glue, with the pocket screw?
Q:I have a bet with a buddy about glue and pocket-hole joints: He says just drive the screws and be done. I apply glue to the joint for added strength. Which way is right?
—David Roders, Lewiston, Idaho
A:Technically speaking, David, pocket screws possess plenty of strength to hold a joint together without glue. So your joints likely won't fail from using pocket screws alone. But comparative tests show that pocket-hole joints with glue withstand greater forces before failing than joints without. In the case of end-grain-to-edge-grain joints (such as between a rail and stile of a face frame) the added strength may not be huge, but it provides an extra bit of insurance.
Gluing pocket-hole joints prevents the joints from opening or becoming misaligned down the road due to wood movement. Glue resists this movement and anchors the pieces in place, even if the screws relax their grip slightly over time.
But that doesn't mean you win the bet completely, David. In some instances, such as projects that may need to be disassembled later, you should skip the glue. Or you may want to forgo the glue when installing the center stile of a cabinet face frame. This allows you to remove the stile if you ever require unobstructed access to the cabinet interior. But, aside from instances such as these, the few seconds it takes to apply glue provide some extra peace of mind.
Tip! Improve the strength of end-grain glue joints by applying a thin coat of glue to the end grain and letting it sit for a couple of minutes. Then apply more glue and assemble the pieces as usual.
Have a question? Drop us an e-mail.