Old cabinetmaker told me to glue miters with just glue and no biscuits. Total failure or valid method?

A retired guy named Dave at a lumberyard in Nashville swore that biscuits weaken miter joints. Tried it on a set of crown molding last week and three joints popped open in the heat. Who sticks with just glue and who uses biscuits?

2 comments

2 Comments

rivera.simon19d agoMost Upvoted

DUDE. The old guy was DEAD wrong. I tried glue-only miters once and they popped like bubble wrap in the summer. Biscuits keep things from slipping and add some real strength. You gotta use them, especially with crown molding in the heat. Just glue is asking for a headache.

davidwright19d ago

I feel your pain, but I gotta say that cabinetmaker had a point. I once glued up a mitered picture frame with just glue and thought I was being slick, then I sneezed and the thing splintered into three pieces. Biscuits are not magic but they keep the joint from sliding around when you clamp it, and that's half the battle. For crown molding in the heat, I'd say you need both glue and biscuits plus some splines or a reinforced corner block if you want it to hold. That old guy might have been right about biscuits weakening the glue line if they're too thin, but I'd rather have a little mechanical grip than a clean pop. Next time try a polyurethane glue on top of the biscuits, it foams into the gaps and laughs at temperature changes.