How to Clean-up Glue Squeeze-Out
How to Clean-up Glue Squeeze-Out
For some reason, this question gets asked quite frequently, so here's my take on the issue.If you're gluing properly, your joints will after clamping, squeeze-out excess adhesive you've applied to the joint prior to assembly. If you don't get any squeeze-out, you're almost certainly starving the joints. The excess glue should form small beads at the joint, and it's worthwhile to pay attention to this and learn from it, adjusting your gluing and clamping techniques with each project until this occurrence becomes normal and predictable.
Old wisdom said that the correct way to deal with squeeze-out was to immediately clean it off the joints with a damp rag. This does work to some degree, and in the case of hide glue, it's still the method I'd recommend -- hide glue sets up extremely hard, and is hell on edge tools -- but if your adhesive of choice is yellow (aliphatic resin) woodworking glue, there is a far better alternative.
Common sense should tell us that it's generally not such a swift idea to wet raw wood. Wood is a natural, organic material, and it reacts often quite frustratingly to being wet. Among the most notable is that wetting wood 'raises the grain' -- wood fibers on the surface lift and create tiny slivers and splinters, which need to be removed before any finishing can be done. There are times when this is actually desirable, but most frequently it's just a nuisance. The other problem with this method is that it's darned near impossible to remove the glue with a damp rag. Basically, one generally ends up removing some of it, and smearing the rest of it around, eventually diluting it sufficiently that it seems to be gone, while it actually may or may not.
With open-pored woods like oak, it will definitely not all be removed, and the pores will become filled with glue, which can result in some hideous looking finishes. After gluing up several thousand feet of wood, I can tell you most emphatically that the easiest and best way of dealing with glue squeeze-out is to begin by being patient. After frantically gluing, assembling, and clamping up a complex piece, the last thing your blood pressure needs is for you to rush around with a damp rag hunting down and killing little beads of glue.
Depending upon prevailing atmospheric conditions, in 20 to 30 minutes the little beads of glue will have skinned over and begun to become somewhat translucent. Locate your broadest bench chisel and simply 'plane' the beads off the joint. They'll come off like butter, and leave the wood surface perfectly clean, smooth, and undamaged.
If you're cleaning a corner joint, such as the corner made by a mortise and tenon joint or a pair of case sides, you can run the chisel along the joint, right in the corner, along both surfaces to slice off the glue. For harder to reach areas, you can approach the joint from the sides -- just push the chisel's edge right into the corner from both directions, and finish by levering the chisel in a scraping action, lifting out the glue. In my opinion, this is by far the best use of a big, wide wood chisel.
The crucial thing is timing, if you start this process and find that the glue is still wet at the joint's surface, just give it another ten minutes and try again. If you absolutely have to wait to clean up squeeze-out later, after the glue is fully cured, I still prefer doing it that way over the damp rag method. It's a little more effort, but with a sharp chisel, the glue still comes off quite easily, since the squeeze-out is just sitting quietly at the surface of the wood, and hasn't been forced into the wood's fibers.