How to Clean Glue Squeeze-Out
George VondriskaDescription
If you’re putting woodworking projects together, you’re going to get squeeze-out. It’s nearly impossible to avoid, but it can actually be beneficial. A little glue coming out of the joint provides some reassurance that you have enough glue IN the joint. The question is, what do you do with squeeze-out?
It depends…
How you deal with glue squeeze-out depends on the end use of the project. One thing George avoids, at least most of the time, is wiping the glue with a damp rag. He’ll explain why he thinks this is a bad idea, in most cases.
Exceptions to the rule
There are, of course, no hard and fast rules in woodworking. This means that there are times when using a damp rag is OK, and you can get away with it. It has to do with what the next step is. How you’re following up the gluing operation affects how you deal with the squeeze-out.
There are many approaches…
George explains what you shouldn’t do with squeeze-out, and gives you some tricks for dealing with it, but there are a number of approaches to this problem. Check out our great article that covers tips for cleaning glue squeeze-out. And, while you’ll nearly always have squeeze-out on your projects, there are ways to prevent it from ending up being a huge mess. Inside corners are notoriously difficult to clean glue out of, but there are ways of protecting inside corners from glue squeeze-out.
All right, so let's do a little myth busting, at least myth busting according to me. This whole question of wiping glue squeeze out with a wet rag. I almost never do it. 99% of squeeze out in my shop does not get wiped with a rag dipped in water. And here's the reason.
So yellow glue is water-soluble. Great news. If this is wet, and I start working on these seams to try to clean that up, a couple things are going to happen. This is red oak. Water raises the grain like crazy on red oak.
So generally on a big panel like this, I've pretty well prepared these boards coming to this point. They're flat. They're reasonably smooth. They're in pretty good shape. If I raise the grain, I'm going to have to knock that back down.
But even more critical, you know, knocking the grain back down, that's a sanding operation. I can make that happen. But I think what's worser is when this is wet and I start wiping that glue, what I'm really doing is I'm smearing it all over the place. Now, the theory is, the wet rag is removing the glue residue. However, if I don't get it all off and I'm leaving a film of glue in the wood, when is that going to show up?
When I get the first coat of finish on here. So right now what I've got are glue beads that are really isolated. They're right on the seams. And what I'm going to do with these is, when this gets a little bit rubbery, maybe 15 or 20 minutes after I put it on, I'm going to take a putty knife or a chisel and I'm going to slice that glue bead right off of there. It's going to clean up really well.
If I start moving it around with a wet rag, I'm going to have a problem. So for me, maybe you do something different that works for you, I never wipe with a wet rag, and that's why. Now the reason the end grain cutting board is laying here is I did say 99% of the time I don't wipe with a wet rag. End grain cutting boards are an exception. Now, the way these get glued up is you stand all these strips up.
You glue them together. It's quite an uneven surface. There's glue all over the place. I know that the next operation following that glue up is going to be lots and lots and lots of leveling to get this flat. So, because I know I'm going to take off, geez, at least a 16th of an inch worth of wood in order to get this flat, that tells me, if I wipe this with a wet rag and I leave glue residue on the surface, when I do this leveling operation, I'm going to cut that glue residue right off of there.
So my qualifier to this whole thing is, if this panel is getting glued up and you've got a planer that wide, and you're fixing to send this through the planer to level the whole thing out after the glue up, go ahead and wipe the glue. If you don't have a planer or a surface sander to handle that and your next step is a random orbit sander, don't wipe the glue. Cause I think you're still gonna have residue. So that's my approach to it. Like I said, you know, different recipes for different woodworkers.
But for me, most of the time I let that glue sit until it's rubbery. Then I slice it off. The exception being when I know there's going to be a pretty aggressive machining operation following the glue up, then you can get away with wiping it. So pick the approach that works for you and your shop and go from there. But whatever you do, don't leave glue residue on that project.
How do you deal with through tenons? Do you place glue on the tenon and/or the mortice? If you put the glue in the mortice, the mortice will collect the glue as it passes through. If you do not place the glue in the mortice, the bond between the mortice and tenon will be compromised to some degree. And then there's the issue of glue collecting on the tenon as it's pushed further in the mortice ready to squeeze out onto the cheeks as the tenon is fully slid into the mortice. So what do you do?