Ultimate Guide to Perfect Woodworking Panel Glue-Ups

One of the questions I get most commonly from woodworkers is about gluing boards edge to edge to make wide panels. Makes sense because, if you need big pieces, you don't always want to use manmade materials, and big pieces come into play on dresser tops and, of course, large tables, end tables. So, we're gonna talk about what it takes to build up, to compose a really good panel with edge to edge glue up. One of the things that's really important to understand is that, with today's glues, in many cases, if you have good joinery the glued joint is stronger than the surrounding wood. We have on a number of occasions taken edge to edge glue ups and, for the sake of demonstration, fractured 'em over the edge of a bench, and it never breaks on the glue joint. It always breaks surrounding the joint. So this is a very viable technique, as long as we do it right. So do it right, what are we looking for? Today, I've got cherry boards I'm working with, and we're gonna glue all four of these edge to edge to make up one large panel. What's the first step? The first step, look at the material and figure out what do I need to do to get this to come together so it looks okay? Couple things could come into play there, color of material, grain of material. If you're doing a really large tabletop, I would recommend that you overorder your material by about 10%. You want a couple wild cards to play with here. You want some extra boards so that, as I put things together, if I don't like how they look, I have a lot of options to make changes. When we're doing a project that calls for a tabletop, always do that step first. That's gonna give you the best material, have available the best material, for that top that everybody's always gonna see. Then use whatever's left for the rails and the legs and everything else. So, what am I looking for here? Well, I would like the grain to be a reasonably good match as I'm putting parts together. So it doesn't make sense to do a super wild grain pattern against a really straight grain pattern 'cause it'll be really obvious that I have a seam there. I want the grain to be similar. Color match? If possible, on a small glue up like this, if you can get all the boards required for the glue up from one board, that's pretty good guarantee of getting color match and grain match. So that's a great approach to take. So first step, let's get this figured out and see what I'm looking for. I'm gonna put that wilder grain, I think, to the outside. And of course, we can turn end for end. Now while I'm doing this, while I'm looking at these parts, let me talk about, people ask about, "Well, what about the end grain? "Should I be alternating the annual rings as I do this?" I don't do that. I do not alternate the annual rings. My experience with this is that, as long as our material is stable, meaning it's kiln dried, it's had the opportunity to acclimate to your shop, you can have the annual rings in any configuration you want, and your tabletop is gonna be just fine. It's gonna stay flat. Again, it depends on the material being already stable. Once I see how I want the table to go together, then the next thing is to label the seams. So this is gonna become number one, two, three, and the big deal with this is that, especially if I'm working with a lot of boards, when we get to the gluing and clamping step, which is next, we don't want to be fumbling around with these trying to remember what goes where. We want to have a roadmap that indicates exactly where we want the boards to go. Gonna throw down some paper so I don't get glue on my workbench. Let's talk about clamps and number of clamps 'cause that has an effect on what we're doing. When you put clamp pressure on, the thing to keep in mind is that pressure comes off of our clamp heads in about a 45-degree cone. So what that means is that, here's my clamp head, imagine a 45-degree cone of clamp pressure, and what I want is for the cone coming off of the adjacent clamp to overlap the first one. So on this glue up, it's looking to me like three clamps. Two clamps maybe could do it. Three clamps are gonna be great because that's gonna give me nice overlapping pressure all the way down, good uniform pressure throughout the glue up. Another question I get all the time doing a glue up like this. "Do I need to add biscuits to the joint "or some other kinds of reinforcement, dowels, dominoes?" And the answer is no. It goes back to that idea that the glue we're using, once we have good joinery, is stronger than the surrounding wood. Now, if you want to add biscuits, dowels, dominoes, for the purpose of registering the faces, that's not a bad idea. And what I mean by that is that, as we glue this up, we'd like to keep this top face aligned so that we don't have to do lots and lots of flattening later. That's something the biscuits or dominoes or dowels will do for ya. But as far as the structural integrity of the joint, it's not required, provided we have good joinery. Good joinery, what am I talking about? I've already taken these boards to the jointer, and my test, when they come off the jointer, is to hold 'em edge to edge, and if I can, if they're small enough for me to handle it, I want to hold 'em up to a light and see if there are any spots down the length of that joint where light comes through. If we can close the joint with hand pressure, imagine what a great joint that's gonna be once we have glue and clamps. Excessive glue and excessive clamp pressure will not overcome lousy joinery. So if you're doing this and you see a gap, and in your head, you say, well, that's okay, my big, beefy clamps are gonna pull that closed, that's not what we want. That joint will eventually fail. We should be able to hold these together with hand pressure, not see any gaps. Then you know that you have great quality joints. I'll tell ya a story while I'm applying glue here. When I taught overseas, taught for Peace Corps in Africa, we didn't have enough clamps to go around. So, pretty commonly the kids would hand plane edges and then do what's called a rub joint, glue on one surface, literally rub the boards together like that and let 'em stand vertical like that overnight. Plenty strong. The reason being, the rub joint actually creates a little vacuum in there. That's what holds the boards together. Because the edges were nice and straight and a true edge, the glue had the opportunity to do what it needed to do and create a very strong joint. Next question, one edge or two? I always glue one edge out of each pair, but the key to this will be making sure we have enough glue on it, and I'll show ya what I'm looking for in enough glue. Analogy I use is think of it as though you're painting a wall. When our painting is done, when our gluing is done, we want a surface, see how opaque this is right here? I can't see or can barely see the wood grain through it. That's the volume of glue I want to have on my edges. If we do that to one edge, I find, you're gonna be just fine for volume of glue in this joint. Now on this end, I'm gonna say I'm a little dry here. It's not quite as opaque as I would like it to be. You can't apply too much glue really, except that it creates such a huge mess, oops, as it starts to come out of the joint and drip all over your project or your bench. Now, as we're getting to this step, this is where having the lines on our boards really pays off 'cause we don't have to fuss and fidget with our boards. We can tell by the registration lines exactly where everything is supposed to go. Next step, I get the ends approximately aligned. However, you shouldn't have to worry about that too much 'cause what you should be doing here is gluing up a panel that's larger than what you need when you're done. If there's a center clamp, I kind of like to do that clamp first for tightening, and as I give it a little bit of pressure, I'm feeling across the joint to make sure they're level. Those feel pretty good. Then go one clamp over. Gentle pressure. One clamp in the other direction. Check your registration. Gentle pressure. How tight do the clamps need to be? Not too. As soon as you see glue start squeezing out of that joint, you're probably done with the clamp. Remember that story I told about the kids in Africa hand planing and then just using a rub joint? It does not take a lot of pressure, and in fact, if you overdo it with the clamps, depending on the type of clamp you're using, you can get too much pressure on there and bow this panel. And that's also gonna mess up your glue joints 'cause you're starting to cock the boards relative to each other. So just enough pressure to keep that joint closed. That's gonna be fine. What about the squeeze out? Great question. What I do with this is I allow it to get to a stage where it's a little bit rubbery, kind of like caulk, and then I slice it off the surface with a sharp putty knife or a glue-specific chisel. It's not my good joinery chisels. It's kind of a crummy old chisel I sharpen on a belt sander just for cleaning the glue off. Once the glue is dry, you're gonna have a beautifully composed panel here that'll also be strong, flat, look great. This is the way to make sure that, in your woodworking, you're composing good panels that are structurally sound, look good, have good joinery.