Session 1: Strength of Glue Joints

When you do your woodworking projects, I know that you really carefully pick the material you're going to use, you buy hardware that you pay a lot of attention to, you get to the finishing step, you pay a lot of attention to detail there. And somewhere in that mix of stuff, you need to be carefully thinking about glues, about adhesives, because there is a huge array of adhesives in the marketplace. And that's what we're going to be all about here. It's not as simple as just grabbing a bottle of glue off the shelf and , because glues have different applications, they have different gap filling capabilities. Some like to have moisture present to dry, some will never dry if there's moisture present. There's a lot of chemistry going on here. So what we want to do is cover the bases, and make sure you get all the information needed to make good decisions. Why is this board laying here? Well, this is a board I already glued up. And one of the things I talk and talk and talk and talk about is the strength of glue, the strength of adhesives. And the bottom line is that across the board, all the glues we're going to talk about, they are stronger than whatever it is that you're putting together. In this case, what I've got is a red oak glue up, two pieces. I left the glue beads on there because that shows you where the sheen is. I jointed each of those edges, we glued this together. What we're going to do is fracture this. That's why this vice is sitting here. And here's my prediction. When I do this, this is going to blow apart somewhere on either side of that glue scene. Let's see if I'm right or not. Gonna aim for the corner of the vice, shooting for the center of the board. So I want to hit as close to that glue joint as I can. It's going to be noisy. Here's what we've got. Busted edge, busted edge, there's the glue scene. I find that pretty incredible. Now, this is all predicated on a couple of things. The joinery was sound, so that we had good wood-to-wood contact. The right glue was chosen. Now we did a bigger scale experiment than this, where we took a cabinet that was completely put together, plywood carcass, solid wood face frame, and fractured that cabinet. And the results were amazing. Without a bunch of mechanical fasteners holding stuff together, when that thing came apart, it was... The face frame was pulling the plywood with it. The rail was pulling edges of the style with it. Another great example of the way glue can very, very successfully hold stuff together. So we're going to talk lots of different glues. There is a handout that comes with the class and all that information, all that data is there as well. So you don't have to take notes as we go. Just look at the handout as we go and that'll give you the specs on the glue and then also help you nail down what glue is the right glue for your project. Let's get started edumacating you about adhesives.