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Stainable Glue

If you've ever carefully applied PVA glue to a vertical surface, as when attaching trim to a case, only to watch it run down the side and make a mess, you might want to give molding glue a try. Molding and trim glue is specially formulated to stay right where it's applied, until you want it to spread out. A look at the photo below gives you the idea.

The fancy term for the property at work here is thixotropy. What this means is that when the glue is "at rest," it's thick and gummy. But as soon as it gets stirred up, as when two pieces are pressed together, it becomes fluid and spreads out just like standard PVA glue. The result is a snug-fitting joint, without the extra aggravation and time spent cleaning up.

Dark PVA Glue

You know that wood comes in lots of different colors. But until recently, PVA glue was only available in white or yellow. But now you have another option.

Dark wood glue, as you might guess, is meant for use with dark-colored woods such as walnut or mahogany, or even when a dark stain is going to be applied to a project. As you can see in the photo below, the medium-brown color of the dark glue is a little closer match to the color of the walnut board.

When I do a glueup, I try to make sure the glue is limited to the inside of the joint and doesn't show on the surface. But if you want a little insurance against light-colored glue showing up against dark wood, this new glue might be the answer.

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You complete building a project, carefully sand your hard work and then begin applying the stain. Only then does the glue left in a corner or along a joint line come to light. The stain won't penetrate and the spot sticks out like a sore thumb.

Stainable PVA glue is an attempt to hide this common problem. The trick here is that the glue has wood fibers mixed in with it. The wood fibers absorb some stain, so you're actually staining the glue, not the wood beneath it. As you can see at right, the wood fibers make the stainable glue (lower) darker to begin with. And then it does stain a little darker yet. But honestly, I wouldn't rely on stainable glue as a cure for sloppy cleanup.

► Wood in the Glue? When you apply this glue, you'll notice that it looks a little "gritty" due to the wood fibers that are mixed in.

Fluorescent Glue

When you mention fluorescent PVA glue to a woodworker, the most common reaction is a blank look. But after thinking about it for a minute, the idea behind it clicks.

Fluorescent PVA glue has a harmless dye added to the mix that causes it to "glow" when exposed to ultraviolet (black) light, as you see in the photo below. Other than this unique feature, it's just standard PVA glue.

The problem this "glow-in-the-dark" glue aims to solve is a common one — finding all the squee-zout and stray spots of glue that may go unnoticed during or after the assembly of a project. You just turn the lights down, pass a UV light (mine is battery-powered) over the project and even "invisible" spots of glue will show up. A

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