There is a boat load of great wood glue in the market place, and this can be confusing. This story will help you narrow your arsenal down to four must-have types of glue, and tell you why you need them, and where you’ll use them. Here are the four go-to glues in my shop.
Yellow Glue. This is the stuff we’re all the most familiar with. Yellow glue, carpenter’s glue… the old stand by. If you want to know the chemistry, yellow glue is an aliphatic resin in the polyvinyl acetate family.
If you’re building furniture and cabinets yellow glue will handle almost all of your gluing needs. It’s easy to work with, can be cleaned up with water while it’s wet and, once cured, is stronger than the wood you’re gluing together.
Yellow glue sands better than its cousin, white glue, which has a tendency to get soft during sanding and gum up your paper. Standard yellow glue isn’t water resistant, so it’s not a good choice for damp applications. One down side… yellow glue tacks fairly quickly so you’ve got to keep moving while gluing up so the parts don’t start to grab before you’re ready.
Titebond III. This is not a type of glue, it’s a specific brand. Titebond III is water resistant, and has most of the working characteristics of yellow glue. Its sandability is good, and it has about a 10 minute open time. Although water resistant when dry, it cleans up with water when wet. Titebond III is not a glue you can build a boat with, but it’s an excellent choice for cutting boards, outdoor furniture, and other items that will see moisture. The only reason to not simply substitute this product for yellow glue across the board is price, Titebond III being more expensive than yellow glues. The presence of moisture in the material being glued will retard the cure time of Titebond III.
Polyurethane Glue. Polyurethane glue is another water resistant adhesive. Polyurethane glue cures in the presence of moisture, so the material being glued has to be damp for this glue to work. That characteristic makes this product a great choice when assembling projects made from pressure treated wood, which is often damp. If you use polyurethane on kiln dried stock you’ll have to spritz a little water on the joint in order for the glue to work.
End grain to end grain joints are historically problematic when it comes to strength. Polyurethane glue is a good choice for this application, doing a better job than yellow glue of handling porous end grain.
Polyurethane glue is a good choice for gluing non-wood items. It’s slightly more gap-filling than other glues, but don’t count on it to take the place of good joinery. It foams as it cures, making a big bubbly mess at the joint. DON’T WIPE THE BIG BUBBLY MESS! Let it get hard, then cut it off using a sharp chisel.
Ambient humidity can be enough to make this glue cure. So, once you’ve opened the bottle, you need to use it up fairly quickly.
Cyanoacrylate. CA glue (cyanoacrylate) is the super glue of the wood shop. There are so many places I use this stuff. It bonds quickly. In fact, nearly instantly. It’s available in different viscosities, from watery thin to jelly thick. The thin stuff can be flowed into punky wood to reinforce it, saving a piece you might have otherwise thrown out. The thicker stuff will fill gaps. I use CA glue in my woodturnings all the time, and it has saved a number of bowls (where I caught a chisel and broke the rim) from the fireplace.
Downside? CA glue is brittle. It certainly wouldn’t be a good choice for a mortise and tenon joint, or any place where daily stress could crack the glue. Relative to other glues, it’s expensive. The fumes from this glue can be irritating, and some people react adversely to them, so be careful there.
CA glues can be used with or without an accelerator. The accelerator speeds up the cure process, changing a 30-50 second cure time to a right now cure time. If you use accelerator put it on one surface first, since it has a longer open time than the glue. Put glue on the mating surface. Once you touch the two together, you’re done. Be conservative with the accelerator. Sometimes using too much can weaken the joint.