You can’t hammer or screw wood together; you need to use a bit of glue. Gluing wood creates more secure bonds. It minimizes the damage caused by vibrations, which can loosen nail or screws as well as conform to expansion or similar size change in wood.
Carpenter’s Glue (Polyvinyl Acetate or PVA Glue)
Your first encounter with glue probably involves PVA glue. It is commonly used in crafts and hobbies (Elmer’s Glue), but hardier varieties can be used in wood projects. PVA glue is non-toxic and easy to clean. It sets permanently once cured, and you might need to shave off the glued part and reapply glue if ever you need to make repairs. There are several variations of PVA glue. Some are designed for outdoor use and are water-resistant while the more basic variations are just suitable for small projects.
Unlike most glues, epoxy requires a two-step process to bond wood. Epoxy comes in two containers, and you have to combine the resin and hardener before you fix the wooden parts. It can be used as a filler to make up for damaged wood. Epoxy is water-resistant and won’t degrade when exposed to UV or heat. Be careful when mixing the resins as the fumes can be overpowering, especially in confined spaces.
Super Glue (Cyanoacrylate or CA glue)
CA glue is mostly used for small repairs involving smaller pieces of glue. It dries quickly, relying on the moisture in the air to create strong but brittle bonds. CA glue has a very short shelf life and can be made inert by exposure to moisture.
Gorilla Glue (Polyurethane Glue)
Polyurethane glue also relies on moisture to cure, but it requires more than just what’s in the air. You’ll need to moisten the wooden parts you want to connect before applying the glue. It expands as it cures so make sure you hammer or clamp the pieces tightly and leave no gaps. You can also use polyurethane glue to bond wood with metal, plastic, and other materials. Polyurethane glue creates strong bonds and is waterproof.
Hot glue requires a “glue gun” to use. The heated glue is then dispensed through the gun and applied to the wood. The glue is sensitive to heat and can be removed just by reheating. It sets quickly, but it doesn’t hold wood together as well as other glues. One way to use hot glue is to use it in conjunction with a slower-setting glue. Apply wood glue normally, but leave space for hot glue at the center. The hot glue sets faster, acting like a clamp that holds the wood as your primary wood glue slowly sets.
Like hot glue, hide glue requires heat for it to be applied. It often comes in granules that need to be melted and used before it cools. It isn’t as strong as most glues (perhaps at par with PVA glues), and it isn’t waterproof, but it is reversible. Merely applying a bit of heat removes the glue, making it ideal for antique pieces.
You can find most of these glues for sale on your local hardware, or you can buy them online if you don’t have time to leave the house. Just take time to make sure that you’re using the right kind of glue for your particular project.