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Don’t Get Stuck with the Wrong Glue

December 12, 2018Sharewoodworking

While there are many glues you could use when working with wood, the wrong choice could ruin your project in any challenging situation. We’ll discuss the right type of glue for some of the most common projects and situations you may be in. We’ll also share a few tips for working with both wood and glue.

Epoxy Glue

Epoxy glue is the best choice when you’re trying to repair a piece of furniture or a joint that’s coming apart. Epoxy glue isn’t right for sticking a table on a leg, but you can use it in loose mortise and tenon joints of a chair. It will both fill in the gap and hold both sides together.
Epoxy glue is made by mixing a resin or epoxy base and a catalyst or hardener. Depending on the brand, you’ll have a certain time to wait before you apply it, and then you need to wait the necessary time before it is set. One of the downsides of epoxy is that it will run while it sets. If you don’t hold the item in the best position while the epoxy sets, then things are even worse. The longer the glue has to dry, the stronger the joint. Try to cut or grind the joint before the glue has set for 24 hours, and you could affect the so-called repair joint.

Polyurethane

Polyurethane is both a strong adhesive and gap filler. It is a better material for filling in the fine cracks in a damaged piece. However, this can work against you, too. You must be careful to prepare the joint before you apply polyurethane glue. The area needs to be dry-fit, and the fit should be as tight as possible. When you apply the glue, it will have a tendency to seep out and fill every little crack.
You can protect areas where you don’t want glue to reach like engraved areas with masking tape. Another option is creating a “dam” with silly putty. The downside of this approach is that the silly putty itself will adhere, in part, to the wood. You’ll need to cut away the putty and sand off any remaining putty, but this is easier to do than with the glue.
It is possible to try to remove polyurethane glue without sanding down the area you just repaired. If the glue is still wet, apply mineral spirits to cloth and then wipe it away. If the glue dries, you can try to remove it with a sharp chisel.

Crazy Glue

Crazy Glue is the brand name for the biggest seller of cyanoacrylate. This glue is regularly used for fixing small cracks. Interestingly, you can use it to close up small wounds, too. It’s been used for that purpose since at least 2001.
One benefit of cyanoacrylate is that it is essentially clear. Use it to fill in small gaps, cracks and holes. It will quickly fill in and blend in with the wood grain, once you’ve sanded down anything that rises above the surface. However, the fact that it can work as a medical suture works against you, since it will stick to your skin in matter of seconds and be hard to get off. Another issue with cyanoacrylate is how liquid it is before it sets. The same fluidity that causes it to fill every nook and cranny causes it to flow through little cracks in the wood or get all over your hands. You need to take care so that it doesn’t flow out of holes and joints before it sets. Silly putty dams can be used for that purpose. Wear gloves when working with Crazy Glue if you want to avoid the hassle of scrubbing it off.
The best way to use Crazy Glue is to apply it in small amounts, allowing it to dry, and then lay another layer. This prevents it from overflowing, and you’re less likely to spill it while working with it.

General Tips for Woodworkers Working with Glue

Regardless of which type of glue you choose to use, there are a number of safety tips and tricks you need to know. First, glues are often toxic. Wear gloves to keep it off your hands. Wear safety glasses so it cannot get into your eyes. If you are applying a lot of glue or grinding glue-covered surfaces, wear a face mask to avoid inhaling the fumes.
When you’re designing wood, remember that it needs to breathe and will expand when exposed to moisture. Allow for wood movement in your furniture designs. The wider the piece, the more movement it needs to be allowed. Don’t use glue to fight this, or the stresses will result in damage elsewhere in the wood.
Try to make joints appear natural. If you have to glue something together, make sure no one can see that it was glued together. Don’t glue wood down to a flat surface; mechanical fasteners are better for that job.
If the wood has a hole that should be filled, try to make it blend in with the wood. When there is a gap you cannot fill, match it to the wood grain’s direction and color so that it blends in.

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