Choosing the Right Wood Glue
When choosing which glue to use, it is important to do your research. Each type of glue has a perfect use, but we don’t always have that perfect scenario.
Woodworking with Epoxy Glue
When a joint is slightly apart, or, when repairing a piece of furniture, such as a chair that has loose mortise and tenon joints, epoxy works the best.
Epoxy fills the joints and bonds the surface at the same time. It is a two- part glue that combines a catalyst/hardener with a resin/epoxy base. When mixed, depending on the set time of the glue, epoxy leaves a certain amount of time before the glue sets. This can be an asset or a difficulty.
The glue will run with gravity if the joint is not positioned properly or it may set before you have time to put the joint together in the optimum position. Generally there are 2 ton epoxies, which take about an hour to dry and a variety of 5 minute epoxies.
The longer the dry time the stronger the glue joint. All epoxies need about 24 hours to truly set before you take your saw blade or router bits to your piece.
Polyurethane– A Strong Glue for Woodworking
Polyurethane glue is extremely strong and also acts as a gap filler. This type of glue has the unique ability to penetrate into cracks and joints, virtually welding the separate pieces of wood together.
Great care should be taken when preparing a joint for gluing when using this type of glue.
The joint should be dry-fit and as tight as possible where the two pieces come together in order to prevent seepage onto the surface of the work area. If there are gaps, regular masking tape can be used to coat the vulnerable areas for the glue to cascade out onto as it expands… and expand it will!
Another neat trick is to use silly-putty with the same tint as the wood you are gluing. You can apply the silly-putty once the finish has been applied to create a dam for the foaming glue. When the glue has dried, you cut away any excess putty and sand it down to get back to bare wood.
If polyurethane glue does get onto the surface, you can wipe it away with mineral spirits when it is wet and sand after the joint is dry. If the glue dries onto a surface, only cut it away with a sharp chisel and sand it back to bare wood.
Fixing Your Woodwork with Crazy Glue (Cyanoacrylate)
Cyanoacrylate glue, or more commonly known as crazy glue, is used widely for fixing small cracks. It can be used as a gap-filler, but only for small holes and crevices, which when sanded flat can appear as part of the wood grain.
This type of glue works great and is a huge time saver. However, it can also be very messy! Crazy glue will stick your fingers together in seconds and because of its fluidity, it can run out of a hole with gravity before it sets, causing all sorts of trauma to the work-piece and to the woodworker.
The trick to using this type of glue is to use small amounts over small periods of time. This allows you to build the layers as they dry. This method is also cost effective, since this type of glue is fairly pricey. Regardless, crazy glue has a special place in the arsenal of a woodworker’s toolkit.
Woodworking with Glue
In the end, whichever glue you decide to use, planning, preparation, and safety are of paramount importance. Glues are toxic and can cause skin rashes and injuries, so wearing safety glasses and gloves are important.
Remember that wood is a living organism. It needs to breath with the seasons and moisture in the air. When designing a joint, always plan for wood movement, the wider the piece, the more movement.
Glues should never be used to glue wood down to a flat surface, only to bond to other wood. Mechanical fasteners can be used to allow the wood to float, while each piece of wood can be attached together with glue, making one large moving and floating surface.
Always try to make a joint appear as if it grew that way. The best way to use glue when bonding wood together is to use it in a way so when you look at your final wood piece, you’d never know it was glued.
If you have a gap that cannot be avoided, try to match it with the surrounding wood grain in color and grain direction. If you have a hole that needs to be filled, make it look like part of the surface of the wood.
Ultimately, as you practice, every mistake that you make will improve your next project and being happy with your work is the most important thing that you can do to develop as a woodworker, whether you are a professional or hobbyist.
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