5 Wood Gluing Techniques: How to Use Wood Glue Effectively for Your Projects
Does using wood glue for your projects intimidate you? Follow these wood gluing techniques to make gluing wood together easier.
Wood is a great material to work with as most wood species are easy to glue. Wood is porous and glue can grab onto it.
In fact in some strength tests, the glue held and it was the wood fibres that broke and caused the joint to fail.
However beginners usually find using wood glue to be stressful and difficult. Glue sets up quickly and if you are not prepared, will dry before you have a chance to put the two pieces of wood together.
Clamping also seems to be a worry – do I have enough clamps?
And having glue squeezing out everywhere is messy and can make you lose it as you try and clean up before the glue dries.
Let’s look at five wood gluing tips, so that you can actually enjoy gluing wood together.
Best Glue for Wood
There are many glues on the market. And then there is a subset of all the glues especially for woodworkers. So many that it’s hard to know what glue to use.
For the beginner I suggest keeping it simple.
Wood glue is readily available, easy to work with and cleans up with water while wet. There are different formulations depending on where the glue is used and how much working time you need.
Titebond III is the most popular with most woodworkers and is food safe, important if you are gluing up wood for a bowl turning or a cutting board. Or if building toys and furniture for your kids. It also has a longer working-time glue so that you don’t have to rush gluing wood together.
The other recommendation is to also have a bottle of gel-type cyanoacrylate adhesive (CA) glue (more commonly known as super glue or crazy glue) on hand. This comes in handy for trickier glue joints which you might not be able to clamp easily. You can add a few dabs of CA between the wood glue to have it temporarily grab until the wood glue has a chance to set.
Having a CA accelerator is also handy, where you put CA glue on one piece, spray the accelerator on the other piece and then join them together for an instant bond.
A good idea if you start using it a lot is a kit with the three viscosities of CA glue and the accelerator. Just keep in mind the shelf life of CA glue can be short if you don’t ensure the bottles are firmly closed each time you use them.
Use enough glue
The mistake most beginners make is not using enough glue and not distributing it evenly. Then what you end up with is what is called a starved joint.
With not enough glue, you have voids and places where the wood simply doesn’t bond together.
You basically want a thick enough coat of glue so that when you apply clamping pressure, you get a bead of glue squeezing out consistently along the length of the glue-up.
The best way to find out how much is too much or too little is to experiment. Grab two pieces of scrap wood, apply glue to both surfaces and clamp it up. Check to see what kind of glue bead you get.
Too much glue will mean that you get huge drips of glue.
Too little means you won’t see that consistent bead.
Apply glue also requires using the right tools. In a pinch you can use your finger to spread the glue, but I wouldn’t recommend getting used to doing that. When you move to other glues you might be tempted to do the same but with stickier results.
The cheapest and most readily available tool is still an old toothbrush! With it you can easily spread the glue.
Other alternatives if you want to spend some money are rollers and special silicone glue brushes that you can easily clean dried glue from. Special bottles with different attachments make certain glues easier but keep in mind that these need to be cleaned each time you use them.
Use enough clamps
Clamps are the woodworker’s best friend. The saying goes that you can never have enough clamps.
Clamps apply pressure to a glue joint so that the entire joint pulls together and the glue can bond to both pieces of wood.
Clamps generally can’t fix a badly prepared joint. So you do need to make sure that the wood is straight and the joint closes tightly by itself without clamps.
There are so many types of clamps. For the beginner I would recommend using quick adjustable clamps. They come in various lengths.
For larger projects you should get some bar clamps or pipe clamps.
When clamping up, remember to use some scrap wood to protect your project from the clamp ends.
Use other forms of fasteners for butt joints
Butt joints are when you literally butt up two pieces of wood, usually at a right angle to each other.
This is the weakest joint and for small projects that don’t see much handling, you may be fine with just glue.
But for projects where the glue joint will be under stress or where you have glued end grain, you’ll find the joint will be very weak.
So in addition to the glue, you need to use some other type of fastener.
These are cheap and are really designed to hold the joint together while the glue dries. Typically nails don’t have much holding power for pulling forces. They mainly keep joints from moving laterally apart.
They can be set into the wood and then filled with a suitable wood filler to effectively hide them.
These are a step up from nails and the advantage is that they resist pulling forces quite well. It’s important to pre-drill and use screws of the correct length.
These are harder to hide. Often plugs are used, either matching the grain and colour of the wood in order to hide them or in a contrasting wood to emphasize the plugs.
Dowels, pegs, dominoes and biscuits
These are all types of hidden fasteners. Getting alignment right is difficult unless you use the right tools. Dominoes and biscuits are best installed using dedicated power tools that are expensive so not the best for the first time woodworker.
There are two types of splines. Ones that sit inside the joint, mostly hidden from view and those that are on the outside of the joint and considered decorative as well as reinforcement.
Often used on mitred joints as these involve end grain to end grain glue joints that are inherently weak. A slit is cut into the joint and then a thin slice of wood is glued into the slit. Using a dark wood for the spline with a lighter main project wood or vice versa adds a decorative element to your project.
Clean up excess glue
With the recommendation to apply enough glue so that you get a consistent bead of glue all along the joint, you’ll now have to clean that up.
Not only does the glue bead look messy but it’ll also inhibit your finish from penetrating the wood.
To avoid the mess altogether, you could apply painter’s masking tape to both sides of the joint. Once you have done the glue-up and while the glue is still wet, you can remove the tape and have a relatively clean joint.
Or after you’ve tightened the clamps, you can wipe off the excess glue with a damp cloth. There’s a danger with doing so though as the diluted glue could sink into the wood, permanently sealing it against the finish you’ll be applying.
A better method is to wait until the glue “skins over” and then use a scraper, chisel or even a thin piece of wood to scrape off the glue bead.
Some woodworker prefer to simply wait until the glue is completely dry and then use a plane or hand scraper to scrape off the glue. This works but can result in tearing off wood fibres along with the glue.
Or if you are doing a panel glue-up and have access to a jointer and planer, you can use these power tools to clean up the excess glue and at the same time flatten the panel. However this can gum up jointer and planer blades and can dull the blades over time.
Gluing wood together can be intimidating at first but with a bit of practice and these wood gluing tips, it should become easier over time and less stressful.
As mentioned in the Getting Started in Woodworking article, start with simple projects that don’t require complicated glue-ups.