Wood Gluing Tips for Achieving a Better Glue Joint

Wood and glue have been coming together for centuries – a dynamic duo, bonding to one another to create the best of form and function. Modern wood glues produce long-lasting joints and, despite the availability of newer joinery methods utilizing metal fasteners or other such accessories, wood glue remains among the most preferred methods of wood joinery. After drying, the properties in wood glue result in a secure, enduring bond that allows woodworkers to produce remarkably durable joints using only a small slathering a glue.

When glue-only joints are properly executed, the joint can be equally strong, or more so, than a solid piece of wood. Of course, the operative word there is properly. Although creating good glue joints is relatively simple, there is still better way to craft them. Here are a few techniques you should employ to ensure your glue-ups are as tight, secure and smooth as possible.

Best Practices for the Most Successful Glue Joints

When gluing sections of wood together, the process can be broken down into three basic parts. The gluing part, the assembly part, and the clean-up. Remaining conscientious throughout each step will ensure you can efficiently create the strongest, most attractive bond.

Part 1: Gluing

Use the Right Glue

There are a handful of good glues out there that will offer you better results depending upon the type of project your building. While yellow glue, the most conventional woodworker’s glue, is ideal for nearly every type build, you may want to opt for something extra – for example, a waterproof glue or one that gives you more time before setting. Get to know your glues and epoxies and have a few on-hand to ensure you have the right glue when met with any given circumstance.

Mask Glue Joints Before Finishing

If you choose to prefinish your materials before glue-up, mask your glue joints first. Though glue bonds powerfully to raw wood, it will not stick well to stains or varnishes. To achieve the strongest joints, then, keep the glue points free of finish. Simply mask off the areas you need to glue (preferably with a no-bleed tape that will resist liquid finishes), and reveal the raw wood only when your ready to glue.

Spread Glue Completely Over Large Surfaces

When gluing together large surfaces, it’s important to ensure the full surface is coated with glue. If spaces are left un-coated, the result is a joint with gaps, and gaps, of course, result in a weak bond and a compromised joint. To ensure a fully coated surface, spread the glue as such: after drizzling glue over your material (you know, in those fancy squiggles and spirals), use a notched trowel to spread the glue evenly over the entire surface. Simply rake the trowel over the material until the joint is entirely coated. Of course, you should add glue as necessary to achieve a full spread. Don’t rely on the glue to spread itself; while it will squeeze around to a point, your joint will only be as strong as your glue coverage.

In Tough Areas, Apply Glue with a Flux Brush

When applying glue to areas that are more difficult to reach, use a flux brush to spread glue thoroughly over the joint. This is a much better method than trying to drip glue where you need it. Just dip your brush into the glue and spread. By keeping the bristles submerged in water, you can keep any excess glue from hardening and reuse the brush.

Part 2: Assembly

Keep Your Clamps Glue-Free

Before you set a glue-up, take precautions to ensure your clamps (and your work bench) don’t get sullied with excess glue. The moisture in glue is bad for the clamps and, when coupled especially with steel clamps, that moisture can leave dark stains on your material, too. To avoid this, cover your clamps with a water repellent material, like wax paper, to ensure drips get caught and can be efficiently disposed of. This step is especially crucial when using bar clamps which often endure a showering of excess glue drips as your joint dries. Make set-up and clean-up simpler by catching that glue before it makes a mess.

Gluing Small or Intricate Pieces

Clamps are a life-saver – woodworkers rely on them heavily as an integral part of the woodworking process. Sometimes, however, clamps can be nearly impossible to situate. When your glue joint is very small or intricate, try skipping the clamps altogether and opt for a gel CA glue (super glue) instead. This will bond your pieces together quickly and tightly without requiring clamps.

Glue Only One Joint at a Time

Like most things, glue is slippery when wet. Often, when gluing multiple boards to create a larger panel, it can be painfully difficult to perfectly align adjoining surfaces. You can avoid this obstacle by simply taking it one board at a time. Allow the bond to set for around a half-hour, and add another board. This allows you to ensure your surfaces are smoother, that you’ll spend less time fighting boards that are dying to slip out of alignment, and you’ll spend less time sanding later, too.

Part 3: Clean-Up

When working with glue, invariably you’ll encounter some amount of mess to clean-up. Many crafters disagree about the best way to manage this clean-up, but hopefully these ideas will help you come to your own best conclusions.

Using the right amount of glue is a key factor in achieving a strong joint and in minimizing your required clean-up. While finding the magic amount of glue takes some practice, the perfect glue joint will always result in a thin line of glue beads outside the entire length of the joint. Of course, this glue then needs to be wiped, scraped or otherwise cleared away. This is where the debate lies – is it better to wipe away wet glue, or scrape away dried glue? The best answer might lie somewhere in the middle.

After assembling your joint, allow the glue to set for around an hour (depending on the type of glue used). The glue will begin to change color and its consistency will be somewhere between it’s liquid and solid states. At this stage, you can use a sharp chisel to shave off the glue beads that have been squeezed out. Owing to that in-between consistency, the glue should come off more easily than fully dried glue, and without smearing like wet glue. After shaving the beads, remove any lingering glue residue with a damp abrasive pad. This will ensure residual glue smears don’t turn into an inconsistent finish.

You can also try applying masking tape along both edges of the glue joint. This means glue beads will stick to the tape rather than to the surface of the wood. This trick isn’t always practical and you’ll still likely have a few spots that need cleaning-up, but it can save some time.

In Summary

Crafting the perfect glue joint is not necessarily difficult, it just requires attention and process. Give due time to each step, and the result will be strong, flush joints that don’t show-up in your finish.