tools & accessories For Applying Glue
My office is in the studio/shop where we film the Woodsmith Shop and other videos. The best part is I can get up from my desk and do a little woodworking whenever I want to. Designer John Doyle’s desk is behind mine. As a result, we chat about shop projects a lot.
One of those projects is the assembly center on page 26. That came from some shortcomings of a clamp cart we have on the set. The cart holds a lot of clamps, but doesn’t really have a place for the other gear necessary when it’s time to glue up a project. As we were talking about what a full-service assembly cart should contain, it seemed like a good idea to take a closer look at some of the tools and accessories available for gluing up projects.
BEYOND FINGERS.
I’ve used a finger to spread glue (and scraped the excess off on the bottom of the bench). As convenient as that is, it does get messy. Most of the time, I use some kind of brush. The upper right photo on the next page shows some of the brushes I gathered from around the shop here.
ACID FLUX BRUSH.
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| Pinch the bristles of an acid flux brush to spread them out. Then trim them to a rounded profile. |
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| The round shape gives you more control for spreading glue on flat surfaces or confined joinery details. |
When I started woodworking with my dad, he used acid flux brushes to apply glue. They’re popular around here, too for good reason. The brushes are inexpensive yet surprisingly durable.
As with all good tools, some modifications make them work even better. The brush needs a two-bit trim in order to spread glue evenly and where you want it. The lower left photo shows the look I’m after. This rounded shape provides better control.
GLUE BRUSHES.
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| Left to right: silicone glue brushes, metal-handled acid flux brushes, and round dedicated glue brushes. |
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| The small round glue brush tucks into narrow grooves to get a better glue bond. |
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| The paddle end of the Titebrush scrapes away glue squeezeout after the clamps go on. |
Until recently, I didn’t know that dedicated glue brushes were a thing (thank you, Chris Schwarz). The Torrington company makes a line of brushes that look like small paint brushes.
The bristles are held in a round ferrule, rather than the flat flux brush. There are two sizes that work well, the model 122 and 124. The smaller one puts glue in narrow grooves or between dovetails. The larger version handles edge gluing, rabbets, and tenons better.
SILICONE BRUSHES.
In the last few years, silicone brushes jumped in as the newest glue tool. These seem descended from kitchen basting brushes. The thick bristles hold a lot of glue and do well for spreading on larger surfaces.
Smaller round brushes are available as well. However, I don’t find that those to hold much glue. In addition, the brush is still too large to fit into the kinds of details in the work I do, though it may work just fine for you.
One of the advantages of the silicone form is that dried glue peels right off. Try it just once. Allow the glue to dry in the brush, then (carefully) pull out a honeycomb-shaped glue clump. It seems like a fun trick, it should be a last resort rather than standard practice. It’s all too easy to yank out a bristle or two along with the glue.
BRUSH CARE.
This is a good time to talk about taking care of whatever glue brush you use. It’s too easy to consider acid brushes and the glue brushes as disposable. Just like other tools, they’ll last for a long time with simple maintenance.
After every gluing session, rinse out any type of brush with warm water. A little dish detergent helps, too. If your shop is like mine and doesn’t have running water, then at least keep a jar of water nearby. Then you can soak the brush until it’s time to go back inside the house. I’ve had brushes last several years with this routine.
Heat is a Friend
I often use liquid hide glue for my furniture projects. The longer working time is the main reason. The color of the glue matches wood tones better, in my opinion. The only issue is that it feels like applying caramel sauce.
The solution is to heat it up. I put glue in a plastic cup (from a lunchbox fruit snack) that fits over a glass filled with hot water. This setup keeps the glue warm and runny. This way you can apply the right amount of glue with less hassle.
OTHER APPLICATORS
There are some glue-spreading jobs that benefit from specialized tools. To be honest, I have trouble in this area. Glue tools and gewgaws litter woodworking catalogs and sites. But just because a specialized tool exists, it doesn’t mean you necessarily need it.
All that to say is tread carefully when you venture away from your precious, basic brush. What follows here are a few examples that represent a much larger group of gear.
LARGE SURFACES.
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| Avoid the siren call of gimmicky solutions and use a foam roller and roller cage to spread glue across large surfaces. |
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| A bottle combined with a roller attachment eliminates the need for a separate spreading tool. |
Spreading glue on large surfaces with a small brush is like cutting the grass with scissors. I go with a pour-and-spread approach. Shop manager Marc Hopkins told me his setup. He has a 4" roller frame. Then he cuts down an 8" thin black foam roller, as shown in the photo above. This inexpensive kit makes quick work of spreading glue for veneer or laminating wide boards for benchtops.
SILICONE AGAIN.
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| This silicone spreader has teeth to disperse glue uniformly for laminating panels or veneering. |
The silicone tool folk have their own solution in a comb-like spreader. The flexible teeth distribute glue over a large area and the crop-circle patterns give you a good gauge for even coverage. Here again, the spreader can be cleaned with warm water or the dried glue can be picked out of the teeth like raspberry seeds.
JOINERY SPECIALISTS.
Grooves, rabbets, and tenons play well with glue brushes. Some joinery options present challenges. Dowel holes, biscuit slots, or small loose tenon mortises are a few that come to mind.
The small round silicone brush with a Q-tip like end, aids in spreading glue along a dowel hole rather than simply pooling at the bottom.
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| The pebbled surface of this spreader butters a biscuit slot evenly. |
The “brush” shown has a duckbill to spread glue all around a biscuit slot. As a biscuit aficionado (yes, we exist) this one tempts me, a lot. There are similar brushes designed around Festool’s Domino loose tenons as well (refer to sources).
BOTTLE UPGRADES
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| This nozzle is shaped to match a biscuit slot. The small tube limits the flow of glue. |
For the most part, a glue bottle is simply a storage container. Several makers seek to combine the brush with the bottle to create an all-in-one applicator solution. What you have to do is replace the nozzle. Again, the options are numerous.
IS GLUE A CONDIMENT?
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| This clever design dispenses glue only when you squeeze the sides. Trim the nozzle to suit your needs. | Decant glue into a condiment bottle with a small nozzle. This gives you better control over how much glue gets applied to your project parts. |
If you’ve ever been flummoxed by a stock glue bottle (clogged nozzle, too much glue, wrong size bottle) rest assured there are options. One that I’ve adopted is shown above. It’s a squeeze bottle with a narrow tip. Gravity pulls the glue back in and gives you control of how much comes out.
The upper right photo shows a repurposed idea. Pick up a condiment bottle from a dollar store. The small tip gets glue into tight spaces and is easy to dispense.
CUPS & TRAYS.
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| Pouring glue into a tray makes it easier to apply with a brush. This silicone tray lets you peel off dried glue. |
About half the time, I pour glue into a smaller container before brushing it onto a joint surface. I often reuse cleaned out snack cups. You can also get silicone trays and cups.
All in all, consider glue application just as you do other tasks. Find a few reliable tools and get to work with confidence.
You need a Glue Kit
In addition to clamps and a deep breath, you should have your gluing gear ready to go before you jump into project assembly. What I show here are the minimum essentials.
What type of glue you use is really a matter of personal preference. Just be sure it’s fresh and that the nozzle is clear. I hold a small plastic cup of glue in one hand. The other holds a brush to efficiently apply glue and minimize errant drips on the project.
The cup of water isn’t for drinking. It’s for on-the-go cleanup. If I find a drip, or some squeezeout, I take care of it. A damp shop rag gathers runs and drips. For squeezout in a corner, I scrub it away with a wet toothbrush. Follow up with the cloth to sop up excess water. By the way, I prefer that the water is warm to hot. This lifts away glue rather than smearing it around.
