How to get epoxy into mortises without making a mess

[David Stone (CT)]

Today I was gluing up a table and used epoxy for some of the joints because I needed the safety margin of a long open time for the secondary parts while I focused on getting the legs and aprons closed up with Titebond. This raised the question of how to get the epoxy into mortises--domino slots, in this case--without risking hard-to-clean-up drips or wispy threads finding their way onto the surrounding areas of the workpiece. With PVA, this is pretty trivial, using a Fast Cap GluBot or similar applicator. My experience with epoxy is very limited but enough to know I can make a mess with it and needed something better than a finish nail dipped in epoxy to place it. In the event, I used an industrial syringe as pictured, coupled with an acetone-soaked paper towel to wipe the tip between applications and remove globs building up on the needle before they could fall onto my work. This proved to work pretty well (though I might try to get a bigger gauge needle in the future). But it left me wondering: what methods do those who often use epoxy in joinery applications find 485140work best for placing the glue?

[Phillip Mitchell]

Tongue depressor or acid brush depending on how much and how confined. You could also pour a certain amount into bottom of each mortise and use either of the above to spread onto the mortise walls, etc. Just a couple options.

[Tony Shea]

I also use syringes once in a while for this purpose. West system sells syringes, much more basic than the syringe you show. Check out West System 807 syringe. You can cut the tip to whatever size you need for your application.

[Stan Calow]

Without looking into it further, how do you get the viscous epoxy into the syringe, without making a mess?

I do a lot of epoxy M/T joints, and its always a problem, chasing those runs and squeeze out. I Make things up pretty good, but its still a problem. I use the "popsicle sticks" they sell at craft stores. They have some that are very thin, 1/4" or so, for narrow mortises.

[Patrick Varley]

I like the syringe method, as well.

I switched to plastic luer lock dispensing tips: https://www.fisnar.com/products/dispensing-accessories/dispensing-tips/tapered-dispensing-tips/

I prefer these since you can trim back the tip even further to get a larger opening for more viscous materials.

Stan: I usually mix small amounts (of West Systems) in plastic dixie cups, then remove the plunger and load the epoxy into the barrel directly. With the small amount and small cup, it usually pours without too much mess.

[Mike Henderson]

And bevel the inside top edge of the mortise so the excess glue has somewhere to go and doesn't squeeze out.

Mike

[David Stone (CT)]

Without looking into it further, how do you get the viscous epoxy into the syringe, without making a mess?.

The epoxy was too viscous to draw up through the needle, as is possible with thin liquids. But it flowed well enough for me to pour it out of a small mixing cup into the top of the syringe tube (with the plunger pulled out). With a little care, there was little spillover onto the outside of the syringe or my gloves and what mess did occur was safely away from the workpieces and easy to clean up with a little acetone.

[Jamie Buxton]

Only put glue in the mortise, not on the tenon. Excess glue gets pushed inside the mortise, not out on to visible surfaces.

I use a putty knife as a spatula to put the glue in the mortise. If I need a narrow spatula, I use a 6” machinists rule.

[John TenEyck]

Shop made tongue depressor works fine for me. You can clean up squeeze out with white vinegar, and it won't damage prefinished parts like acetone, lacquer thinner, etc will.

John

[Gregory King]

Premix and use a few Q-tips.

[Lee Schierer]

Cover the mortise with painters tape. Then use a scalpel to remove the tape over the opening. Work as much epoxy into the mortise as you want. Pull off the tape and complete your assembly.

[John Kananis]

Going back to syringes, look at electronics supply houses. They make large gauge tips and syringes (fat round ones) for solder paste and very viscous Flux. Much cheaper than other sources, much.

[Bernie Kopfer]

Checkout Monoject 412 washout syringes. We used them in dentistry to irrigate surgical sites etc. They are readily cheaply available online I use them to put glue in precise locations both epoxy and Titebond. They also work great for placing caulk in door, floor and window trim.

[John Pariseau]

I just did this for two bolt holes in concrete. I had some leftover grout bags - mixed my epoxy in the bag, cut the tip to size, dispense. Can also use ziploc bags - just use a heavier duty bag and not the cheap sandwich bags.

Edit: this won't work well for thin epoxies, of course.

[Curt Harms]

Cover the mortise with painters tape. Then use a scalpel to remove the tape over the opening. Work as much epoxy into the mortise as you want. Pull off the tape and complete your assembly.

That's what I do, even with PVA glues. No surprises at finishing time that way. Takes a bit longer and costs a bit but for low volume usage it's fine.

[Charles Lent]

I also surround the jointed surfaces with blue tape. Dry assemble the joint, apply the tape, then dis-assemble for gluing. Any excess glue ends up on the tape, which is peeled off after the glue firms up, but is not dry.

Charley