Festool Domino Question

[Mike Henderson]

For those of you who use a Festool Domino, what do you use to spread glue inside the mortise? I always want to make sure the sides of the mortise are well covered.

I've been using those coffee stirrer sticks like the ones you get at Starbucks but maybe there's something better.

Mike

[Bill McNiel]

I use cheap Flux brushes, temporarily stored in a plastic cup of water during a prolonged glue-up and then trashed.

[Prashun Patel]

I also use flux brushes.

[Matt Day]

Yup, been using these cheap HF brushes for glue for years.
https://www.harborfreight.com/36-pc-12-in-horsehair-bristle-acid-shop-brushes-61880.html

[Jamie Buxton]

I use a 6" machinist's scale. It is stainless steel, and about a half inch wide. It washes off easily, so there's nothing thrown away. It smears glue nicely on the flat sides of the mortise. And, of course, I use it as a measurement tool too. I don't worry about spreading glue on the rounded ends.

[Jim Tobias]

I use these. They hold about the right amount of glue and are cheap enough to be disposable.

https://smile.amazon.com/dp/B07WYY8JHP/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B07WYY8JHP&pd_rd_w=7FEOS&pf_rd_p=48d372c1-f7e1-4b8b-9d02-4bd86f5158c5&pd_rd_wg=Yb9gv&pf_rd_r=E27YERZTQ418YFYDAM9P&pd_rd_r=f6fc7781-4735-4275-b316-e7cd74082be5&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzQkc2TVRJNjM4RUozJ mVuY3J5cHRlZElkPUEwMzc0MTQxMTEzNDBWSzVNS0dTTiZlbmN yeXB0ZWRBZElkPUEwNzAwOTQ3MkwxOTlVTDQ1TlBYNiZ3aWRnZ XROYW1lPXNwX2RldGFpbCZhY3Rpb249Y2xpY2tSZWRpcmVjdCZ kb05vdExvZ0NsaWNrPXRydWU=

Jim

[ChrisA Edwards]

Guess I'm a bit lazy, I just put glue on both sides of the domino and push it in the mortise. For the protruding tenon, I brush glue on it as I glue that edge.

[Frank Pratt]

I use cheap flux brushes, but there's no need to toss them after use. A thorough cleaning takes about 10 seconds & they will last many glue ups. It's not the cost as much as a desire to throw out less stuff that can be reused.

[Matt Day]

I use these. They hold about the right amount of glue and are cheap enough to be disposable.

https://smile.amazon.com/dp/B07WYY8JHP/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B07WYY8JHP&pd_rd_w=7FEOS&pf_rd_p=48d372c1-f7e1-4b8b-9d02-4bd86f5158c5&pd_rd_wg=Yb9gv&pf_rd_r=E27YERZTQ418YFYDAM9P&pd_rd_r=f6fc7781-4735-4275-b316-e7cd74082be5&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzQkc2TVRJNjM4RUozJ mVuY3J5cHRlZElkPUEwMzc0MTQxMTEzNDBWSzVNS0dTTiZlbmN yeXB0ZWRBZElkPUEwNzAwOTQ3MkwxOTlVTDQ1TlBYNiZ3aWRnZ XROYW1lPXNwX2RldGFpbCZhY3Rpb249Y2xpY2tSZWRpcmVjdCZ kb05vdExvZ0NsaWNrPXRydWU=

Jim

Jim, those look handy, thanks for the link.

[Bob Hinden]

I use Glue Spreaders like these (https://www.amazon.com/dp/B01H204Y3E/ref=cm_sw_em_r_mt_dp_U_8a95EbCFVT711), you can get them at a number of places. Works fine except for very deep mortices. Nothing to throw out.

[George Yetka]

depends on whether i oversize the hole or not If i dont I just squirt some on the domino and a bit in the hole. If it is oversized I go flux brush

[Jim Becker]

Honestly...I mostly just dribble some in so it reasonably coats both sides, but when I want an even coating, I use one of the disposable acid brushes I buy for glue applications. I'm about to replace those with a reusable silicone brush marketed by the Titebond folks.

[Ralph Okonieski]

I use these.

https://www.amazon.com/gp/product/B01NBTV5V2/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

[Andrew Hughes]

I use a plastic blue glue spreader. I like spend about 2 seconds per hole with just the right amount of glue so I don’t get a lot of squeeze out. Ive found Sometimes squeeze out can prevent a joint from closing.

[Cliff Polubinsky]

Go to Rockler and search for glue paddle. They have a couple of styles made of silicone so the dry glue peals off. On the brush/paddle combination the paddle seems to have been designed for a domino mortise.

Cliff

[Ken Platt]

I use the same plastic paddle style glue spreaders that Bob Hinden put in his link. I think I got mine from Lee Valley, but I can't find them there now, so I might get some of those from Amazon just to have extra. Of course, I've been using the same couple of them for years now...just wipe off after a glue up. I put a small amount of glue in a little plastic cup, then just dip the spreader in there, then into the mortise. I am compulsive enough that I also put a smear of glue on the tenon - this somewhat gets squeegeed off when I put the tenon in the mortise, and then I use the spreader to wipe that little bead of glue onto the rest of the tenon. It sounds more complicated than it in practice.

Anyhow, those little plastic spreaders are perfect.

Ken

[glenn bradley]

I also used the little plastic spreaders. I bought a set of six or so from Lee Valley many years ago. I’m still using the first one.

[Dave Sabo]

I don't worry about it. It's called a loose, or floating tenon. If glued fast it doesn't really meet that description anymore.

Of course glue gets into the mortices when I spread it , but I don't worry about that either.

[Richard Wile]

I have a box of flat toothpicks nearby all the time, squirt glue into the mortise and spread around with flat end, gets perfect coverage,and goes in my burn box. Much more economical than glue brushes to glue a couple of dominos, also perfect for mortises,or anywhere a little dab’ll do ya!

https://www.amazon.com/dp/B014PYMEMS/ref=cm_sw_r_cp_tai_mMk6Eb8SHMPS0 (https://www.amazon.com/dp/B014PYMEMS/ref=cm_sw_r_cp_tai_mMk6Eb8SHMPS0)

[Jim Becker]

I don't worry about it. It's called a loose, or floating tenon. If glued fast it doesn't really meet that description anymore.

Of course glue gets into the mortices when I spread it , but I don't worry about that either.

They are loose primarily because they are just a separate piece that's "loose" from the two components to be joined. Otherwise, most folks don't make them physically loose. :) In the case of the Domino, they are pretty darn tight even without glue! Took a few good wacks to separate this dry fit...and that's only one 10mm Domino is a "non-loose" mortise.

435132

[Frank Pratt]

I don't worry about it. It's called a loose, or floating tenon. If glued fast it doesn't really meet that description anymore.

Of course glue gets into the mortices when I spread it , but I don't worry about that either.

Without having thorough glue coverage in the mortise & on the tenon the joint looses much of its strength.

[Jim Dwight]

I used these: https://www.rockler.com/rockler-silicone-glue-brush. I use the paddle end in the mortise and put a little on the tenon with the brush end. I used to use acid brushes and I think they would work fine but I have found these little applicators to be handy. I have several. The glue comes off them well but only after it dries. Especially the brush needs several days to dry. I've tried only putting glue in the mortises but cut one apart afterword and was not happy with the coverage. I think brushing a little on the tenon is a better idea.

Festool tenons are 2-3mm shorter than the stated length. That helps you avoid locking up the joint due to glue collecting at the bottom of the mortise.

[Jeff Ranck]

I've been using the same acid brush for a very long time. I cut off a bit of the brush so the bristles aren't too long. Make sure that none of the bristles come out and simply drop it in a cup of water after use. A little washing at the sink and it is good to go for the next time.

[Jim Becker]

Like Jeff, I will wash out an acid brush so it can be used over an entire day...when I remember to have some water available for the purpose, of course. :)

[Dave Sabo]

They are loose primarily because they are just a separate piece that's "loose" from the two components to be joined. Otherwise, most folks don't make them physically loose. :) In the case of the Domino, they are pretty darn tight even without glue! Took a few good wacks to separate this dry fit...and that's only one 10mm Domino is a "non-loose" mortise.


As you may have noted (and omitted) they are also called "floating" tenons - which suggests not fixed. And I'm well versed in them as well as traditional ones. Making them loose would defeat most of the purpose of the joint in the first place, as the strength is in the fit.



Without having thorough glue coverage in the mortise & on the tenon the joint looses much of its strength.

Sorry Frank , but I have to strongly disagree with you here. Without glue it will lose some strength certainly; but not much of its strength as you characterize.
M&T joints have been around for millinnia, long before adhesives existed. Their popularity remains today because the joint is strong long term without adhesive. And because they're not easy to execute well without a modicum of skill, they've become a staple of craftsmanship. Look at any modern timber framed structure today - lots of mortise and tenon joints. The loads on those are immense, and framers aren't using liquid nails or even titebond as an insurance policy or part of the strength equation.

Now, I'm not looking to start a revolution by advocating everyone throw away their glue brushes and to stop using glue on M&T joints . I am saying that worrying if you have enough glue spread out consistently with the perfect M&T brush isn't really necessary. A little bit on the tenon would be plenty good, and and any real amount in the mortise Jim shows and describes above could prove problematic. If you're requiring glue to keep your M&T joint together, you should probably spend more time learning how to make a better joint that searching for the ideal mortise glue spreader.

[Doug Dawson]

As you may have noted (and omitted) they are also called "floating" tenons - which suggests not fixed. And I'm well versed in them as well as traditional ones. Making them loose would defeat most of the purpose of the joint in the first place, as the strength is in the fit.

Sorry Frank , but I have to strongly disagree with you here. Without glue it will lose some strength certainly; but not much of its strength as you characterize.
M&T joints have been around for millinnia, long before adhesives existed. Their popularity remains today because the joint is strong long term without adhesive. And because they're not easy to execute well without a modicum of skill, they've become a staple of craftsmanship. Look at any modern timber framed structure today - lots of mortise and tenon joints. The loads on those are immense, and framers aren't using liquid nails or even titebond as an insurance policy or part of the strength equation.

Now, I'm not looking to start a revolution by advocating everyone throw away their glue brushes and to stop using glue on M&T joints . I am saying that worrying if you have enough glue spread out consistently with the perfect M&T brush isn't really necessary. A little bit on the tenon would be plenty good, and and any real amount in the mortise Jim shows and describes above could prove problematic. If you're requiring glue to keep your M&T joint together, you should probably spend more time learning how to make a better joint that searching for the ideal mortise glue spreader.

Did you know that Lincoln Logs were invented by the son of Frank Lloyd Wright?

[Mike Henderson]

As you may have noted (and omitted) they are also called "floating" tenons - which suggests not fixed. And I'm well versed in them as well as traditional ones. Making them loose would defeat most of the purpose of the joint in the first place, as the strength is in the fit.




Sorry Frank , but I have to strongly disagree with you here. Without glue it will lose some strength certainly; but not much of its strength as you characterize.
M&T joints have been around for millennia, long before adhesives existed. Their popularity remains today because the joint is strong long term without adhesive. And because they're not easy to execute well without a modicum of skill, they've become a staple of craftsmanship. Look at any modern timber framed structure today - lots of mortise and tenon joints. The loads on those are immense, and framers aren't using liquid nails or even titebond as an insurance policy or part of the strength equation.

Now, I'm not looking to start a revolution by advocating everyone throw away their glue brushes and to stop using glue on M&T joints . I am saying that worrying if you have enough glue spread out consistently with the perfect M&T brush isn't really necessary. A little bit on the tenon would be plenty good, and and any real amount in the mortise Jim shows and describes above could prove problematic. If you're requiring glue to keep your M&T joint together, you should probably spend more time learning how to make a better joint that searching for the ideal mortise glue spreader.

I don't really understand your position. Let's say that I make a table with an apron attached to the legs with M&T joints. Now, let's look at one of those joints, a leg and one section of apron. I made the tenon on the apron and the mortise on the leg, and I fit them together very accurately and tight.

Now, before I use any glue, I grab the bottom of the leg and the end of the apron and pull them together, like a scissors. The tenon will come out of the mortise very easily. If I put the table together without gluing the M&T, the first time I dragged the table across the floor, the legs would come off.

If you want strength in a M&T joint you have to use glue. And the glue joint is stronger than the wood.

My experience is that you get the best glue joint in a M&T joint by applying glue to the sides of the mortise AND to the sides of the tenon. If you really do a tight fit of a tenon to a mortise and only put glue on the tenon, a lot of the glue is wiped off as you push the tenon into the mortise. You have good glue on the surface of the tenon but only spotty glue on the sides of the mortise, and that hurts the strength of the joint.

And just a Domino point, even when you use the narrow setting for your mortise, the mortise is a tiny bit wider than the tenon so that excess glue can come up alongside the tenon. The Festool people designed it that way for that reason. They also cut the mortise a bit deeper than half the length of the domino so that there's some space at the bottom of the mortise.

Mike

[Doug Dawson]

I don't really understand your position. Let's say that I make a table with an apron attached to the legs with M&T joints. Now, let's look at one of those joints, a leg and one section of apron. I made the tenon on the apron and the mortise on the leg, and I fit them together very accurately and tight.

Now, before I use any glue, I grab the bottom of the leg and the end of the apron and pull them together, like a scissors. The tenon will come out of the mortise very easily. If I put the table together without gluing the M&T, the first time I dragged the table across the floor, the legs would come off.

If you want strength in a M&T joint you have to use glue.

No, you just have to pin it.

[Mike Henderson]

No, you just have to pin it.

Pinning is not as strong as glue and the pin shows. If you put a lot of force on a pinned M&T, the tenon breaks at the location of the pin, which is often towards the back of the tenon.

If you don't have glue, pinning is better than nothing but not as good as modern glue. Our ancestors pinned because the didn't have good glue.

To get sufficient strength you have to glue loose (or floating) tenons, especially Domino tenons.

Mike

The only advantage I can see to pinned tenons is that you can drive the pin out and release the joint.

[Doug Dawson]

Pinning is not as strong as glue and the pin shows. If you put a lot of force on a pinned M&T, the tenon breaks at the location of the pin, which is often towards the back of the tenon.

If you don't have glue, pinning is better than nothing but not as good as modern glue. Our ancestors pinned because the didn't have good glue.

It is ridiculous to say that you don't have to glue loose (or floating) tenons, especially Domino tenons.

Mike

The only advantage I can see to pinned tenons is that you can drive the pin out and release the joint.

Also, repairability. And also, in some cases, resilience. (Assuming the joint was intelligently constructed.)

It all depends on how strong the joint _needs_ to be, which people often overlook when comparing the merits of joints.

[Mike Henderson]

Anyone who has a Domino has dry fit their joints and then taken them apart with nothing but their hands before putting them together with glue. It's patently obvious that a M&T joint without glue is not reliable - it's not going to stay together.

Mike

[Prashun Patel]

I am with Mike. This is the first time I am seeing that glue on a floating tenon is unnecessary. I understood the name to come from the fact that it’s not integral to either piece, not that it’s intended not to be glued.

[Jim Becker]

Anyone who has a Domino has dry fit their joints and then taken them apart with nothing but their hands before putting them together with glue. It's patently obvious that a M&T joint without glue is not reliable - it's not going to stay together.

Mike

Um...I can't often get dry fit Domino joints apart merely with my hands, but a few blows with a soft mallet does the job. :) I had to do that this week with my window project prior to glue-up. Those suckers were tight. Which is how I wanted them. But I absolutely agree that glue is essential for the final assembly for maximum benefit.

[Doug Dawson]

Anyone who has a Domino has dry fit their joints and then taken them apart with nothing but their hands before putting them together with glue. It's patently obvious that a M&T joint without glue is not reliable - it's not going to stay together.

Nobody in their right mind would think that an unglued Domino is a strong joint, used as a joint. (There could be pathological exceptions.)

But your claim that a properly pinned M&T joint is not reliable is just plain weird, and ignores the history of the craft. I have stuff that I built decades ago using carefully thought out joinery, that never saw the plague of glue, that is still seeing rough use today, and has held up very well, under arguably extreme conditions.

Let’s not even get into the more interesting asian joinery methods, where you might not even think about this stuff.

[Kevin Jenness]

"the plague of glue"?

You lost me there. Sure, pinned tenons, properly designed, are effective. True enough, timber-framed structures are built with unglued mortise and tenon joints- at least in this country though the main structure is augmented with angle braces, without which the whole affair would be suspect. If you repair timber frames for a living as my son does you will find that a majority of the pinned angle brace tenons are broken from tension forces, showing that the braces are primarily effective in compression. This doesn't prove that pinned joints are ineffective, but it does show that the joints typically don't have enough cross section to be pinned effectively. The same is true of many furniture joints, and that is where glue comes in. Plus, there are many situations where pins would be visually inappropriate, or high stress joints as in chairs where glue would add strength to a pinned joint. If I am using a m&t joint that requires glue to be effective I thoroughly coat both surfaces to ensure maximum strength.

[Jim Becker]

Comon' folks..."different strokes" applies here. There absolutely is great joinery that doesn't leverage any glue. But glue is a common and valid method for securing a wide variety of joinery methods, too, and in those cases when used properly, it adds to the strength to some extent; sometimes just a little and sometimes quite a bit.

[glenn bradley]

What an interesting bit of conversation. Certainly a different approach to M&T, floating or not, than I am used to. I take advantage of the long grain mating surfaces that M&T provide to secure a joint and resist movement. Until now that is all I had considered it for except when making things purposely loose like the M&T at the rear of a drawer frame (dust frame) in a carcass for example.

I have a Domino. It is an additional way to mortise but, certainly hasn't replaced more typical methods used in my shop. When using it for alignment I glue up similar to the way Dave S mentions since the Dominos are acting like a spline or biscuit for alignment, not for strength in the long grain to long grain glue joint. All in all a refreshing look at a traditional joint and the thread certainly took me through a bit of mental exercise. I'll continue to glue my M&T joints that are used for strength though ;-)

Like other joinery methods, sometimes the M&T becomes a design element. In this case the through tenon, wedged tenon or pinned tenon is an aesthetic element as well as a construction element. I agree that pinned tenons reduce the strength BUT, also agree that we need to consider "how strong does it need to be?" when talking about stronger or weaker joinery. We certainly don't want things falling apart but, delicate pieces are part of our craft.

[Jim Tobias]

I would venture to say that some of this disagreement about "tightness: of domino joints (or loose tenon joinery) is about relative humidity in the region you live. I live in NC and humidity here fluctuates greatly from east to wet within the one state. My shop is heat and humidity controlled, yet I always have to shave/sand/plane dominoes to get them in for a dry fit. I have stuck them in the microwave a minute or so to dry them out and stored them in plastic sealed bags and still occasionally have to sand/sand/plane them to get a dry fit. Quite often I have to use a rubber mallet to release a dry fitted domino.
So, maybe, glue is the equalizer across humidity zones to ensure a permanent hold?

Jim

[Prashun Patel]

I have never read any suggestion not to glue a floating tenon except for cross grain joint that required expansion room. Even then, the user always has glued (or drawbored) at least one side of each tenon and both in the center.

Festoon themselves have made knock down tenons for applications to be taken apart.

Even in Windsor chairs they don’t glue the tenons into the mortise but at least wedge them, and glue the wedge. Having made a couple of these, i have experienced that even here the joint can loosen through the seasons. The tapered socket is designed to address this and to re-seat the joint as the user sits.

The same would happen to a traditional mortise and tenon. No matter how accurately you saw or fit the joint, there is a significant possibility it will loosen over changing seasons without additional mechanical reinforcement or glue.

[Kevin Womer]

I use these:
https://www.rockler.com/rockler-glue-paddles-3-piece-set

[Jeff Booth]

I use ~3 mm diameter bamboo skewers from the grocery store. I can cut a skewer into three 100mm long glue applicators at the baby bandsaw, I never use the skewer point, it’s useless but the squares ends are great. I dribble the glue into all of the mortises, then each one I spin the skewer at the bottom to pick up the glue and keep spinning while moving it in the air because that doesn’t allow a drop to fall off, then I can wipe it along mortise sides and the half circle ends. I do all mortises, then I use the skewer to wipe into then remove almost all glue from the domino itself, there are pressed in areas in the domino face I am trying to fill, but any extra glue on the domino just becomes squeeze out.