Gluing Festool Domino Mortises

[Darrin Davis]

I've had my Festool Domino Joiner for a few weeks now and always was wondering if there was a faster way to add glue to the mortise. After trying many methods such as small sticks, nails, etc. I kept wondering if there was a faster way. I decided to order some sucker sticks off eBay and much to my surprise it seemed to be the winner. The diameter size of the sticks along with the paper texture I was able to goop up glue on the end of the stick from a glue puddle and apply quickly to the mortise. These sticks seemed to work perfectly. It was a lot quicker and a more accurate application of glue than anything else I have tried. Try it. I bet you will be convinced.
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[Wade Lippman]

I have always put glue on the domino with acid brushes. I can't imagine putting it in the mortise. Am I on the wrong track?

[Dan Masshardt]

There's a guy on YouTube that tried different methods. He found that glue on both the domino and in the mortise added significant strength over just one.

Now, just one or the other is prob fine, but that indicates the both is the best overall option.

[Darrin Davis]

I always thought that you put the glue in the mortise so you can control how much makes it into the hole and stays in the hole instead of the glue scraping off the tenon while inserting.

[Dan Masshardt]

https://m.youtube.com/watch?v=e_gc64MlYzE

This guy has a whole bunch of other videos about the domino system as well.

[Steve Milito]

I always glue both sides of any glued surface. Small disposable brushes work great for applying glue to the mortise as well as the tenon..

[Wade Lippman]

I always glue both sides of any glued surface. Small disposable brushes work great for applying glue to the mortise as well as the tenon..

Really? I have never glued both sides, except rarely when they are complicated and I want to make sure glue hits both sides. What would you gain from that?

I have never had a domino fail in maybe 10 years, so I think one side is adequate.

[glenn bradley]

https://m.youtube.com/watch?v=e_gc64MlYzE

This guy has a whole bunch of other videos about the domino system as well.

Is it the difference in wood types that makes the domino not adhere well to the joined material? With "like species" tenon tests the wood fails, not the glue. In all of his examples the domino stayed whole and the glue joints failed. Maybe it was just the guy's method in the video as he was trying to demonstrate failure(?).

[Prashun Patel]

I glue both sides. Ironically, I find it trickier to glue the dominos without making a mess.

I've always used disposable watercolor or acid brushes for this.

[Andrew Pitonyak]

Really? I have never glued both sides, except rarely when they are complicated and I want to make sure glue hits both sides. What would you gain from that?

I have never had a domino fail in maybe 10 years, so I think one side is adequate.

I was told that Franklin (they make tight bond) recommend putting glue on both surfaces since it generally results in a better joint. I believe that the general concern is that when you apply the glue, the moisture is pulled into the wood. When the moister is pulled into the wood, the glue begins to cure and then you are more likely to have a "starved" joint.

I read something about this some time back. This was done using mortise and tenon joinery. I don't remember who did this, but, it was a person who is generally well known among wood workers and that person had always only glued one side. I don't think that it was Lang, but

http://www.popularwoodworking.com/articleindex/where-does-the-glue-go

Ultimately, you can compensate for this by using more glue on a single side. I have even had people tell me to put a very light coat of glue, then, add a second coat after seeing things pulled into the wood. Sometimes, I can see this happen quickly while gluing, so, then I add a bit more glue.

I have indeed chosen to only apply glue to one surface for some things, but I am always watching to see what happens when I apply the glue. I think that the worst case is a particularly "hungry" board and when you put the two pieces together, the dry side absorbs things too quickly. As you can personally attest to, however, people do achieve working results while gluing only one side. In the article or video that I had seen about this, the author stated that he had never used glue on both sides for a mortise and tenon and had never had a failure.... but, after doing experiments and cutting about the joints and seeing the results, now always adds glue to both sides. Wish i could find that article (or was it a video). The more I think about it, it was probably a blog post or magazine article.

I think that the general statement is "add just enough right where you need it" :D

https://www.finewoodworking.com/media/GlueUps.pdf

[Steve Milito]

Really? I have never glued both sides, except rarely when they are complicated and I want to make sure glue hits both sides. What would you gain from that?

I have never had a domino fail in maybe 10 years, so I think one side is adequate.

Never said that I could defend it. :p

[Richard Shaefer]

Lamello makes a glue bottle cap that applies glue to the sides of the hole.
it's meant for 4 mm biscuits, but it works well for Dominos too.

[mreza Salav]

Glue on both surfaces for sure, especially that the dominos are dry eough that they suck a lot of glue.
I apply glue into the mortise, then using the same brush apply to one half of the domino, when inserted the squeezed out glue is applied to the other half of domino.

[Erik Christensen]

I have glued up thousands and thousands of dominos and every one just had glue on the mortise - I use them so frequently that I can't see taking the time to put glue on both.

I have yet to have a single failure and when I make a mistake and need to pull a joint apart after even 10 minutes the wood is what fails

each to his own - i suggest that an extra domino or 2 (if you really need the strength) is much faster than than putting glue on all the dominos

[Chris Padilla]

I use the new'ish silicone brushes from Rockler. It has a little 'paddle' or 'spatula' on the end that works reasonably well for coating the walls of the mortise. I then tap in the dry domino.

In my course of then gluing up the other side of the joint, the half-exposed domino and the other mortise both get glue. At this point, the half-exposed domino will just get any excess glue wiped around it but I rarely add any extra to it.

[Wade Lippman]

To me, putting glue on the domino is so perfectly obvious that I couldn't understand how so many could be putting it in the mortise. I was going to contact Festool and get their opinion, when I remembered I had their extended manual on PDF.

When applying glue for the tenons, you can either apply
glue into the mortise slots, or spread a thin layer across the
Domino tenons. For applications where the tenon is the
primary structure holding the joint together, you should
apply the glue to the tenon. The Domino tenons have small
glue pockets and ridges that will hold glue as the tenon
slides into the mortise slot.

So, each to their own, but putting it on the domino is best.

[Dan Masshardt]

We know the that dominos are very tight, probably - prob one the reasons for the glue pockets.

If we apply glue to the tenon, it could push into the pockets and possibly less glue on the parts of the tenon without the pockets.

Because the tenon is, so tight, putting the glue in the mortise only could push a good amount of glue to the bottom. In front of the domino as it goes in.

The video test may have shortcomings but I won't dismiss it.

It seems to me the rankings from best to least would be

1. Both

2. Tenon (domino)

3. Mortise.

That being said, I'd think any of the methods would be fine for the majority of our projects.

[Dan Masshardt]

There are of course many different opinions and literature on this subject in general.

Here is an interesting 'test' dine with traditional mortise and tenon.

http://www.popularwoodworking.com/articleindex/where-does-the-glue-go

It might also natter what we're gluing into. For example, if the main surface of the domino happened to be contacting mostly endgrain. Even if not, we need to remember that the wood can absorb glue. In this article, things changed over an hour.

Because with the domino, there are two joints at every joint compared to tradition M&t) (if you follow me), getting it right might be even more important.

[jack duren]

To me, putting glue on the domino is so perfectly obvious that I couldn't understand how so many could be putting it in the mortise. I was going to contact Festool and get their opinion, when I remembered I had their extended manual on PDF.

When applying glue for the tenons, you can either apply
glue into the mortise slots, or spread a thin layer across the
Domino tenons. For applications where the tenon is the
primary structure holding the joint together, you should
apply the glue to the tenon. The Domino tenons have small
glue pockets and ridges that will hold glue as the tenon
slides into the mortise slot.

So, each to their own, but putting it on the domino is best.



Putting glue on the Domino alone is the least effective form of application ....

[Chris E Smith]

Thanks for posting your idea Darrin. I'm going to try the sucker sticks

chris

[Joe Jensen]

I use 1/4" acid brushes, most are 1/2". The 1/4" go in the mortise pretty easily. I also smear some on the domino as well. Pizzi makes a pneumatic glue system with specific nozzles for many joints including size specific dominos.
http://rangate.com/products?product=16