New Member- 1st Post- Domino Question

[Pete-OR]

I’m planning a project in which I’ll be using Domino 500 joinery. I’m fortunate to belong to a woodworking group that has equipment that exceeds the capacities of my shop and includes a Domino.

My question has to do with the advisability of pre-finishing the parts in advance of using the Domino to create the mortises. Basically I would first apply danish oil and a barrier coat of shellac, cut the mortises, glue up the assembly on the tenon faces and mortise cheeks only, scuff sand and then spray multiple coats of lacquer.

My initial research suggests that there is little or nothing to be gained by glueing the shoulders and I’m interested in learning if there are any other considerations.

Thanks in advance.

 

[ChuckM]

Snip.

My initial research suggests that there is little or nothing to be gained by glueing the shoulders and I’m interested in learning if there are any other considerations.

Thanks in advance.

That's correct. To avoid massive glue squeeze-out, some woodworkers choose to put glue only in the mortise and on the front part of the cheek of the tenon, but none on the shoulder.

 

[Birdhunter]

Unless you are perfect in applying the glue, you will get some squeeze out that will screw up your finish. I apply blue tape on either side of the joint line. It lessens the effect of glue squeezing out. Still, not a total fix.

 

[Pete-OR]

Birdhunter, good points. My plan to isolate glue distribution to only the mortise and tenon should mitigate the likelihood of squeezing on to the shoulders and beyond. I’ve also done some testing of damp rag removal of glue from cured shellac and found no evidence of residual glue. It would, of course, be of greater concern if the glue were to seep onto unfinished wood but the shellac barrier coat does a good job of protecting the wood for the final topcoats.

Fellow-birdhunter in Oregon

 

[peter halle]

[member=77479]Pete-OR[/member] ,

A word of advice - practice and practice some more on scrap before you tackle your project.  The domino looks so darn simple, but all of us here have read stories of a learning curve.

We'll be here to help with advice as you practice and beyond.

Peter

 

[Birdhunter]

I meant to add that Halfinchshy and New Brit have excellent YouTube videos on using the Domino.

 

[Crazyraceguy]

[member=77479]Pete-OR[/member] ,

A word of advice - practice and practice some more on scrap before you tackle your project.  The domino looks so darn simple, but all of us here have read stories of a learning curve.

We'll be here to help with advice as you practice and beyond.

Peter

Peter is correct on this. The tool itself and the concept of how it works are both very simple, but there are several adjustments that you have to be sure you changed when necessary. Keeping track of the reference faces is also quite important. Your tennons do not have to be exactly centered and obsessing over it can make you crazy, but it also reinforces the need to keep your reference faces straight.
Everyone has put a mortise on the wrong side or cut one all the way through something that they didn't intend to. It just happens and you would think that it's a rookie thing, but it can happen to seasoned users too. Familiarity breeds contempt as they say.

 

[ChuckM]

Good news is that many Domino errors can be fixed by plugging and gluing the mortises with a trimmed tenon, and restarting after the glue is cured. This is why helpful to keep the fence setting unchanged for as long as possible until after the dry fitting. Blow-outs are harder but not impossible to fix...it's a more time-consuming effort.

Speaking of familiarity, many safety errors are made because of it. I just bumped into a video in which the Youtuber (said to have 30 or 40 years of exp.) incurred a kickback (because he didn't use a ZCI). In the same video, he was seen ripping tall, narrow pieces on the table saw in an unsafe manner. What he needed was a tenon jig.

 

[ear3]

It depends on the pieces being joined whether you might be able to skip glue on the shoulder.  Even when it's just the loose tenon being glued, however, you're likely to get some squeeze out of the mortise is standard spacing from the board edge.  That's why the suggestion of blue tape is a good one -- it's initially a PITA because you have to dry fit everything first, but it does save a lot of time on the back end from cleaning the glue out of the joints.

 

[Lincoln]

There's no way I'd skip gluing the shoulders. I'd rather know that my joint has 100% glue coverage and have to deal with the minor inconvenience of squeeze out. I wouldn't pre-finish either, though your situation might dictate that you have to.

 

[ChuckM]

The second method (roughly) -- glue only in the mortise and about 2/3 on the cheek -- is how I usually do M&T as well as loose M&T including the Dominoes, producing none to very little glue squeeze-out. For edge jointing, however, I put glue on both mating edges then the mortises and dominoes as I don't trust the tenons alone for strength (I used glue alone before the Dominoes days).

The image shows why I wanted to avoid glue squeeze-out on the beaded profile. Sanding or scraping could flatten the beads.

 

[Birdhunter]

I’ve been using TiteBond Quick and Thick glue. It’s a lot thicker that the TB3 that I normally use. I see a lot less squeeze out with it. Downside is that it sets quickly.

 

[nvalinski]

I think I've strayed away from pre-finishing from the standpoint of the glue not adhering as well to an oiled surface. I usually have a decent amount of glue squeeze out that gets wiped off and ends up in the joint in between two pieces as well, and figured maybe the line in between the two pieces is absorbing some glue. That said... the end grain to side grain glued connection is adding next to nothing for strength, so maybe I'd have to reconsider, but I do wonder if it would make pushing the squeeze out more difficult.

 

[ChuckM]

Birdhunter, good points. My plan to isolate glue distribution to only the mortise and tenon should mitigate the likelihood of squeezing on to the shoulders and beyond. I’ve also done some testing of damp rag removal of glue from cured shellac and found no evidence of residual glue. It would, of course, be of greater concern if the glue were to seep onto unfinished wood but the shellac barrier coat does a good job of protecting the wood for the final topcoats.

Fellow-birdhunter in Oregon

I don't know about shellac as a protective coat against squeeze-out as my pre-finished projects were all done with stain and/or a topcoat of poly or varnish. These are examples of how others deal with excess glue:https://www.woodsmith.com/article/dealing-with-excess-glue/

 

[ChuckM]

Snip. That said... the end grain to side grain glued connection is adding next to nothing for strength, so maybe I'd have to reconsider, but I do wonder if it would make pushing the squeeze out more difficult.

There're two schools of thought on that. Some err on the safe side, while this fellow woodworker wrote an article preaching about as little as possible:
https://www.finewoodworking.com/2008/05/01/prevention-is-best-cure-for-glue-squeeze-out

 

[Crazyraceguy]

ChuckS, that last pic in the series is just plain crazy.
I have seen plenty of flooring guys do some pretty sketchy looking stuff "free-hand" on job-site saws, but those are fairly thin pieces and laying flat.
That vertical "tennon" cut free handed like that is foolhardy and stupid.

The old saying about how you don't get everything you ask for, does not apply to trouble. You ask for trouble and generally you get it, usually more than you wanted.