How do you glue dowel pins and Domino tenons?

[Cary Swoveland]

I'd like to speed up the application of glue, and reduce glue squeeze-out, when using fluted dowel pins (generally with the Dowelmax) and (Festool) Domino tenons. Suggestions? Among other things, I'd like to know if anyone has tested the strength of joints depending on whether glue has been applied to both the tenon and mortise, or to just one of the two.

Cary

[Chris Padilla]

Cary,

One thing I do with M&T joints (floating or not), is to NOT glue the shoulder area of such a joint since it is end-grain to long-grain. You won't get much strength there and it will help with squeeze out and time cleaning and potential finishing issues in that area. Does this help you or not (assuming you buy it)?

I still put glue on both to ensure I have gotten good coverage everywhere.

[Bruce Pennell]

I've seen the domino question come up on Festools site, one guy use's the dip and stick method. Take the domino dip in bowl of glue and stick it home. Thats how he sped up his production. I am a hobbiest so I just brush on both sides myself, not worried about speed.

[Cary Swoveland]

Cary,

One thing I do with M&T joints (floating or not), is to NOT glue the shoulder area of such a joint since it is end-grain to long-grain. You won't get much strength there and it will help with squeeze out and time cleaning and potential finishing issues in that area. Does this help you or not (assuming you buy it)?


Chris,

I was using the terms "tenon" and "mortise" to apply to dowels/Dominos and dowel holes/Domino mortises, respectively. I can see why that may be misunderstood. For traditional M&T joints, I don't glue the shoulders either.

Cary

[Chris Padilla]

Chris,

I was using the terms "tenon" and "mortise" to apply to dowels/Dominos and dowel holes/Domino mortises, respectively. I can see why that may be misunderstood. For traditional M&T joints, I don't glue the shoulders either.

Cary

Yes, I know, but I still do the same practice if these joints are of a cross-grain variety regardless if I use dominos or dowels (or M&T). If the joint is long to long, then of course you glue it and the dowels or dominos are mostly there for alignment purposes (like biscuits).

I apologize for going off on a bit of a tangent as I thought there might be a slim hope it would help your situation. No biggie! :)

[Peter Quinn]

I wouldn't use fluted dowel pins for structural joints in any application. I use spiral dowels for glue joints and fluted for non glue allignment applications or for mechanical strength where screws hold the joint in place.

I drill dowel holes a 1/16" deeper than the dowel length on each end to give some room for excess glue. Add glue to the first dowel hole only, then plunge the pin in and partially out a few times quickly to spread glue on the dowel, working the squeeze out from this up the exposed part of the pin with a small brush. I glue the second hole conservatively, removing excess with a thin glue brush before assembling the joint.

It takes a bit of pratice and restraint to realize how much glue is sufficient for coverage without excess squeeze out. I made doors commercially for a few years using amoung other methods cope/mold with dowel reinforcement. Always dry fit everything as if it were the actual glue up and have clamps/cauls ready to go. A complex glue up sure gets my heart racing!

I always use dowels that are .008" undersized relative to the drill bit. At work we custom ordered undersized pins in bulk, I don't know of any retailer who caries them this way.

Think of it this way: If the hole is 1/2", and the proper glue film is .004" X2 faces for a total of .008", then how are you supposed to get a .500" dowel and glue in a .500" hole? One major dowel jig manufacturer I contacted recommended I get a bigger hammer or some sandpaper! I recommended they get better enginering. If you have to bang the dowels in with a hammer you are starving the glue joint, will get excessive squeeze out, suffer serious hydrolic pressure that must be overcome with serious clamping pressure possibly damaging or misalligning the workpiece, and you have no real opportunity for a dry fit.

[Wade Lippman]

Cary,

One thing I do with M&T joints (floating or not), is to NOT glue the shoulder area of such a joint since it is end-grain to long-grain. You won't get much strength there

I don't disagree that the tenon will have more strength than the shoulder, but the idea that end-grain to long-grain is a relic of when glues weren't very good. A normal woodworking glue will give a very strong butt joint.

It would be interesting to test it both ways and see how much difference it makes; but until I see some documentation that it doesn't much matter, I will glue my shoulders.

[Mike Henderson]

I don't disagree that the tenon will have more strength than the shoulder, but the idea that end-grain to long-grain is a relic of when glues weren't very good. A normal woodworking glue will give a very strong butt joint.
I've tried some end grain to face grain butt joints and they did not hold very well. When I would tap on the piece it would come loose. This is with Titebond I and Titebond III glue.

I also tried priming the end grain by putting glue on it first and letting it mostly dry (this was to see if the end grain was sucking all the glue away from the joint). That joint failed the same way and just as easily.

If you a way of making end good end grain to face grain butt glue joints, please post. Or maybe you're using a different glue.

Mike

[Jim Becker]

Mike, I think that Wade was primarily indicating that he glues the shoulders of the joint, too, in addition to the tenon/mortise combination. Chris had previously stated he does not glue his shoulders. For the record, I glue mine....

[Wade Lippman]

I've tried some end grain to face grain butt joints and they did not hold very well. When I would tap on the piece it would come loose. This is with Titebond I and Titebond III glue.

I also tried priming the end grain by putting glue on it first and letting it mostly dry (this was to see if the end grain was sucking all the glue away from the joint). That joint failed the same way and just as easily.

If you a way of making end good end grain to face grain butt glue joints, please post. Or maybe you're using a different glue.

Mike

4 years ago I made a box to store dog food with holes cut in the lid to take her dishes.
It is made of hard maple, nothing holding it together except glued butt joints. Looks like crap, but it has held up just fine: I almost wish it would break so I could justify making a nicer one. I haven't any idea what glue it was, but suppose it was titebond.

A few years ago I made up some butt joints and then broke them, just to see what would happen. They tore wood out, so they were plenty strong.

Don't know what to tell you; we have obviously had different experiences.

[J. Z. Guest]

For compressed dowels, biscuits, or Dominoes, I'd use one of the yellow glues. They have water in them, which properly expands the dowels etc.

For un-compressed dowels, I use polyurethane glue. Since it doesn't shrink during curing, it will stay tighter. Plus, it isn't as brittle as the yellow glues; has a little give. Yet it clings tenaciously. (as you'll find out if you get it on your fingers)

[J. Z. Guest]

I always use dowels that are .008" undersized relative to the drill bit. At work we custom ordered undersized pins in bulk, I don't know of any retailer who caries them this way.

FWIW - Dowelmax goes the other way. They supply a 9.7 mm drill bit so that regular old 3/8" dowels will have the proper fit.

I'd like to see a pull-apart test on spiral groove vs. fluted dowels. The fluted dowels give more surface area for the glue than the spiral groove ones and seem to be more well-liked by most people I've talked to.

[Mark Rakestraw]

I have had good luck with end grain to face grain glue-ups with regular Titebond. I use pocket screws and glue to put my faceframes together. Sometimes I make a mistake and try to undo a joint after the glue has had more than an hour or so to set up. I remove the pocket screw and break the joint free -- more often than not the end grain of the rail is holding onto the long grain of the stile well enough to pull a chunk of wood off the long-grain rather than just come apart at the joint.
Mark