Glue experiments

[Jesse Cloud]

Following up on the discussions of techniques for gluing dominoes, I ran a few experiments.  I was concerned, as many of you are, that the tight fit of the dominoes would create either a starved joint or excessive squeeze out.

My first tests were putting glue only on the tenons.  There was some squeeze out, but minimal.  After clamping the joint seemed quite strong.  Couldn't pull it or pry it apart.  But then I sawed the joint in half across the tenon, and then sawed vertically down the tenon, leaving a quarter of the tenon imbedded in the mortise piece.  My test of the joint strength, admittedly unscientific, was to try to pry the tenon out with an awl.

The results were dramatic.  Most all of the joints with glue only on the tenons failed.  A second test with small amounts of glue on both the tenon and the mortise produced no failures at all.

OK, I was wrong. :  Even with that tight a fit, you still need glue on both sides.  So I'm following the lead of Bill-e and Jerry Work and applying a little to both the hole and the tenon.  Jerry's idea of wiping off any squeezeout when you put in the first half of the tenon sounds wise, too.

As I said, the test was not scientific and was performed under my local conditions, which aren't typical, its very dry here in New Mexico and that could contribute.  I was using titebond original and cypress, which is pretty soft.  Other species might behave differently, but I'm not gonna take the chance.

 

[Dave Rudy]

Thanks for doing that Jesse.  May not be as rigorous as some scientific testing, but the results are sufficiently consistent and predictable that they produced some useful information, backing up what our most experienced colleagues are telling us.

Dave

 

[Dan Clark]

Jesse,

This is nice work!  Thanks.

Dan.

 

[Matthew Schenker]

Jesse,
This is interesting.  Thanks for doing this, and posting your findings.

It gets me wondering.  Do you think the results of this test carry over to edge-to-edge and face-to-face glue ups?  For example, when making table tops, I regularly apply glue to one surface then rub the two surfaces together to spread the glue.  I've read and heard many experts say that this is a fine way to do glue-ups, and I've never had a glue joint fail.  Of course, now I'm thinking about it!

What's your opinion?

Thanks,
Matthew

 

[John Stevens]

Jesse, many thanks for taking the time to do that and share your results here.

Regards,

John

 

[Jesse Cloud]

Jesse,
This is interesting.  Thanks for doing this, and posting your findings.

It gets me wondering.  Do you think the results of this test carry over to edge-to-edge and face-to-face glue ups?  For example, when making table tops, I regularly apply glue to one surface then rub the two surfaces together to spread the glue.  I've read and heard many experts say that this is a fine way to do glue-ups, and I've never had a glue joint fail.  Of course, now I'm thinking about it!

What's your opinion?

Thanks,
Matthew

Matthew,
The big difference with edge jointing is that you can actually see if the glue covered the other surface and smush (how that for a technical term?) it around somemore if need be.  So I would feel comfortable doing that with edge jointing.

By the way, for what its worth, I got the Domino test drive CD and viewed it this afternoon.  They only put glue in the mortises!

I suspect that when it comes down to it, most methods will work fine, but I'm gonna put glue on both surfaces anyhow.