# Mortise/Tenon- Glue preference



## Wood Butcher (Jul 28, 2010)

I am building a stool out of ash to go with a carving bench I built last year. I am considering two types of glue to use in the mortise and tenons joining the stretchers to the legs and the legs to the seat platform, Gorilla Glue or Titebond II. The mortises are not "through mortises" and I'm concerned about glue expansion tending to push out the tenons during the glue-drying process, which could be a problem with the Gorilla Glue. I believe it can expand up to four times its original volume. However, I think it would be stronger than the Titebond II. Would using a web clamp around the legs as the glue is drying solve the problem? Would another type of glue work better?


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## mdntrdr (Dec 22, 2009)

As long as the joint is properly sized, any wood glue will be stronger than the wood. I would use TB and a band clamp. :smile:


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## Dvoigt (Dec 6, 2007)

I use TBII for most things. I've never used Gorilla glue but from what I hear it is messier because of how it expands.


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## kjhart0133 (Feb 4, 2009)

Use Titebond, definitely! But if you just gotta use Gorilla glue, you can make a small expansion hole or two in the bottom of the mortise and/or fashion some grooves in the tenon. These will provide space for the glue to expand into.

Kevin H.


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## firemedic (Dec 26, 2010)

Couple years back (when gorrila glue came out) I thought it was the greatest thing since slided bread and used it for everything I could think of... Even called tech and got specs on thinning it. I did so with MEK and used it as a sealer and varnish! 

The more you thin it the less it foams. So by thinning it, it won't push as much foam out of the cracks... Also makes it weaker though.

That all being said... Go with TB2, it's a much better glue especialy for MT joints. Every MT I've done with GG has resulted in some work with a razor knife and sandpaper. It simply can't be glued properly without foam out.

Only time I ever use GG anymore is for exterior rough construction... Glueing headers together etc...

Take care!

~tom


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## Tony B (Jul 30, 2008)

*I use TB II for just about everything.*

As long as your M&T joint is snug it should last about 100 years or so.


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## TGRANT (Jan 25, 2011)

Tony B said:


> As long as your M&T joint is snug it should last about 100 years or so.


Can't agree more. 

Ultimately the strength of the M&T joint is more dependant on the tightness of the fit rather than the glue. Opinions vary, but at dry fit a well cut M&T should be pressed in by hand (without a great deal of whacking with a blunt instrument) but not drop apart when subjected to gravity – gentle pulling will be needed to dissemble the dry joint. If you get that kind of fit, a typical wood glue like Titebond should hold the joint together longer than you’ll be around.


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## 1066vik (Feb 18, 2011)

I use gorilla glue for outdoor applications and TB II for indoor.
Titebond will start to set much faster than gorilla, cleanup is easier, and it won't stain your hands brown.
It also washes out with soap and water if you start cleaning before it dries.
Once gorilla glue is on a pair of pants, it's there forever.


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## Tony B (Jul 30, 2008)

*What if M&T joint is too loose?*

There are two things you can do...cry and fall to pieces or fix it.
Just cut some veneer slices of the same wood on the table saw. Apply glue to one cheek of the tenon, lay a veneer slice on it and immediately put glue on the veneer and and also on the other side of the tenon cheek and then insert into the mortise. 
Of course, always do a dry fit first.


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## woodnthings (Jan 24, 2009)

*You need an expansion slot or chamber*

You said......"The mortises are not "through mortises" and I'm concerned about glue expansion tending to push out the tenons during the glue-drying process, which could be a problem with the Gorilla Glue."....
You are correct, without a slot or a deeper mortise than the tenon, the hydraulic pressure from the glue will keep the joint from closing up tight. Use the glue sparingly, and coat/brush both surfaces lightly. :thumbsup: bill


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## Wood Butcher (Jul 28, 2010)

*Thanks Guys!*

I'll be using the Titebond II. The tenons are VERY tight in the hand-chiseled mortises. Therefore, I plan to make verticle grooves in the tenons to ensure that in fitting them together (after applying glue to the tenons) that some glue remains on the sides of the tenons. Appreciate your input! Bob


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## firemedic (Dec 26, 2010)

Wood Butcher said:


> I'll be using the Titebond II. The tenons are VERY tight in the hand-chiseled mortises. Therefore, I plan to make verticle grooves in the tenons to ensure that in fitting them together (after applying glue to the tenons) that some glue remains on the sides of the tenons. Appreciate your input! Bob


:thumbsup::thumbsup::thumbsup:

Just keep in mind the fit for a glue joint should be just tight enough to not squeeze all your glue out, but also not so lose that glue is filling a gap. 

I'm sure you already know that, just a friendly reminder... glues strength is in binging long grain to long grain and lacks any inherent strength of it's own... so you might consider cleaning up the tenons a bit as appose to trying to give 'em teeth... 

PICTURES PICTURES PICTURES! Please keep us up to date on how the project goes... I'll probably learn a thing or two from your design!


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## Tony B (Jul 30, 2008)

Wood Butcher said:


> I'll be using the Titebond II. The tenons are VERY tight in the hand-chiseled mortises. Therefore, I plan to make verticle grooves in the tenons to ensure that in fitting them together (after applying glue to the tenons) that some glue remains on the sides of the tenons. Appreciate your input! Bob


M & T joints should not be any tighter or looser whether they are hand cut or machine cut. If they are VERY tight you might want to use a light sanding/chiseling/planing on either the M or the T. Cutting grooves to relieve air pressure and glue pressure will work for that but on the other hand, you are reducing the effective glue surface.


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## JerryO (Jul 26, 2010)

Wood magazine published a glue test some time ago. The titebond won hands down. They glued up just about any joint you can think of and subjected the joints to a machine that put pressure on the joints. The gorilla and hide glues lost. The tb 3 is also rated for outdoor use as i the gorilla glue. 
Having used the gorilla glue you need to wear gloves. If you get any on you your hand turns black where it landed.


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## rrich (Jun 24, 2009)

I vote for any of the TiteBond series. A snug fitting mortise and tenon joint become a single piece of wood with any TiteBond. (Not really but it seems that way.)


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## redslider (Jul 8, 2013)

TBII (or one of its varieties) works well for ordinary M&T and gives a good bond, easy to work with and clean-up. For rougher or softer woods where there are gaps or shreds, I prefer to use TB Trim & Molding glue. Just as strong, but thicker and fills in gaps and irregularities nicely. When working with soft woods I prefer to chisel rough and leave some fiber and shredding on the sides of the mortise. TB trim glue will surround these fibers and make an even stronger bond. For outdoors or joints I expect to take a lot of stress and punishment, my preference is to switch to an epoxy like PC7. Harder/messier to work with, but offers strength and resistance to extremes that can't be matched by ordinary wood glues.


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