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Kevin McMichael
05-31-2013, 10:43 PM
I am building a large tool chest out of cypress. I bought some very rough shorts for the project and have started to plane the boards for glue up. Would it be practicle to tongue and groove the boards and glue them up? I have never heard of anyone gluing a tongue and grove joint...why not? It would give more gluing surface.

Derek Cohen
05-31-2013, 11:11 PM
Hi Kevin

There is no reason I am aware of that says you cannot do as you plan - although I do not see a reason to do so in the first place, unless you are thinking that the t&G will act like biscuits to keep the edges flush when joined. Be aware, however, that you do need to joint each board first simply because the edges still need to be joined - and the edges of the boards formed are referenced from the jointed edge. The whole idea of a T&G joints is that it is designed for movement, and not to be glued.

I once (about a dozen or more years ago) made a sideboard top this way. But since then have only used this method to float a butt-joined panel, such as ...

http://www.inthewoodshop.com/Furniture/TheCompletedChests.html

http://www.inthewoodshop.com/Furniture/TheCompletedChests_html_3327bd03.jpg


Regards from Perth

Derek

Chris Hachet
05-31-2013, 11:56 PM
I am building a large tool chest out of cypress. I bought some very rough shorts for the project and have started to plane the boards for glue up. Would it be practicle to tongue and groove the boards and glue them up? I have never heard of anyone gluing a tongue and grove joint...why not? It would give more gluing surface.

It is probably overkill to do this... I have four teenage children living in my house and my kitchen and family room furniture sees amazingly hard use...I have yet to have something come unglued.

I have glued up panels with plain butt type joints for work shelves...If a four hundred pound refrigeration compressor or the short block to a small block Chevrolet bee eight does not kill a butt style glue joint , I am not sure what will.

Chris Hachet
05-31-2013, 11:58 PM
Oh, and nice score on the cypress!

Stanley Covington
06-01-2013, 1:03 AM
In response to your question "I have never heard of anyone gluing a tongue and grove joint...why not?:"

I understand you reasoning. I suspect most woodworkers have had the exact same thought at some time. I know I tried it once.

Here's the reason: Literally thousands of years of history, and lots of modern academic and industry studies, have shown that two seasoned and stable boards properly jointed, edge glued, and clamped, have more strength than the wood fibers themselves. This means that, in most cases, a board made from two properly edge-glued boards will be stronger than a single board of the same width. Modern glues have nothing to do with this.

"Properly" is the critical qualifier.

A T&G joint adds a discontinuity in the glue line that can actually weaken the joint. And a T&G joint is much more difficult to fabricate to the level of precision necessary to develop the same psi strength in the glueline as can be achieved with less effort and material using the ordinary edge-glued joint.

But materials science aside, if you like T&G joints, have fun. Just remember that the T&G joint's advantage lies in its ability to assemble long boards edge to edge while allowing for expansion/contraction, and controlling warping, all while keeping out dust and bugs. A wonderful joint indeed. But glue does not improve it in its classical role.

Stan

Lonnie Gallaher
06-01-2013, 1:59 AM
I have a mid-twentieth century maple chest of drawers that was made by a high end factory that all of the case and drawer fronts have T&G joints. I do not remember the maker, but the maker's furniture does have a collector following.

BTW, the glue joints in the top are starting to fail.

Jim Koepke
06-01-2013, 3:18 AM
That makes me the odd man out. I have glued T&G joints.

Maybe it was just because I was having fun with the match cutter on a Stanley 45.

Mostly my use has been on long boards for large projects.

jtk

Stanley Covington
06-01-2013, 6:49 AM
That makes me the odd man out. I have glued T&G joints.

Maybe it was just because I was having fun with the match cutter on a Stanley 45.

Mostly my use has been on long boards for large projects.

jtk

What were the long boards used for?

Stan

Jim Koepke
06-01-2013, 10:04 AM
What were the long boards used for?

Stan

Book shelves and a storage locker.

jtk

Frank Drew
06-01-2013, 11:40 AM
If the ends of the glued-up panels will show, I think a simple butt joint looks better than even a perfectly fitted tongue and groove joint; strictly personal taste, I know.

jamie shard
06-01-2013, 11:47 AM
In response to your question "I have never heard of anyone gluing a tongue and grove joint...why not?:"

I understand you reasoning. I suspect most woodworkers have had the exact same thought at some time. I know I tried it once.

Here's the reason: Literally thousands of years of history, and lots of modern academic and industry studies, have shown that two seasoned and stable boards properly jointed, edge glued, and clamped, have more strength than the wood fibers themselves. This means that, in most cases, a board made from two properly edge-glued boards will be stronger than a single board of the same width. Modern glues have nothing to do with this.

"Properly" is the critical qualifier.

A T&G joint adds a discontinuity in the glue line that can actually weaken the joint. And a T&G joint is much more difficult to fabricate to the level of precision necessary to develop the same psi strength in the glueline as can be achieved with less effort and material using the ordinary edge-glued joint.

But materials science aside, if you like T&G joints, have fun. Just remember that the T&G joint's advantage lies in its ability to assemble long boards edge to edge while allowing for expansion/contraction, and controlling warping, all while keeping out dust and bugs. A wonderful joint indeed. But glue does not improve it in its classical role.

Stan

+1 Great reply Stan!

Don Dorn
06-01-2013, 1:36 PM
If the ends of the glued-up panels will show, I think a simple butt joint looks better than even a perfectly fitted tongue and groove joint; strictly personal taste, I know.

Agreed. That is the only reason I don't use the T&G. On larger glue ups, I used to use biscuits just for the sake of alignment, but even that prevents me from "rubbing" them together to create the suction that I believe is necessary for proper edge gluing.

lowell holmes
06-02-2013, 10:50 AM
What's neat about this hobby is that you can make the joint you want to. If you want t&g joints, do it.

I would make it a simple glue joint.

I don't use biscuits either. I have large jar full of biscuits and a biscuit jointer I never use.

A few grains of sharp sand in the glue joint will keep it aligned while clamping.

Chris Fournier
06-02-2013, 2:54 PM
No real need so I'd avoid the trouble and lavish joinery on another detail in the project.

Stanley Covington
06-02-2013, 9:20 PM
A few grains of sharp sand in the glue joint will keep it aligned while clamping.

Now that's one I haven't heard before. I suppose it would work brilliantly, but does the sand in the glue line cause problems with plane and planer blades, or do you use a surface sander after glue-up?

Thanks,

Stan

lowell holmes
06-03-2013, 9:58 AM
Now that's one I haven't heard before. I suppose it would work brilliantly, but does the sand in the glue line cause problems with plane and planer blades, or do you use a surface sander after glue-up?

Thanks,

Stan

You only put 6 or 8 grains in the glue joint. It never is seen and unless you cut on the glue line, it will not hit your saw blade. It's a trick that has been around for years. Sharp sand is required.

There was a string about a year ago that dealt with this.

Chris Griggs
06-03-2013, 10:03 AM
Sharp sand is required.

..and what is your preferred method for sharpening your sand? :D


Okay, seriously though, now that I think about it, I would have no idea what kind of sand constitutes sharp sand or how course of sand one would get. This seems like such an odd question, but can you elaborate what kind of sand you use? Is it just the stuff that you get at the BORG in the winter or is it something else?

Derek Cohen
06-03-2013, 10:15 AM
I am not sure why one would want to prevent slippage when glueing up. This aids getting the boards aligned. Once they are clamped firmly, there is no slipping.

I, too, would be wary of sand getting into plane blades.

If you need to prevent movement, an alternative to a biscuit is to pound in a few nails into the centre of the side edge along its length, then clip off the heads. Now attach the next board. The nails will act like a biscuit.

Regards from Perth

Derek

lowell holmes
06-03-2013, 2:04 PM
I use clamping cauls in panel glue up because the boards can move around during the clamping process. I agree the panels don't slip after clamping.

The other string here in the Creek also talks about using a few grains of sugar.

I don't see the difference of 6 or 8 grains of sand is much different from nailing brads in the joint prior to clamping. I'm not talking about copious amounts of sand in the joint.

Jim Koepke
06-03-2013, 2:04 PM
There are many types of sand.

A lot of sand is rounded over from years to eons of getting hit by sea surf.

Sharp sand is often also sold as coarse sand. This is sometime available at larger landscaping supply dealers.

The folks at the borgs seem to have not a clue about sand. There expertise seems to be in when their next break or pay check is coming.

jtk

Jim Neeley
06-03-2013, 8:21 PM
If you need to prevent movement, an alternative to a biscuit is to pound in a few nails into the centre of the side edge along its length, then clip off the heads. Now attach the next board. The nails will act like a biscuit.

Regards from Perth

Derek

This is the technique traditionally sed in bowling alley assembly, or at least has been on the two sets of lanes I've seen pulled out due to wear and replaced. The main body of the lane was grabbed by the demo contractor but i was able to pick up a couple of pieces ~42" square where the pins landed. Thirty year dried bowling alley... it made a heckuva "beat-on" bench.

lowell holmes
06-04-2013, 1:09 PM
Sand blasting sand is sharp sand. Beach sand is not sharp sand, there is a lot of trash and dirt in it.