[Ron_J]

Thanks for that tip. Need to end glue a 3/4" x 4" x 8" oak board to make a 70" board 78" for a side panel. Plan to place this extended board in the middle of the panel so it has support on both sides.

Because it will be an end joint would it be necessary to rabbet the ends of both boards in this situation and glue them together? Thinking a biscuit in the joint may be all that is needed.

If it were me (disclaimer, because I haven't eaten near the sawdust that most of these guys have), I would just stagger any end grain joints and glue it up. I like to use biscuits, but feel they are mainly for alignment purposes, not necessarily for strength.

 

[DrRobert]

Dr. Robert, and anyone can answer - The PVA glue comment peaked my interest so had to look it up. If most white wood glue is PVA, what accounts for the various advertised holding bond? Surely Titebond 3 holds better than the Elmer's Glue school kids use.

Any comments on Titebond 1 (original), 2, and 3? Seems the newer stuff is more expensive. Are they really worth it?

The PVA glues all work about the same. There is a tendency to think white glue is weaker, but that's not true. I believe TB orginal is an aliphatic resin, TBII and white glues are PVA. White glue dries clear, so it is good to use with light colored wood. I've glued up lots of drawers with Elmers Glue All. It holds just as well as yellow glue!

TBIII is another animal completely. I think its a proprietary formula, but I know it isn't a PVA glue. I don't think it holds any better than a PVA. The main reason I use TBIII is the longer open time, so especially in the summer, I'm using it for panel glue ups.



Bottom line they all work about the same. I mainly use TBII.


Another thing to understand is whether a glue dries to a flexible or stiff line. This can be a consideration, for example when veneering or laminating for curves. Epoxy, urea resin and hide glues are rigid. PVA's, TB and TBIII will not.

While using a biscuit would be much easier, the rabbet I planned to use to join the 4" wide boards would be 3/8" D x 3" L. With those dimensions is it still called a rabbet or something else? My guess is three inches of long grain wood glued together with a PVA glue will hold, especially if that board is used to make up a panel with full length boards glued to it on either side.

Its not really a rabbet because its not accepting the end of a board. But I would call it a half lap. Yes it will hold quite well.

If PVA glue does not hold end joints well, will clear Gorilla (non-foaming) Glue be advised? If so, any drawback to using Gorilla Glue for the entire project?

The issue with end grain gluing has more to do with the wood than the glue. End grain tends to suck the glue up resulting in a starved joint. But not only that, there isn't a good substrate, or mating surface, such as long grain to long grain. Think of a board as a bunch of straws. The strongest joint will be long grain to long grain.

I have zero experience with urethane glues and I don't think they aren't commonly used in ww'ing. Far as I know they are not water based, there are issues with glue residue and quite messy deal with.

I agree with the saying you alluded to - There is never time to do a job right the first time but there is always time to do it over again. That is why I am here asking questions of woodworkers who know more than I do.

Titebond has quite a bit of info on their website comparing glues I recommend you take a look.

IMO good old TB original will take care of most any gluing.

 

[Pineknot_86]

there are many examples of glue joints being stronger than the wood itself.
this is totally your call - let us know how it holds up in 5 years or so.

John, I'm at the place where I don't buy green bananas. Woodturners dry wood at the rate of one inch per year. Might not live long enough to turn a piece. Back on topic- I worked for a custom cabinet shop. It is surprising that glue joints will be stronger than the wood itself.

 

[Larry42]

End grain joinery (solid wood) is a lot less than ideal. Very simple solutions: dovetails or box joints.
The 8" part glued between two full length parts is just fine W/O and end grain joinery. The hard part is keeping the 8" part tight to it's mating piece while the glue is slippery. Put some paper down on your bench. Clamp a long piece to the bench, over the paper with glue already on it. position the rest of the parts (with glue) and snug the clamps. With a waste block fastened to the bench to work against, tap a wedge in to push the 8" piece tight. The glue will seize within a very short time (2 minuets or less) & you can continue your clamping up off the bench so you can have alternate pipe clamps on both sides of the panel. Be sure the clamps don't touch the wet glue or they will stain the oak black.
An alternate method would be to use a long clamp to pull the 8" part tightly into it's place. If you don't have a long enough clamp use two hooked together. Not a lot of force is needed. Pre-stretching the center board with biscuits or Dominos would also work.

 

[spectaculartrim]

Old post but here’s another option. Production cabinetmakers also assemble using pocket screws especially where the screws won’t be visible after install. The pocket holes are made in the cabinet sides and the screws pierce the face of the plywood on the backs as well as the long grain of the face frames (if used. This is superior to driving screws through a back into the edge of a piece of ply or melamine or mdf.

 

[holtzdreher]

Several years ago, I made up a small outdoor cabinet to hold a fence charger. Just for giggles, I used glue and pegs for everything but the hinges and shingle roof. It was made from scrap plywood from a nearby factory. I don't know what they make, but I left have left things made out of that plywood out in the weather for years and it didn't rot or come apart. Probably radio active or something.

 

[Rebelwork]

This is going to depend on how far the builder is willing to go to not use fasteners,,

 

[Steve Neul]

Building two cabinets with doors and adjustable shelves using 3/4" oak panels I will glue up. One is 78" H x 30" W x 12" D, the other is 42" H x 26" W x 12" D.
I know how to glue up the panels but, if gluing is so strong, is it advisable to glue the entire cabinet together without any fasteners?

Can make dados and rabbits where needed but will just using glue work? Can use biscuits or dowels but have heard, as far as gluing panels is concerned, that just glue is as strong as either biscuits or dowels.

Anyone try this? What has your experience been?

Mainly fasteners are to expedite the assembly process. There is no reason cabinets couldn't be assembled without fasteners if you wish.

 

[Jim Frye]

I assemble carcasses with biscuits and bamboo pins, but aren't those also fasteners of a sort?

 

[B Coll]

When you build the case, how do you avoid end grain joints? Biscuits? Dowels? Dovetails in the casework?

When I do an end grain joint, such as a rail into a stile of a face frame, I simply do it mortise and tenon. You could do loose tenons, or even stub tenons. Dowels have very little glue surface and are not a good choice in my opinion. If you want to do a butt joint make sure you size the end grain before glue up. If not, the end grain will wick up the glue.

 

[BigCountry79]

Yes

 

[DrRobert]

If you want to do a butt joint make sure you size the end grain before glue up. If not, the end grain will wick up the glue.

I could be mistaken but I think Patrick Sullivan proved this isnt a factor, didn’t he?

But like you, even after then”expose” I still size end grain. After watching his experiment, and all the debate that swirled around it, I still don’t believe a butt joint is that strong. Cosman, Spagnolo, and Stumpy Nubs probably did the best review jobs.

If you haven’t seen Mr. Sullivan’s expose on glue joints, it’s worth a watch. He’s also got some intereresting jig ideas on his channel.

 

[woodnthings]

Mainly fasteners are to expedite the assembly process. There is no reason cabinets couldn't be assembled without fasteners if you wish.

Right on! The fasteners hold the piece in place until the glues sets and reaches maximum strength.
The back set into a rabbet adds tremendous strength against racking.
Dados on the sides adds strength to prevent the shelves form collapsing from over loads.

 

[Tony B]

You wil never convince me that end grain or plywood in a Dado will be as strong with 'glue only' than with both glue and fasteners.
Maybe, I am reading this wrong.

 

[Rebelwork]

When I do an end grain joint, such as a rail into a stile of a face frame, I simply do it mortise and tenon. You could do loose tenons, or even stub tenons. Dowels have very little glue surface and are not a good choice in my opinion. If you want to do a butt joint make sure you size the end grain before glue up. If not, the end grain will wick up the glue.

K
On cabinetry you can do end grain to edge on a face frame without a problem using a Senclamp, pocket screws,M&T,pocket screws, etc..

When I started we doweled all face frames.. Ive got a Senclamp, but only use it to draw plywood together for bar backs or large tables.

 

[woodnthings]

You wil never convince me that end grain or plywood in a Dado will be as strong with 'glue only' than with both glue and fasteners.
Maybe, I am reading this wrong.

When I use a dado, I always use glue as well. It is a structural joint, not a mere adhesive and fastener joint. It can't separate unless the side panels come apart and drop the shelf. By using a rabbet on the back and gluing that in as I do, the sides won't come apart.
There is a lot of controversy about end grain joining with glue.
Various tests have given conflicting information regarding the strength of those joints. I.E. Mathias Wandell, Patrick Sullivan, on You Tube.
Plywood is different than solid wood because some of the plys are actually long grain.

 

[DrRobert]

When I use a dado, I always use glue as well. It is a structural joint, not a mere adhesive and fastener joint. It can't separate unless the side panels come apart and drop the shelf. By using a rabbet on the back and gluing that in as I do, the sides won't come apart.

A dado is by definition a housing, not a structural joint, depending on depth, at some point a dado becomes a mortise. I would guess that’s a depth about 2/3 the thickness. Furniture is different than cabinets, but it’s till the same principle.

That said, a bookcase or cabinet box mounted to a wall you can get away with it in sheet goods, but maybe not solid wood. And, of course it depends on the depth. A shallow dado is typically done for cabinets, only for alignment, it’s still screwed together.

So, no, I agree not much will go wrong with a your 12” deep plywood book case, 1/4” deep dados & glued. Not so with an 18-20” deep desk or dresser. And especially solid wood. If a side moves or cups, thats a lot of stress on a shallow dado joint that even glued is 100% end grain. Of course nowadays that’s the stongest joint there is, right? 😳😳This is why partial depth dovetails are a typical treatment to keep that sides tight to the shelf or divider.

WADR to Mr Sullivan and Wandel, their experiments have merit, but cabinet doors and furniture are never going to be built with butt joints!

 

[Steve Neul]

Dado's do a lot to aide the structure of a cabinet. It increases the surface area of the joint for the adhesives. Then for shelves the dado takes the vertical weight leaving the adhesive to only have to hold the joint together.

 

[woodnthings]

A dado is by definition a housing, not a structural joint, depending on depth, at some point a dado becomes a mortise. I would guess that’s a depth about 2/3 the thickness.

Of course it is a structural joint. Where did you get your definition? Here's one I found:
I have never considered a dado a "mortise" which captures the tenon on all 4 sides rather than just two.

What Is A Dado Joint - Rockler

Dado joints are easy to make. They are the strongest woodworking joint and are often used to build cabinets & bookshelves.

www.rockler.com

A shelf in a dado can't move because it's captured on the top and the bottom unlike a simple butt joint that's just nailed or glued and relying on the fasteners alone or the glue to secure it.
A shelf glued in a dado is one of the strongest joints in woodworking as stated in the Rockler link.
I used dados to secure the steps/treads on my library ladder which needs to support my 200+ lbs.
I would never consider making a ladder without dados and glued in treads. Look at wood step ladders, they use the same method.

 

[DrRobert]

Dado the strongest joint? . Mortise/tenon, dovetails, wedged thru tenons are many times stronger.

Dados are excellent for supporting a vertical weight load. Glue holds it together, and I agree most all the time that’s all you need.

A dado cannot hold a bowed side.