[OP]
Contributor
I have seen varying opinions on where to use glue when assembling plywood with domino joinery. Some say if using all tight mortises, then the mortises are the only thing needing glue but some say still run a bead of glue all along the plywood length between the mortises. I value the judgment and experience here greatly, do have at it. BTW love my new DF500. Well worth the expense
Tim in Hill Country of Texas
Moderator
I would never not apply glue to the edges of the material being joined...that's where the strength of the joint really comes from. The Dominos/Dowels/Biscuits/Splines add something to the operation, but the glue on the edges of the material is key. I generally do put some glue in the mortises, too, although I sometimes leave that out when using the Dominos purely for alignment, such as for a table top glue-up.
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The most expensive tool is the one you buy "cheaply" and often...
Contributor
I glue the dominos (or biscuits) and mortise walls unless screws are added, in which case just the mortises. Most of my plywood casework is built with prefinished material that won't accept glue, and the joints are plenty strong - in fact so are boxes assembled dry with butt joints and screws. You can get some extra strength by gluing the edges to unfinished faces but I don't consider it necessary. In most situations with joints that are not highly stressed (e.g. built-in cabinets) oversize mortises will be just as strong as the tight ones if well glued.
To be clear, I am talking about carcass joints in plywood. Glue the edges there and you will likely have to clean up the squeeze-out in the corners. For a task like adding thick banding to a plywood edge or gluing plywood parts edge to edge the edge would typically be glued
Last edited by Kevin Jenness; 07-09-2022 at 2:23 PM.
Moderator
Glue the edges and mortises.
Contributor
I always apply glue to the edges of the wood I’m gluing. It certainly adds strength. However, given that Dominos are loose tenons they are very strong themselves. When doing miter joints or butt joints most of the strength comes from the Dominos. When gluing edges (like gluing up a panel) you don’t even need Dominos except for alignment because edge grain to edge grain is extremely strong. I generally only spread glue on the Dominos and board edges not the mortise. I’ve never had a joint let loose but I imagine you’ll get the whole range of advice on this.
Contributor
Tim, as Jim noted, the strength of an edge-to-edge joint comes from the glued sides; a domino reinforcement is not necessary at all. 99% of all my panels are just glued without either biscuits or dominos. The only time one really needs a biscuit or domino is for alignment, and then it is probably better not to use glue in the mortice so as to avoid any swelling from this, which can transfer through to the surface and become apparent when the finish is applied.Originally Posted by tim walker
Dominos are not even needed to strengthen mitre joints. The grain direction is still mainly edge grain, and it has been demonstrated that this is a very strong joint without any further help.
The main use for a domino is as an alternative to a mortice-and-tenon joint, so as when making a frame. Then one glues the mortice and domino, since the joint relies on the domino for strength. It must not move. In al other circumstances, glue in the mortice has no positive advantage.
Regards from Perth
Derek
Contributor
What use case are you doing that miter joints that don't need reinforcment?
Contributor
Long-grain solid wood and plywood miterfolds are two examples that are quite strong and easy to assemble without reinforcement.
Contributor
A recent cabinet for the workshop used veneered MDF. This does not require reinforcement ...
Solid wood dovetailed drawers ...
Boxes in solid wood ...
These are just a few example. As Kevin notes ...
Long-grain solid wood and plywood miterfolds are two examples that are quite strong and easy to assemble without reinforcement.
Regards from Perth
Derek
Contributor
Those boxes are examples where I would add some type of glued spline to the miters. Just my $.02.
Contributor
Kevin, I have made many boxes like these over the years. The pencil box, above, was made 10 years ago, and is used daily ...
Edges created on a shooting board ...
Glued with the aid of tape ...
And the corners are solid. No reinforcing needed.
What one can do, if the wood/material is a sponge for glue (such as the MDF cabinet in my first post), is first "size" the joint surfaces.
I think that there is a lot of misinformation about mitred joinery.
This turntable was completely re-built by myself without either biscuits or dominos at the corners. I was confident that the joinery would last (which it has so far) ...
Regards from Perth
Derek
Last edited by Derek Cohen; 07-11-2022 at 4:01 AM.
Contributor
.......... This turntable was completely re-built by myself without either biscuits or dominos at the corners. I was confident that the joinery would last (which it has so far) ...
Regards from Perth
Derek
Ahh, another Thorens man. I knew I liked you. I went through the process with my Thorens TD-166 MKII a couple years ago. The miters are as solid as a rock.
40501522112_eb58f96f60_k.jpg
Sharp solves all manner of problems.
Contributor
Rob, I like you too!
You did a great job. Is that the original arm?
I've had this Thorens TD150 turntable 40 years! I rebuilt it completely several months ago. It is quite a long way from the original, with new suspension, acrylic arm board, damping, acrylic secondary table, modified Rega arm, and running a Supex cartridge. Vinyl rules
Regards from Perth
Derek
Contributor
Excepting the base, mine is all original from 1982, so 40 years as well. It has a nice Grado cartridge. I haven't used it since 2007 when I moved into my current home. It was exposed to a water leak in storage that spoiled the veneer on the base and caused the MDF to swell. I used Spanish Cedar for the replacement. After I finished the base I fired it up for a few minutes and then returned it to storage. I have over 1000 vinyl LPs that I need to start playing again. One day.....Rob, I like you too!
You did a great job. Is that the original arm?
I've had this Thorens TD150 turntable 40 years! I rebuilt it completely several months ago. It is quite a long way from the original, with new suspension, acrylic arm board, damping, acrylic secondary table, modified Rega arm, and running a Supex cartridge. Vinyl rules
Regards from Perth
Derek
Sharp solves all manner of problems.
Member
For most glue ups I usually apply glue to both edges being glued before assembling. For plywood I always apply glue to both edges of the plywood so the glue sinks into the ply of both pieces before the pieces go together. I may just be fooling myself but I believe I get a much stronger bond between the two pieces due to better glue penetration in the grain... especially on plywood edges.
This also works well for complex glue-ups. If one side of a joint has glue on it and it has to sit a while before being assembled it can form a bit of a skin which will minimize the glue penetration in the dry piece. Two pieces with glue and a skin on them will still bond very well even with the bit of a skin.
I love the glue bottles with the rollers on top for glue up... even though they require much more clean up than just a regular glue bottle.
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