Bob Willing

What is the best way to join the edges of plywood? If you were making a box and you did not want the ends of the plywood to show at the joint. Should I dado one of the ends so just the thickness of the outer veneer shows?

phinds

the most common method, I believe, to totally hide the plywood end grain (or any other end grain for that matter) is the miter joint. Check it out here:

http://www.hobbithouseinc.com/person...ineryterms.htm

You may want to reinforce it with biscuits or a spline, all shown at that joinery glossary I just pointed you to.

Paul

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Willie T

I think I'd use a lock miter joint.

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cabinetman

That works good...looks like this:

rrich

You could glue a strip of matching hardwood to the edge of the plywood. Rather than hiding the edge, flaunt it.

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Bob Willing

cabinetman

That is exactly what I had in mind. I tried the lock miter joint on some scrap pieces of plywood and this seems a little damgerous. I did not like the kick back because you are taking so much material all at once. I also had a problem with set-up. Another draw back is you need to attach a piece of wood to support the edge when you make the alternate edge that is when you set the wood pirpendicual to the table. The other idea of putting a matching piece of wood on the end sounds like another good idea.

I think I will try the dado first and i will probably use pocket screws to secure the jount.

Willie T

THIS will give you some tips on how to easily make several passes to avoid the kick-back.

Bob Willing

Those are good videos if you are making short pieces, but I will be working with pieces 36" and 56" long and 16" wide. I suppose it could be done but I would need to build a support system to hold the long boards.

cabinetman

I wouldn't use pocket screws. I would just use glue and clamps. Use a 2" - 3" wide piece of 3/4" (out of anything), by the length of the joint as a clamp scab against the side with the thin edge. That joint can be clamped from two directions and produces a good bond.

lcurrent

A jig like this will edge glue plywood also

http://farm3.static.flickr.com/2534/...0584e1d8_m.jpg

Plus mortise for edge gluing ( Tops ) for tables

All these were cut using this jig

http://farm3.static.flickr.com/2604/...aeec9f9b_m.jpg

Larry

Tony B

This is what I do when the edge will be exposed.
I start with a piece of stock approx 2" Square and as long as needed. I then dado a 3/4" rabit on 2 sides where the plywood can butt up against and also provide a good gluing surface. Then I roundover the outside corner. I then use glue and a pin nailer.
See sketch below

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Gerry KIERNAN

I am making an assumption here that you are doing your boards on a router table. Perhaps it would work better if you clamped the boards down to a bench and used a hand held router with an edge guide to make your lock miter joints. Take small cuts at each pass to reduce the tendency to kick back and also to reduce chipping out or splintering.

Gerry

Bob Willing

This sounds like good idea, but don't forget the router bit is 2" or 50.8mm in diameter. I don't know if the standard plate will accept that big of a bit. I will check it out.

Tony B

I would nix the lock miter idea. It will break.

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nicewood

I would do as Tony B suggests in post 11 above, with one small variation, remove the internal corner of the corner block it will not affect the strength and will add to the internal apperance

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GeorgeC

Good link for a number of different joints.

George

woodnthings

I would use a splined miter like this:
splined edge miter joint --- A joint that is used at the long edges of two planks, as in the side/bottom of a box, and that is mitered, usually at 45 degrees on each plank, and then strengthened by the addition of a spline. Compare/contrast to edge miter joint. Examples:





The only caution is not to use a spline with the long grain running the length since it will have no strength. You should make a cross grain spline so the fibers have to break rather than shear
in failure. If you have to make them in 2 - 8" pieces from wide stock that would be better than long grain. bill

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Bob Willing

Thanks for all of the replies! I went with cabinetmans answer and it turned out great.

dansandsleeds

dont hide it!


it can look great if smoothed over.

heres my recently finished guitar stand with ply!

GeorgeC

Even with "light" passes, lock miters in plywood seem to have a lot of splintering.

George