# Can I use biscuits to join BC plywood?



## opalko (Feb 2, 2010)

I am making a set of recycling bin shelves for my garage out of 2×4's and 19/32" BC plywood. The frame is the 2×4 material and the shelves that the bins sit on are the plywood. Doing this in a hurry and I screwed up and made the shelves too narrow…..aaarrrrghhh! Actually what happened was I made them wide and had plenty of room but when I set it in the garage it took up too much space, so I thought.. "I'll just knock 6" off and it will be fine."..it wasn't.

My question is: since I still have the cutoffs from the original way I built it, can I join the cut-offs to the too-short shelf with biscuits? I've only used biscuits with real wood, and perhaps good quality plywood. You know what home center BC sanded ply is like. The kicker here is that the shelves (will be 20"x24" with the added in 6") will have to support the weight of a full bin..like a big thing of newspapers etc. Or am I stuck buying another sheet of plywood to start over? To get an idea of what I'm making, look at this photo:

Garage shelves that are sort of like what I'm building...picture these only wide enough for just one bin stacked 4 high


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## CueballRosendaul (Jul 16, 2012)

Use a long tenon instead. Cut a 1/4" slot in the edges of the shelf and the pieces you cut off. Make the slot about 1/2" deep, then cut a tenon out of hardwood just a tad under 1" to fit in the slot. I think you'll be sorry with biscuits in a butt joint on plywood.

You can make the slots with two passes through the saw blade, just flip the piece around on the second pass so you're sure the slot will be in the middle of the edge. Make the slots first and cut the tenons to fit the slot. Once you get one right, the rest of them will go fast.

Another option is to add a face frame piece as a cleat to the bottom of each front edge to give it some support, in which case you may be able to use the biscuit joiner. Beware that biscuits swell up and could blow some bulges in the surface of the plywood.


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## MikeThrockmorton (Nov 4, 2013)

I've done it when cobbling scrap ply together to make a mockup.

If I had to do it again, I'd do it with splines. Less effort to be accurate, arguably stronger.

Edit: yeah, what Matt said.


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## cutmantom (Feb 2, 2010)

It will work, might not have the maximum strength though, could add some pocket screws


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## rwe2156 (May 7, 2014)

Not gonna work, dude. Your edge joining plywood which is about the weakest joint there is and not only that, its got to be weight bearing.

You can use the cutoffs but will have to scab on a wide piece of plywood or 1X material underneath to span the joint.

Like Cueball said, you could go with 1×2's on edge front and back but you don't need biscuits just glue and screw them. This is probably the best solution.

Or, you could use full width 1X4's laid flat front and back edge screw plywood from the top.


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## opalko (Feb 2, 2010)

I can't change the thickness of the ply by adding anything underneath or on the front edge as the 2×4 part is already built for an exact fit between the ply shelves.


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## exelectrician (Oct 3, 2011)

...or you could join the 6" strip back on with biscuits and then have the join at the back where the stress is low …..


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## opalko (Feb 2, 2010)

I won't have enough material with the added 6" to rotate the shelf to make the join at the back.


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## opalko (Feb 2, 2010)

Thanks for all the replies so far!


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