Using Biscuits in plywood

[Ian Haywood]

Does this work well? I bought a plan for a 12 compartment Martin house online and it's made of 1/2" plywood. It calls for lots of nails (or brads from a brad gun), glue and metal angle brackets to attach the various pieces together. I think for strength I'd like to try using biscuits where I can but don't know how they'd do in plywood. I bought some '0' size yesterday but haven't gotten to the shop yet to see how it would work. I thought they might cause de-lamination since plywood isn't solid.

thanks,
Ian

[Chris Friesen]

Biscuits in plywood work just fine. However, when possible I like registering the biscuit joiner via the base rather than the fence, and with 1/2" material you need to raise the material 1/8" or so to center the slot on the edge.

[Prashun Patel]

I've heard of dowels, pocket screws, rabbets, and dados for edge joining pwood. If dowels work, not sure why biscuits wouldn't. Glue along the edge was always recommended.

For most apps, brads and glue are the easiest for me. I reinforce joints requiring strength with cleats. They're cheap, sturdy, easy to install, and can be made decorative.

[Ian Haywood]

Thanks, I'll try it out when I get the project going.

Ian

[Ian Haywood]

I reinforce joints requiring strength with cleats.

Do you mean 90 deg metal corner brackets? There's a few of those in the plans too.

Ian

[Chuck Tringo]

Norm uses biscuits in plywood all the time, so it must work :D In fact, in this season of New Yankee Workshop, he is building kitchen cabinets and uses biscuits to attach the solid wood face frame to the plywood cabinet. I see no reason why it wouldnt work as well in plywood to plywood applications.

[James Hart]

Ian,

Not sure of the overall construction on this house, but if a martin is half the size of the water chickens (pidgeons) bombing my house I'd be a little concerned.

If the parts you're thinking of biscuiting will be attached on 2 opposite sides you're probably OK. A 0 biscuit into 1/2" plywood isn't much if it's supporting a ledge that the birds will sit on. If the part is housed on 3 sides, you should be fine.

Biscuits are great in plywood, but you have to watch the size of the biscuit and the types of pressure the joint might be subjected. For example, when Norm puts some #20 biscuits between a 3/4" face frame and a cabinet carcass that joint will be subjected to almost no direct pressure trying to pull it apart.

Jim

[Ian Haywood]

This is a picture of the finished house. The floors of each level are a solid piece of plywood with the top and bottom floors are reinforced along the edges with lathe strips. The vertical room dividers on each level and the outside walls are what I am thinking about using the biscuits on. Each level stacks on top of the one below it, so the outside walls are not one piece. That part concerns me as we have a good bit of wind here. The pole is going to be a 3 1/2" square tube (4x4 lumber shown in picture) and it runs through the center of the house top to bottom. That should give it some support from wind shear pressures. I can't post the plans.. copyright and all.

Martins are about the size of Barn Swallows. Weight is about 1.9 oz. The nest is much heavier tho, they like to use mud dams sometimes.

http://i11.photobucket.com/albums/a193/imh_98/banding.jpg

[Chris Padilla]

I'd just dado/groove everything and not mess with biscuits (but yeah, biscuits would work fine). Oh, and paint the living you know what out of everything so it will last outside. If you are concerned with "exposed" plywood edges, just glue some poplar (i.e. cheap) on the edge...and paint the you know what out of everything...oh, wait, I just said that. :)

[Prashun Patel]

Do you mean 90 deg metal corner brackets? There's a few of those in the plans too.


I mean 1x1's or 1x2's screwed or glued into the corner. Angle brackets are good too. Where cleats and brackets will be hidden, they're (IMHO) a sturdier and easier than biscuits and the like.

Ever try pocket screws? Avoids clamping or brad nail hole filling.

[Ian Haywood]

Thanks for all the ideas. I'm still trying to visualize how best to accomplish it. I'll fiddle around and maybe come up with something that won't fall apart with the first breeze. I'm no woodworker, that's for certain.

Ian

[Al Killian]

I built a bookcase for my sis-in-law using ply and biscuits. It has been one year and has survived her little one climbing on it.

[Curt Harms]

My understanding is that biscuits were originally intended for sheet good, i.e. mdf, plywood and such. I've used 'em on plywood cabinetry with no failures to date.

HTH

Curt