Really big clamps?

[Shrug53]

Ok, here is the situation: I nee a wall 5x10 whic is nearly impossible to find as one sheet of plywood. So I am going to join several sheets of plywood, probably with biscuits or dowel joins. I want to make sure there is also a good bead of glue down, but am not sure how to clamp them together. I can not seem to find 5' long bar clamps. Is there another way?

Thanks!

[Turtle49]

There were a couple of idea's that came out in this thread.

Or I did find clamps at lowes that fit on the ends of 3/4" pipe. All you have to do is get long pipe.

Hope this helps.

[shil]

My trailer's 5 x 10, my side walls are 4 x 10. I glued up a 4 x 11 blank before cutting things to size with the template.

I used the trailer frame as a work surface. I positioned the 4 x 8 so that the 4 x 3 would overhang the edge of the frame just enough, and clamped the 4 x 8 to the frame with C clamps so that it wouldn't budge. After gluing everything up I used bar clamps to draw things together, with one end of the clamp on the edge of the 4 x 3 and the other hooked over a frame rail.

I used exterior carpenter's wood glue, with dowels to line things up. After it all set up, the glue joint by itself was strong enough that I could pick up the wall and move it around. I added an interior butt block, just for fun; that's where I put the galley partition.

Worked for me...

[Turtle49]

here is an Example of a spanish windlass.

[R Keller]

Shrug 53:

A "poor man's" scarf joint consisting of a several inch wide rabbet might be a better/stronger way to go for joining the plywood together. Then you can just clamp a board across the joint when gluing.

If you are set on edge-gluing the plywood and using biscuits or dowels though, couldn't you just use some ratcheting straps to clamp? Might be tough to keep the plywood from bowing though. That would be true with really long pipe/bar clamps too.

Rik

[Steve Frederick]

When I glued the sheets for the Stripper, I did a half lap joint, cut with the router and a straight edge. For clamping, I found a really warped 2 by 4 the warp is on the flat(3-5/8")side. Clamp the ends, I screwed them to the bench, with the warp curving down. You should get even pressure across the width of the sheet. You could also shim the 2 by at points along the joint to achieve the same result.
You could cut a slight curve in a board and clamp it with the curve down.

[mexican tear]

Scarfing was how I got my 10' sides too

Seems realy strong.

kai

[R Keller]

Yeah, what Steve F said. A half-lap joint. That was the phrase I was looking for!

I did a scarf joint and glued it similar to what Steve said. A warped 2x4 on-end with another on top, clamped to the table on each side and some shims between the two 2x4s to distribute the force.

Rik

[Chuck Craven]

[quote="Shrug53"]Ok, here is the situation: I nee a wall 5x10 whic is nearly impossible to find as one sheet of plywood.

Shrug53 Where do you live?
Alpine plywood in Milwaukee has 5’ X10’ x ¾” AC exterior fur plywood.
$118.53 a sheet. If you are going with 4x8 sheets use a ¼” slot cutter on each edge and a spline, made of ¼” plywood. Harbor freight has ¼” carbide slot cutters for router use at a good price. Use good 4 or 5 layer plywood for the spline. T-88 glue is a two part slow setting epoxy glue used for aircraft building. That type of joint will be stronger than the plywood it’s self.

Chuck

[Ron Dickey]

Found these site maybe they will help.

NewWoodworker.com - Woodworking Tips, Tricks and Tools! - Using Adhesives

in that they said

Plywood
Just when you start to understand how grain structure interacts with adhesives, along comes plywood to confuse the issue. The alternating grain directions within plywood is what gives it strength, but it also means gluing along any of its edges is not going to produce a strong joint. I treat all plywood as short grain and take appropriate precautions according to the situation.

Edge Joints
http://www.taunton.com/finewoodworking/pages/bw0002.asp

http://woodworking.about.com/b/a/068639.htm

Best diagram I found.

Scarfing plywood sheets - scarfing jig
http://www.oneoceankayaks.com/stitchglu ... rfjig2.htm

Pipe clamps would be best but you could use rope however you would want to have a flat pc of wood across the joint to
assure it will stay flat, I would put wax paper or plastic wrap between that board and the glue

It also said somewhere that doing a dry run first would be wise so as to see it if was all square.

Ron D.

[Larry Messaros]

Ok, here is the situation: I nee a wall 5x10 whic is nearly impossible to find as one sheet of plywood. So I am going to join several sheets of plywood, probably with biscuits or dowel joins. I want to make sure there is also a good bead of glue down, but am not sure how to clamp them together. I can not seem to find 5' long bar clamps. Is there another way?

Thanks!

Shrug, you didn't specify what thickness of plywood you wood be working with. I will assume you are thinking about 3/4".

I don't think trying to use biscuits or dowels would work very well.

My idea is simple, you take 1/4" plywood and lay it out to the size you would need, for example, 1 - 4x8 sheet and 1 - 1x8 piece for the top and a 1x5 piece for the end. Now take the same size pieces and rearrange them to overlap. Then finally for the 3rd layer rearrange those pieces so they overlap. Glue them all together and voila, 1-5x10 sheet of 3/4" plywood.

So to recap, (my wife makes me do this 'cause she says my descriptions are confusing!) build up 3 layers of 1/4" plywood which is overlapped to produce whatever size plywood you need, at probably a fraction of the cost of the larger sizes. Using glue in between the layers and several cement blocks, engine blocks, vehicles, dirt, rocks, group of very patient people, etc to provide weight while the glue dries also takes care of the clamping issues.