How to bend plywood??

[micklen]

Hi,
Got a bunch of sheets of 10 mm birch plywood laying around in my garage.
Planning to build a new bunker bed for my son.
I would like to make to corners around the bed round [30 cm radius], so I  wonder if anyone got any good ideas how to do this?

Maybe there is a  skilled boat builder in the forum, that maybe could share some experience?
??? ??? ??? ??? ??? ???

//carl

 

[danjames]

A quick method is to cut kerfs into the plywood, nearly full thickness, do a test to see how close together you will need to have the kerfs, bend the plywood to desired shape then fill all of the kerfs with thickened epoxy, this will make it keep its shape.

You could also use bendy ply for the curves, this is plywood with all veneers running in the same direction, it bends quite well, but would be a different type of ply than what you have.

Dan.

 

[micklen]

How about steam bending 10mm ply.. .anyone tried that?

//Carl

 

[danjames]

Not tried it, but I don't think it would work because of the different grain directions in plywood.

Dan.

 

[BSHuff]

How many ply is your wood. If it is only a few plys and not like 8 ply Baltic birch or the like,  you can plane off one or two of the plys and then laminate 2 sheets of the planed down stock over a form. The grain direction is important to do this.

Ply is hard to bend by design. To bend it the stress against the plys is counter design.  Take a pad of paper or a stack of cards and bend it over,  all of the plys would need to move to bend,  then imagine each sheet of paper covered in glue

 

[L.J]

A quick method is to cut kerfs into the plywood, nearly full thickness, do a test to see how close together you will need to have the kerfs, bend the plywood to desired shape then fill all of the kerfs with thickened epoxy, this will make it keep its shape.

You could also use bendy ply for the curves, this is plywood with all veneers running in the same direction, it bends quite well, but would be a different type of ply than what you have.

Dan.

This is probably the quickest and most efficient way to do it.

 

[galwaydude18@gmail.com]

Ya flexi ply is the job. You can get it in long grain and short grain and bends like a hot knife in butter.

 

[mouppe]

I used two layers of 3/8" bending ply with a sheet of veneer on either side. You have to build the form first.

I made a video on how I did it here.

You can use plenty of clamps instead of a vacuum press.

 

[Guilliaume woodworks]

The ply I've been getting lately is already bent!  Next thread should be " how to straighten plywood".  [big grin]

 

[upscale]

How about steam bending 10mm ply.. .anyone tried that?

The problem with steam bending plywood is getting your entire piece into a steam tube so you can heat it up. And, that's aside from the fact that general plywood structure is layered and cross grained to give it strength.

As others have mentioned, you're probably better going with bendy, wigglewood, type of ply where all the wood grain runs in the same direction.

 

[builderbob]

The ply I've been getting lately is already bent!  Next thread should be " how to straighten plywood".  [big grin]

Hahahaha ain't that the truth!

 

[Vi_k]

Snake Ply is the move. Comes in 4x8 sheets, different thicknesses and you can get the grain long or short. Quarter inch stuff works nicely if you aren't used to handling it. Kerfing or steaming a piece of plywood will not do as nice of a job.

Good luck with your build,

Vi_k

 

[jmbfestool]

10mm is far to thick to bend you would need to thickness the plywood down to 4mm or less to make it bendable and then laminate it to create a solid curve. 

If you have a thicknesser and you don't want to buy more plywood you can thickness you're plywood down.

Easiest option would be to buy flexi ply or some thin plywood.

 

[scotternst]

Kerfcore ( http://www.kerfkore.com/products.html ) is a great product for what you want to do. It is basically the same thing as kerfing your own ply, but it is really consistent. It comes in different skins (from masonite to poplar) and different thicknesses. You can glue two pieces with the kerfs inside  and you get a really stiff radius when it all setts up. Great product and it has a much nicer surface than Bender Board.

 

[jeyanmezza324]

i was wondering how i can bend plywood too. is there any proper way how to do that

 

[avrs22]

cutting slots in the back of the ply is how they do it around here. wetting the veneer can help the veneer from not breaking if its a sharp turned.
like in this youtube

 

[JoggleStick]

A quick method is to cut kerfs into the plywood, nearly full thickness, do a test to see how close together you will need to have the kerfs, bend the plywood to desired shape then fill all of the kerfs with thickened epoxy, this will make it keep its shape.

You could also use bendy ply for the curves, this is plywood with all veneers running in the same direction, it bends quite well, but would be a different type of ply than what you have.

Dan.

There really isn't any more to say than this first response. The thread should have been locked after that because I'm sorry fellas, but some of the other suggestions being made are just silly.
Whoever said to steam bend this plywood has clearly 'no clue'.
If you want to maintain a smooth line, scarf join the ply panels together and you'll maintain a seamless line/plane.  8:1 scarf is adequate, but 10:1 will give a smother transition. This is for edge/edge and end/end joins. You can of course use butt plates/straps..., depends how professional you want the finished article to look.