Steam forming ply

[Frederick]

Hi,

I hope I am in the correct place.
I am currently building a box in the shape of a treasure chest for my Granddaughter. The size is 10" x 6" x 6". The lid is to be formed into a slow "S" shape running from front to rear. The purpose is to support 10 x 1" thin strips of steam treated and formed wood.
I ask if 3.6mm ply could be steam treated and formed or would it be best to try and find another way. I think I may be asking too much of the ply. Any help would be appreciated

Regards and thanks
Frederick

 

[custard]

Hello Frederick, steam bending ply isn't a good idea because it will likely delaminate. The better choice is "Bendy Ply", google it, it's perfect for what you want.

Good luck!

 

[No skills]

I have done a vaguely similar chest for my daughter. The lid was convex curve from front to back.
I used 12mm ply for the base of the chest, for the lid I kerf cut the ply every 10mm (just leaving the last ply I think). To aid bending the last bit I poured two kettles of hot water over the plywood - bent it to shape and tied it with some string and left it to dry.
There was some delamination happening but only on the inner side where the kerfs were, as the box was being lined this didn't matter.
I got bits of pallet and cut 'veneers' from them and glued and pinned them on the ply box for an old timber effect.

 

[profchris]

I can't picture what you're aiming at (a sketch would help). But I have bent 3.6 mm hardwood ply to make a ukulele case:

I bent dry over a hot pipe, heated with a heat gun, and if I'd used a metal backing strip would have had no delamination ( there was a fraction on the tightest bend). The case is 24 ins long, and I doubt the ply could be bent to a much tighter radius.

10 ins is too great a width for bending on a pipe, but 10 1 inch strips would be easy.

 

[ComfortablyNumb]

Flexi Ply is what you want. Trying to steam bend it won't work as WBP Ply means water and boil proof glue

 

[profchris]

Flexi Ply is what you want. Trying to steam bend it won't work as WBP Ply means water and boil proof glue

I don't think the OP mentioned WBP, but even that would bend with heat.

Heat bending plasticises the lignins in the wood, allowing it to be bent to make eg guitar sides, which is how I use the technique. Steam bending of solid wood does the same, with the steam helping to get the heat into the wood.

But steam and sheet material don't work well, as the sheets often cup.

Bend/flexi ply is kerfed isn't it? Which means no smooth surface on the inside of a bend.

Heat bending can give you smooth both sides, but there is often scorching. No free lunch im afraid!

 

[Frederick]

Thanks to all for the help. I had never heard of Flexi Ply, so will try that first. Where there is a will, there is a way. PrtofChris put it very well indeed.....no free lunch....OH! how I wish at times..
What a great and helpful forum this is.
Cheers
Frederick

 

[Woodcrafts]

Bend/flexi ply is kerfed isn't it? Which means no smooth surface on the inside of a bend.

Profchris, I think you're confusing bendy/flexi ply with bendy MDF which is kerfed. Flexi-ply has smooth surfaces.
Both the ply and MDF will only bend in one plane, so compound curves are not possible.