Bendiply

[Hornbeam]

I am making a circular cabinet which will be made in sections, I am looking at using 1.5mm ply for the laminated sides but want to bulk the thickness out so was thing ing of using 2 central laminations of 5mm bendiply with 2 outer 1.5mm ply skins on each side, which will then have an external and internal veneer applied. I have never used bendiply but have a couple of questions

• Is it all the same quality or is it a bit like ordinary ply. some good some carp
• What is the glue quality
• I understand the laminations all run the same way. Is it dimensionally stable as I dont want to have movement issues if I am laminating it with thin ordinary ply
• Any other thoughts/comments

Thanks
Ian

 

[peter-harrison]

Hi, the stuff I have used has been pretty good. It's made from two thick plies running along the board, sandwiching a thinner ply running across. It's made from a fairly soft hardwood. I don't think you really need the 1.5mm ply- veneer either side would be perfect.
I have used it many times and haven't had any issues with stability. You do need to have a good 100mm over width when you're pressing, as you usually get a less well bent section at the edge.

 

[Sgian Dubh]

I've used it a number of times and it's put together as Peter describes. It's also pretty reliable for easy bending, but unlike Peter I think your plan for 1.5 mm ply as a ground for veneer would probably be beneficial, especially on the convex curve. I say this because the bendiply grain tends to open up a bit on convex curves therefore used under a 0.6 mm thick veneer the slight voids could telegraph through. However, if you use 1.5 mm plus veneer on one face then the usual 'rule' suggests do the same on both faces. Of course you could do a small sample of bendiply plus applying 1.5 mm plywood plus veneer, and a separate sample where the veneer is attached directly to the bendiply to help you decide on your procedure..

I've found that bendiply will occasionally cup across the bend, usually slightly concave. It's never been an issue in any projects I've used it for, and the cupping was always very slight, if it occurred, but it's worth being aware of that issue: some cross-strutting or internal framing might be needed, all depending on the nature of the project. Slainte.

 

[worn thumbs]

I'm not a huge fan of bendiply as I find the grain a bit pronounced.It will wrap round a curve nicely but as mentioned,it does tend to pull a bit flat without fairly generously applied framing to guarantee that the final shape is as you might wish it to be.

 

[Yojevol]

I've used bending on a few projects. The most relevant to this one is a 2m long serpentinious plinth for a very curvy cabinet. The front face of the plinth has both concave and convex curves and is 75mm high.
It is constructed with 2 bendiply strips seperated by 8mm vertical spacers about 65mm apart.
To assemble it I marked out the required curve on a sheet of MDF and attached a number of support blocks along the route.
Firstly I glued all the spacers on to one of the ply strips. I then glued the 2 strips together, starting at one end and clamping to the support blocks as I went. I used ìntermediate clamps to make sure the spacers were all well glued.
The end result is a very stable construction.
This method could, in principle, be used for your cabinet panel construction. It would need a sturdy former for gluing up. I would apply the veneer after construction using vacuum pressure kit.
I hope that gives further ideas on your project and I look forward to seeing the WIP.
Brian