Bending Ply or Kerf Bend? Any advice appreciated

[Scotty1974]

Evening All,

looking for a bit of advice on a project please.

I want to make a curved worktop which will be laminated, just wondering if it would be better to use bending ply (2x8mm) or use 15mm ply and attempt a kerf where the bend will be?

The straight (or flat bit bit) would be around 1200mm long, didn't know if bending ply would play flat and straight along a length like this as I haven't used it before.

Any tips would be appreciated

Cheers

Scott

 

[Yojevol]

Not sure what you're talking about here - curved worktop?? Do you mean a curved edging or lippng? What is the nature of the worktop? What 'look' are you trying to achieve?
Brian

 

[Inspector]

If you glue the bending plywood while on a flat/straight form/table your finished piece will be the same.

Here is a calculator if you decide to go the kerfing route.
https://www.blocklayer.com/kerf-spacing
Pete

 

[Bingy man]

I would recommend a few sketches of what you intend to make. Are you doing this with brute force or using steam and or a former // clamps . I’ve no major experience of bending wood but recently tried to bend 25 mm decking around a bend - 1st attempt with multiple kerf cuts didn’t end well and I ended up cutting the board using angled cuts . I think 2x8 mm will be easier but you will need a method of holding it in the desired shape while any glue dries ..

 

[Doug71]

I haven't used it much but found bendy ply to be good stuff.

I have also used flexible MDF a bit which is kerfed, with kerfed things you need to be careful to not end up with the 50p piece look.........speaking from experience here

 

[AES]

I haven't used it much but found bendy ply to be good stuff.

I have also used flexible MDF a bit which is kerfed, with kerfed things you need to be careful to not end up with the 50p piece look.........speaking from experience here

+1. That's exactly the look I ended up with when I kerfed on ply too. In a couple of cases that didn't really matter, and the job was quite thick ply and allowed for filler, lots of sanding, and would be painted in the end anyway. Worked OK but a LOT of extra work.

On another job I used 1,5 mm bendy ply in five laminations (lams set at 90 degrees alternately), clamping up as I went. IF you can work out a way to clamp up nicely with NO creeps and/or gaps, it works fine, but an "exciting" time while clamping each layer!

HTH

 

[Jake]

Bendy ply is very soft and flimsy by design and would dent (and allow any veneer to crater on impact) - I wouldn't use it as a worktop material.

 

[Scotty1974]

Evening All,

Thanks for your messages and apologies for the late reply!

OK, in answer I'm revamping my VW campervan furniture and wanted to bend the worktop around the drivers seat.

Present setup is stopping the seat reclining into a comfortable position for me (6.4 height) apparently this is a common issue amongst the campervan conversions as they make the furniture as a standard size.

Soooo, wanted to either shorten the kitchen, which I can do, or alternatively create a curve downwards that will fit the profile of the van and the seat in a nice position to drive.

I've attached a rough (i do me rough!!) pic of the curve that is needed.

With regards to making a form I can do that as I have a CNC machine, so yes would be additional cost but not too worried about that, my main issue is whether to use bending ply (either 3x5mm or 2x8mm or to go with a 15mm Ply and kerf bend it.

Will be using HPL laminate for the surface of the worktop.

What do you think 3x 5mm maybe?

Cheers

Scott

 

[Scotty1974]

It's that sort of curve at the front. Ignore the back part as that will be flat and not curved

 

[Jones]

I think either would work. Adding Formica means the softness of bending ply wouldn't be an issue and equally you can add filler if a kerf cut comes out in segments. Glueing Formica down is fun, I find using cascamite is less stressful than evostick but not sure if that works on the curve.

 

[Hornbeam]

An alternative approach could be to make the curved section using staggered blockwork and then joint it to a flat top and end, particularly if you are going to formica afterwards. Easiest to do on a lathe and then cut the pice into quarters and glue up, but can also be built up and profiled using a bearing guided router cutter but you can only do it in stages

 

[Inspector]

An alternative approach could be to make the curved section using staggered blockwork and then joint it to a flat top and end, particularly if you are going to formica afterwards. Easiest to do on a lathe and then cut the pice into quarters and glue up, but can also be built up and profiled using a bearing guided router cutter but you can only do it in stages

The OP has admitted to owning a CNC (post 8) so is well setup to cut out the block work.

Pete

 

[Scotty1974]

Thanks guys for all your advice.

I'm going to try the Bending Ply route as I will need to make a form anyway for, so seems easier for glueing up etc.

So only question I have would it be better (stronger) to do this with 3x 5mm or 2x 8mm? I think I know the answer but just need a bit of reassurance as I normally only do flat stuff on the CNC

Will post some pics over the next week or so

Cheers

Scott

 

[stuart little]

I believe there is, or was, 'bendy' plywood available, a pal once gave me a piece of off-cut.

 

[RogerS]

I would use temporary formers cut slightly tighter than the final curve because it will spring back. Or are you curving in situ ? I've not used Bendy-Ply but would be checking how tight a radius can be bent ...is 5mm tighter than 8mm? What is your radius...if both 5 and 8 will bend enough then I'd minimise chances of creep and misalignment (accompanied by furious cussing) and go 2 x 8mm

 

[Jake]

I would use temporary formers cut slightly tighter than the final curve because it will spring back. Or are you curving in situ ? I've not used Bendy-Ply but would be checking how tight a radius can be bent ...is 5mm tighter than 8mm? What is your radius...if both 5 and 8 will bend enough then I'd minimise chances of creep and misalignment (accompanied by furious cussing) and go 2 x 8mm

Unlike built-up solid veneers, bendy ply (being layers of Weetabix between two very slightly more real thin veneers but both with the grain sideways to the bendy direction) is not going to spring back much at all once glued up. 3 x 5 is probably more stable than 2 x 8 given the weetabix nature of the stuff down the middle.