Bendy Flexible Plywood

[Henry BuckeldeeParticipant @henrybuckeldee88769]

I am reupholstering a vintage car.

I am remaking curved boxes going over the wheel arches, ready to place carpet on top. The original boxes (Italian car) used a 3mm plywood over the curved sections of the box. I assume this was not heated to bend. I have bought some standard 3.6mm plywood, but there is no way this will bend over an approx 6 inch (150mm) radius.

Looking online there seems to a few different names for flexible bendy plywood, mainly targeted at modellers. Liteply is one name. The thickness that suits me would be 3mm, although a 2mm is also offered by some in the sheet size I want.

Does anyone have experience of this. Is this plywood suitable for an approx 6 inch radius.

Trimmers use what is called mill board, basically compressed paper. But I feel I want something a bit stronger than that. Preferably wood. So tacks can be used to secure carpet.

Any one know sources of supply. I need no more than 1/4 of a sheet. Of course this bendy ply bends perpendicular  to the veneer grain so need to check that out.

 

[JasonBModerator @jasonb]

You should be able to bend thin birch “skinply” or”aeroply” to that sort of radius. I’ve used it for lamination with a 200mm radius with no problem and it will bend a lot tighter than that. If you use two sheets with glue between then they will “set” to the curve once dry. Usually comes in 5ft square sheets.

Although I get most of my panel products from the link above this one tends to be more suitable for the public who just want a small amount an dwill roll a sheet up and send it to you

Several layers being laminated for this table I made

[BazyleParticipant @bazyle]

Liteply is just using balsa as the inner layer to reduce weight. Over ten years ago I made a lampshade from ply – so thin it is see-through as well as bending into a 10 in tube. However I don’t have any details from that long ago.

[parovozParticipant @parovoz]

Original probably steamed …..  Similar to hood hoops etc.

[bernard towersParticipant @bernardtowers37738]

Why not use two thicknesses of 1.5mm and glue together. I have done this in the past and it works well and dont forget that 3ply bends easily one way but not the other. Best of luck.

[Colin BishopModerator @colinbishop34627]

Liteply would be much too fragile. Jason’s suggestions are good, laminate for thickness as necessary.

Colin

[Michael GilliganParticipant @michaelgilligan61133]

Yes it exists [unidirectional plies]

https://materialsmarket.com/building-materials/sheet-materials/plywood-sheets/flexible-plywood

MichaelG.

[howardbParticipant @howardb]

“A newer method is kerf cutting, where grooves are cut into plywood, allowing it to curve smoothly. Kerf cutting involves making cuts along the back of the plywood sheet spaced closely together. These cuts, or ‘kerfs’, should not go all the way through; rather, they partially penetrate the plywood thickness, keeping the front intact. This partial cutting provides flexibility, enabling the plywood to bend around a curved form.

The number and depth of the kerfs depend on the desired curve’s tightness and the plywood’s thickness. Typically, the thicker the plywood, the wider and deeper the kerfs need to be. After bending the kerfed plywood to the shape needed, wood glue is usually applied within the grooves to secure the curve shape upon drying.

Clamping the bent plywood against a bending form ensures the desired curved surface is obtained. This is where bar clamps come into play, holding the plywood in position until the glue sets”

How to Bend Plywood – 2024 Guide

You could then use a thicker plywood than the 3.6mm plywood, say 5mm.

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