Flexible Plywood

Flexible plywood for curved work

Ordinary plywood is stiff because its layers are glued at right angles to one another, so whichever way you try to bend it, something is resisting. Flexible plywood is built the opposite way. The grain is arranged so the sheet has almost no stiffness in one direction, and it will roll up like a carpet along that axis.

The trade off is that it is floppy rather than strong. On its own it will not hold a shape or carry anything. It is a skin: you bend it to a curve and then either fix it to a frame or glue two layers together so the pair becomes rigid.

Long grain and cross grain, and why it matters

This is the one thing to get right, and it is where most wasted sheets come from. Flexible plywood bends around one axis only. Long grain and cross grain sheets bend in opposite directions, and they are not interchangeable. A sheet that bends the wrong way for your job is no use at all, and trying to force it the other way will simply crack the face.

The way to work it out is to picture the finished piece and ask which dimension of the sheet has to wrap around the curve. If you are making a curved column casing two metres tall, the height stays straight and the width wraps. If you are making a low curved bar front that runs a long way around a bend, the length wraps and the height stays straight. Those two jobs need different sheets.

Measure the curve, work out which dimension has to follow it, then check the grain direction in the product name before you order. Long grain and cross grain are listed as separate products in each thickness, so you pick the direction as you add the sheet to the cart. A sheet bought the wrong way round cannot be bent to your curve, so this check is worth the minute it takes.

Flexible plywood sheet sizes and thicknesses

Every sheet is 2440×1220 mm, the standard 8×4 foot size, and the range comes in two thicknesses, each made in both grain directions. That gives you four sheets to choose from:

• 5 mm long grain (2440×1220 mm): tight radius work such as rounded cabinet ends, small radius column casings and curved drawer fronts.
• 5 mm cross grain (1220×2440 mm): the same tight radius work on curves running the other way, such as curved bar and counter fronts, arched openings and door heads.
• 8 mm long grain (2440×1220 mm): gentler curves on bigger work, such as large curved wall panels, big column casings and sweeping bulkheads.
• 8 mm cross grain (1220×2440 mm): long sweeping curves running the other way, such as bar and counter fronts, curved shopfronts and wide radius walls.

5 mm or 8 mm

5 mm bends to a tighter radius and is the easier one to work with single handed. Use it for smaller curves, tighter radii, and anywhere you are laminating two layers over a former. See the 5 mm long grain flexible plywood for tight curves like rounded cabinet ends.

8 mm will not come round as tight, but it is stiffer once it is fixed and it needs less support behind it. Use it for gentler curves and larger panels, or where the frame behind is more widely spaced, as with the 8 mm long grain flexible plywood.

If you are unsure, remember that two layers of 5 mm glued together will usually outperform one layer of 8 mm, because the lamination locks the curve in permanently. That is why many curved jobs are ordered in pairs of 5 mm sheets.

What people use flexi plywood for

Bendy ply goes wherever a flat sheet has to follow a curve. Shopfitting takes most of it, but it is just as useful at home:

• Commercial fit outs: curved bar and counter fronts, reception desks, seating pods and display stands.
• Walls and ceilings: column and pillar casings, curved bulkheads, radius walls and curved stair bulkheads.
• Openings: arched openings, curved door heads and an arch over a doorway.
• Joinery at home: rounded cabinet ends, a curved kitchen island end, curved shelving, window seats and boxing in a rounded corner.

How to bend it properly

For anything permanent, laminate rather than rely on a single sheet. Build a former in the shape of the curve, glue two layers of flexible ply together over it, clamp them well and leave them until the glue is fully cured. The result holds the curve on its own and is genuinely rigid.

Expect some spring back. When you take the clamps off, the shape will open up slightly from what the former gave it. Build the former a little tighter than the finished curve so the piece relaxes into the right shape rather than out of it.

If you are fixing a single sheet to a frame instead, support it more often than you think. The gaps between the ribs will show as flats on the finished curve, and once it is skimmed or veneered those flats are very hard to hide.

Cutting and handling it

It cuts easily, but it will not hold itself flat while you do it. Support the whole sheet on a bench or on battens across trestles, because an unsupported flexible sheet sags into the blade and the cut wanders.

Use a fine toothed blade and take it steadily. The core is soft, so a coarse blade tears rather than cuts and leaves a ragged edge that shows up later through a veneer or a skim.

Store it flat, or rolled if you have space, but never leaning against a wall. Left standing on edge it takes a permanent kink where it touches the floor, and that kink will not press out again.

Handle it flat too. Carrying a sheet on edge folds it under its own weight, and a hard crease across the face is a crack waiting to happen once you glue it to a curve.

Finishing flexible plywood

Flexible plywood is not a finished surface. The face is plain and open grained, and it is meant to be covered.

Most people veneer it, laminate it, or skim it with a thin filler and paint it. If you are painting, fill and sand the face properly first: a curved surface catches light along its whole length, so any texture in the face shows up far more than it would on a flat panel.

Flexible plywood or another sheet?

Flexible plywood is the sheet to choose whenever the radius is too tight for ordinary board, because it is made to bend. On a gentle sweep, a thin birch plywood sheet will take a soft radius straight off the sheet and gives you a smooth, hard face that can be left on show. For flat panels behind or around the curve, such as the carcass of a curved counter, hardwood faced plywood is the stiffer everyday board to pair it with.

People also search for flexible MDF for the same jobs. Flexible plywood covers that work: it bends to the curve, holds it once fixed or laminated, and takes a veneer, laminate or painted finish in the same way.

Flexible plywood in Dublin and across Ireland

All four sheets are stocked in our North Dublin warehouse and delivered across Ireland, and both thicknesses are light enough to handle on your own: a 5 mm sheet is 8.1 kg and an 8 mm sheet is 13 kg, so getting one into a car and cutting it single handed is realistic in a way it is not with most sheet materials. The difficulty with bendy ply is the floppiness rather than the weight, so keep it flat on the way in and get a second pair of hands for the walk from the van if the ground is uneven.

Before you order, have the direction of your curve worked out and pick the grain to match. The calculator on each product page works out how many sheets your curved area needs, and if you are laminating two layers, double the count.

For every other grade, from birch to marine and softwood sheets, see our full plywood range.