Bendable plywood

[Ron Hitchcock]

I'm looking for someone with some experience veneering bendable plywood. I'm making a half of a heart shape. I've tried a few experiments, not able to get the shape exactly. I'm using ratchet straps to clamp it together. I believe I need to start wrapping from the centre of the curve as opposed to starting at one end. My question is can I use just one layer of veneer on each side. The plywood is 5/32. I'm using a powdered resin glue, which seems to work just fin.

[roger wiegand]

I've never tried veneering both sides at once other than with a two part form-- which didn't go so well. I've used a bending form or the actual interior structure of the bent piece on the inside and either vacuum bagged it to apply veneer to the outside or used a two part form. Most things I've made with bending ply have something on the inside that the plywood gets attached to with glue and or fasteners that holds the shape in place. I know it violates the rules of veneering, eg equal layers on each side, but for making tubes or curved sections it seems to have worked. If I needed a finished surface on both sides again I'd probably vacuum bag on an inside and outside form in two sequential steps, not try to do it all at once. I'm sure others who do more architectural stuff have much more experience with this sort of thing than I do; I've only done it a half dozen times.

I'm always surprised at how well it seems to come out and how much fun it is to add a curve with "wiggle wood".

[Maurice Mcmurry]

I have used store bought 3 ply bending plywood as well as made my own two ply by planing or re-sawing regular plywood. I have also made multi ply layups of veneer. My methods are similar to those described by Roger. Using straps around a form has worked well for me. The big curve pictured is two layers of two ply. The smaller curve is several layers of backed veneer. These were done one glue up at a time. To glue several layers at once you need a very well designed form and a press or clamping system. Depending on what you are making, creating balanced laminations is not as important for curves as is for making things you want to stay flat.

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[Kevin Jenness]

Per usual, pictures would help. If the surface is smooth and fair one layer of veneer is fine. I have used 3 ply 8mm lauan bending ply and 2 and 3 ply 3mm birch and poplar for cores. The thicker stuff is quite coarse and usually needs some tuning up before laying the face veneer, the thinner stuff not so much. If you have a decent convex form you can probably succeed with ratchet straps and a caul. If your heart shape has a recurve or concave section that will probably need clamps or vacuum. If you had trouble bending the substrate into shape with strap clamps the face veneer will likely also be problematic. A dry run is never a waste of time.

[Ron Hitchcock]

Sorry about the picture, wasn't thinking. The form is in the shape of a tear drop made from 12 pieces of plywood and mdf, then wrapped in formic. In the past I started at one end, but I ended up with a couple of ripples around the curve. A dry run didn't show that. LOL So, I thought start at the curve and I'm using cawls on straps, at equal distances, so they can't move. Less veneer might make it easier. The project is a urn for the wife and I. Thanks everyone for sharing their opinion.

[Richard Coers]

For an urn, 1/4" wall thickness would be plenty. Sitting on a shelf doesn't need any strength at all.

[Richard Coers]

For an urn, 1/4" wall thickness would be plenty. Sitting on a shelf doesn't need any strength at all. I have no idea where you are using 12 pieces of plywood