by Grant Campbell

Created on: March 20, 2007   Last Updated: May 04, 2007

How To Bend Wood

Wood bending is not as daunting as it may appear at first glance. Wood may be bent by laminating thin strips together in a mold, or "glulam" as it is called, by hot bending as in the case of stringed instrument sides, wet bending, or through the use of steam, which calls for some specialized equipment. The method is dictated by the individual job, and depends on whether or not the bend is compound, as well as the degree of bend.

First, you need to have a form to bend your wood around and clamp to, to hold the desired shape. Most bent wood will have a certain degree of "springback", so you must build your form with an allowance for this. Unfortunately, there is no established formula for determining the degree of springback that a given species of wood will produce. Springback is also influenced by the bending method used. That is to say that steamed wood will spring, or "unbend" more than wood that is laminated and glued.

Another variable is the type of glue used in laminating. As a general rule, the tighter the bend, the more the wood will spring back, making the allowance a matter of trial and error at best.

As laminating thin strips is the easiest method, we'll begin with that process. The finished thickness of the project will have a direct bearing on the size of the strips to be used, but generally, the heaviest strip to use is about " thick. Tight bends may have to be done with 1/8" strips or thinner, depending on the wood species. Sounds like a lot of experimenting, but I'm afraid that's a necessary evil.

The form required for laminating can be as simple as a piece of pipe or as complex as a multi-station die. I like to keep things as simple as possible.

When laminating thin strips, you can minimize effort and spring back by soaking the strips before bending, and clamping them in the mold without gluing. Once they are dry, remove them from the mold, spread the glue and re-clamp them in the mold. Line the mold with waxed paper to prevent the lamination from sticking to the mold.

When I soak strips, I do so in an open container, and, depending on the wood and the size of the strips, I soak them from 15 minutes to overnight. I also mix in a half cup of fabric softener per gallon of water. I find that it softens wood nearly as well as fabric.

If the project is small, and open time on the glue is not a factor, I'll use a poly-vinyl acetate, or an aliphatic resin glue. If I need more working time, I'll use epoxy or resorcinol. I stay away from the

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