Bent Lamination

By David J. Marks

The ability to bend wood opens a whole new vocabulary of design expressions.

Once you add these techniques to your collection of woodworking skills, you’ll find that you are finally able to work outside the box. I mean, you’ll no longer be locked into fitting one flat plane of wood into another. The craft of lamination has been around for thousands of years. It was used to join blocks of wood together to create wood sculptures in the Middle Ages, but because glues back then were unreliable, craftsmen had to use dowels or other fasteners to hold pieces together. Modern adhesives have eliminated any concerns about delamination; the glue lines are now as strong as the wood itself.

The process of bent lamination consists of slicing wood into thin strips, coating it with glue and clamping it to a form until the glue dries. I have found the even the hardest woods are capable of being made into fluid curves with this technique. The first step is to draw a full scale template of your curve, and then build a form. Medium density fiberboard can be used for mild curves but if there is a lot of stress from a steep curve then you’ll need a stronger material, such as plywood. Fir plywood is the most economical choice and is quite strong.

Depending on the design, you can make a one part form or a two part form. A one part form consists of a simple curved shape and utilizes clamps to hold the laminates in place. A two part form has the advantage of requiring fewer clamps and does a better job of distributing the pressure. I’ll often line my forms with an eighth inch layer of cork to help maintain uniform clamping pressure and to compensate for any irregularities in the form. Adding a layer of clear plastic tape helps to ensure that the laminates don’t get glued to the form.

As for resawing the stock, you can rip laminates on the table saw, but I prefer the bandsaw. The bandsaw is much safer and you will have a narrower kerf which means greater yield. I use a bi-metal blade with six teeth per inch. I’m also using a straight fence which I set to compensate for the “drift” of each blade. Generally the cuts are clean enough to go right to a glue up but if you have a drum sander, you can improve the surface.

Over the years, I have experimented with many types of glue, however I find I get the best results with a slow setting plastic resin glue. Weldwood is available at most hardware stores and works fine. Unibond is also an excellent choice.

If you like the idea of incorporating curves into your designs, you’ll be amazed at how learning these techniques can open up a whole new way to express your ideas.