How to Bend Wood with Steam

Meet the Expert

Project editor Jay Cork has taught classes on bending wood with steam. Truly, no one is more full of hot air.

How Does Wood Bend?

Some wood species — ash or oak, even cherry or walnut — can be bent by softening their lignin with heat. Think of lignin as the glue holding the wood fibers together. As the lignin and fibers are heated, they become pliable for a short time and the wood can be bent around a form.

Air-Dried is Best, But …

It’s a common misconception that only air-dried lumber bends well. I have found this to be only partly true. Kiln-dried lumber has a bad reputation because during the drying process, the lignin cooks and becomes stiff. If this happens, no amount of heat will bring it back.

Despite this risk, I’ve found kiln-dried wood can indeed be bent if it’s steamed for a longer period.

Build the Steam Chamber

Cut the box parts

Size the steam chamber to the parts being bent; any larger will waste heat energy. The box can be made from any wood — even PVC pipe!

• Pro tip: I chose CDX ­(exterior) plywood because it’s cheap, easy to work with and holds heat better than PVC pipe.

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