The Method: Michael Fortune’s Guide to Steam Bending Wood

Steam bending is one of woodworking’s most rewarding techniques, and one that is at risk of becoming a lost art. It allows makers to shape wood into flowing, organic forms that would be impossible to achieve with cutting or joinery alone. For an experienced furniture designer like Michael Fortune, steam bending has become second nature. Having designed furniture for over 50 years, it is his go-to method for adding movement and interest to his works of art.

Understanding the Principle

At its core, steam bending relies on a simple relationship between heat, moisture, and wood fiber. When heated with steam, the lignin inside the wood softens, allowing the fibers to stretch and compress. Once cooled and dried in a form, the lignin hardens again, locking the piece into its new shape.

Michael’s success with steam bending has a lot to do with milling his own lumber. When purchasing lumber, it is often kiln-dried, meaning it has been exposed to high heat. This causes the lignin to completely solidify around each wood fiber, making it unusable for steam bending.

Although air drying is the optimal way to prep your wood for bending, Michael has built a solar kiln on his property to speed up the drying process. Since it only gets up to about 125°F (52°C), it is not hot enough to affect the lignin.

Choosing the Right Material

Before you can bend, selecting and preparing the right wood is essential.

Species: Michael has bent many different varieties of wood over the years. He uses balsa wood for all of his prototypes because it grows extremely fast, it’s light, and easy to work with. Walnut, cherry, and ash are among his favourite varieties to bend for his final pieces.

Grain: When milling into a log, revealing the colours and grain is a joy. “You open a walnut log and you’ll see blues, greens, and purples. You don’t see that in kiln-dried wood.”

Moisture Content: Michael uses air-dried wood but will sometimes kiln-dry his lumber at a low temperature in his solar kiln. His ideal moisture content is around 6–9%.

Preparing the Steam Box

Michael has many steam boxes, all different lengths and sizes depending on the piece of wood he would like to bend. His setup is simple but efficient.

He sets the box on sawhorses and connects a steamer from underneath. Once the box heats up, he slides the wood in, sitting on a rack so that the steam can penetrate all sides of the lumber.

The box must maintain a steady temperature of about 212°F (100°C) for the wood to soften. When determining steaming time, thickness matters more than length. Generally, you will leave the wood in the steam box for one hour for every one inch of thickness.

When it is ready, it will be hot. When opening, keep your face away from the door of the box -“or you’ll know what a lobster feels just as it’s on its way into the pot,” Michael jokes. Heat gloves are important when handling the wood straight out of the steam box because it can burn you.

Bending Process

To get the desired shape, he bends the wood around the steam bending form and traps it there until it cools. The form is first attached to his homemade workstation.

Michael bends his wood on a custom-made workbench that was inspired by a welder’s table. The holes across the surface let him secure the wood with pins as he bends and clamps it to the form.

Position the Compression Strap: When he brings the wood in from the steam box, it is immediately attached to the end stops and compression straps that are intended specifically for bending wood. The compression strap keeps the outside of the bend under pressure, preventing tension cracks as the wood curves. Michael designed the steam bending accessories that are needed, and they are manufactured and sold by Lee Valley.

The wood is then tightly clamped to one side of the form. There is an incredible amount of leverage created when bending the wood, so a block is placed beside the wood to prevent it from coming away from the form.

Bend Slowly and Clamp Often: Once the wood is firmly in place, the bending can begin. Michael will slowly lever the wood around the form so that it compresses to the shape. This is done in small steps, stopping periodically to add a clamp to the form. He is able to put large pins in the table to hold the wood in place while another clamp is added.

Give it Time to Cool: Once the wood is completely bent to the shape of the form, a final pin and clamp are placed, and the wood is left to cool on the form. It is trapped between the form and the bending strap while it cools. Sometimes he will add a fan to speed up the cooling process.

Once cool, Michael will put the piece on a drying rack and move on to the next piece he needs.

Note: The compressive force is not dangerous. If something were to break during the bending process, it would just fall apart. “I won’t be slammed against the back wall of the workshop,” Michael assures.

Integrating the Bend into Design

Over the years, Michael has built a personal library of bending forms, each a record of what worked, what didn’t, and what might inspire the next idea.

What makes Michael’s method exceptional isn’t just his precision, it’s his mindset. His technique is less about memorizing steps and more about developing awareness. Steam bending demands an intimate knowledge of the wood, and Michael observes the materials closely and has a deep understanding of how to bend the wood to achieve his vision.

A successful bend adds movement to the piece and is a reminder that craftsmanship is a dialogue between maker and material.

To learn more about Michael Fortune's designs, check out The Maker: Michael Fortune, Mastering the Art of Furniture Design.