How to Bend Wood at Home

Kerf Method to Bend Wood

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Overview
  • Working Time: 1 - 2 hrs
  • Total Time: 1 - 3 days
  • Skill Level: Beginner
  • Estimated Cost: $20 to $50

Bending wood transforms solid, straight wood into graceful curves. It’s often an adjunct to another project, such as building furniture, baskets, musical instruments, toys, or crafts. It’s also fun to play around with on its own. 

Bending wood is a two-step process: first softening the wood, then forming it. Steam is a good agent for softening wood. Wood can also be softened by creating multiple cuts on the back of the wood. This method is called kerf-cutting.

Bending Wood With Steam

Wood can be soaked in water to soften it. Heating the water above 212 F (boiling) to create steam softens the wood faster. The softened wood is clamped into a frame and left to dry. 

You’ll need to build a steam box to hold the wood during the steaming. A steam box can be made of nearly any heat-resistant, waterproof item of sufficient size. 

A steam source, such as a steam cleaner, is attached by a hose to the steam box. The steam box must be vented at the top to allow the steam to escape, thus relieving pressure. It also must have a drainage hole (or weep hole) at the bottom to drain off condensation.

After steaming, the wood is placed in a frame that bends it to the correct size. After the wood dries, it can be removed.

Best Types of Wood For Steam Bending

The thinner and smaller the wood, the better it works for steam-bending. Sheet materials are difficult to steam-bend because of their size.

White oak, hackberry, and red oak bend well. Soft maple, yellow-poplar, and hard maple are poor wood species for steam-bending. 

Wood is generally bent perpendicular to the direction of the wood grain. Bending the wood parallel to the grain can crack the wood. 

Pros
  • Green; no chemicals

  • Softens all of the wood, not just one side

  • Bends are permanent

Cons
  • Excess moisture

  • Potential for scalding

  • Steam box must be built

  • Must be formed in a frame

  • Significant waiting time

Bending Wood by Kerf-Cutting

Kerf-cutting requires no soaking or steaming, so no waiting time. Multiple incisions are created in the back of the wood with an electric saw. This makes the wood flexible enough to bend. Even thick wood and large sheet goods can be bent by kerf-cutting. 

For kerf-cutting, nearly any type of wood can be used, even composites like particleboard or Masonite.

Try to bend kerf-cut wood perpendicular to the kerfs, if possible. But you can bend the wood parallel to the kerfs, too. Just be careful to bend the wood slowly and carefully to avoid cracking.

Pros
  • No soaking or steaming

  • Clean

  • More control

  • No waiting time

  • Thicker materials can be bent

Cons
  • Requires a miter saw or radial saw

  • Only one side of the wood can be visible

  • Creating multiple cuts can be tedious

Safety Precautions

  • Steam Bending: Steam can injure you. Be careful when opening the steam box. Handle only with heavy gloves and use safety glasses.
  • Kerf-Cutting: Observe all of the safety requirements for working with electric saws.

What You'll Need

Equipment / Tools

Steam Bending

  • Steam source
  • Screwdriver
  • Cordless drill
  • Utility knife
  • Spring clamps
  • Heavy gloves
  • Eye protection

Kerf-Cutting

  • Miter saw, table saw, or radial saw
  • Kerf saw blade
  • Pencil
  • Eye and hearing protection

Materials

Steam Bending

  • Wood
  • Scrap blocks of wood
  • 4-inch PVC sewer pipe
  • 4-inch PVC sewer pipe solid cap
  • 4-inch rubber gasket
  • 2-inch hose

Kerf-Cutting

  • Wood
  • Wood glue

Instructions

How to Bend Wood With Steam

  1. Build the Steam Box

    Attach the solid cap to the end of the sewer pipe. At the other end, attach the 4-inch rubber gasket. With the utility knife, cut a 1-7/8-inch hole. Force one end of the 2-inch hose in the hole. Attach the other end of the hose to the steam source. Drill several weep holes at the bottom and several more at the top to relieve pressure.

  2. Prepare the Steam Box

    Remove the rubber gasket. Place the steam box in an area such as a garage or outdoors, where the flooring will not be harmed by excess moisture. Put the boards to be bent in the steam box and elevate them on wood blocks. Replace the rubber gasket.

  3. Build the Frame

    Using plywood, lumber, or clamps on a workbench, create a frame for shaping the wood as it dries.

  4. Activate the Steam Source

    Turn on the steam source and bring it to boiling temperature. A general rule of thumb is to steam wood for about one hour per 1-inch of thickness.

  5. Remove the Wood

    When the wood has finished steaming, remove it immediately while wearing thick gloves.

  6. Let the Wood Dry

    Quickly place the wood in the frame. Overbend the wood by about 5 percent because there will be some bend-back after the wood is removed. Let the wood dry for about three days.

How to Bend Wood by Kerf-Cutting

  1. Set the Saw Blade

    Adjust the saw blade’s depth to about 1/8-inch less than the thickness of the wood.

  2. Mark the Range of Cuts

    Unless you will be bending the entire material, mark the span of the bend with a pencil or painter’s tape.

  3. Make the First Cut

    Turn on the saw and run the blade across the material, beginning at one end of the bend span.

  4. Make Subsequent Cuts

    Keep making additional cuts, maintaining a distance equaling the width of the saw blade. Continue until you reach the end of the bend span.

  5. Bend the Wood

    Kerf-cut wood can be bent by installing it in its eventual installation area. For example, to make a bend in a wall, the panel would be nailed into place. The nails hold the wood’s bend. 

    Alternatively, you can fill in the kerfs with wood glue, bend the wood into a frame, and leave the glue to dry. This works best for outward wood curves, not inward curves. For inward curves, you’ll need to build a supporting frame in back to hold the bend.

About Bending Wood With Chemicals

Treating wood with a gas created by a solution of 75-percent water and 25-percent ammonia can soften the wood fibers enough to bend them. This method is especially good when you need to bend the wood sharply or create curls.

This method is not recommended for do-it-yourselfers. A tight chamber must be built so that the wood can be subjected to an ammonia gas under high pressure. While it’s a highly effective process, set-up is difficult and the potential for injury is great.