Bending Wood

Have you ever been interested in bending wood to create shapes that are difficult to do with just a saw, router, or carving tools. You can actually bend wood with a simple jig and a propane torch (or a heat gun). I show you how.

If you want to make something easy and practical, look at how I made a simple kitchen spatula below in step 5.

1. 1” by 6” and 1" by 8" black iron pipe nipple. Do not use galvanized pipe!!
2. 1” black iron flange, 1" end cap, and 1" tee, again do not use galvanized!!
3. For larger diameter bends use 2" pipe and fittings instead.
4. Propane torch
5. Heat resistant gloves
6. Various clamps
7. Thin strips of wood for bending
8. Wood for templates and clamping forms

Build the simple jig as shown in the pictures and drawing. I used the 6" pipe nipple for the horizontal part that will serve as the heated bending tool. Clean the pipes to remove any grease and black coating. 100-grid sand paper works great. I drilled a couple of ventilation holes into the end cap so that the propane flame will not starve. You can try the jig without the end cap, but watch out for the hot air exiting the end of the pipe! The propane torch is supported by a hand screw clamp; you could build something nicer and more permanent. Yet the hand screw gives me a lot of flexibility adjusting the torch, and secures the torch pretty well!

Prepare some wood strips for bending. The strips should be no more than 1/8” thick, and have straight grain, ideally quarter-sawn. The following wood species work well:

Red oak, white oak, ash, maple, cherry, walnut, hickory

Make a template for the desired profile. The template will help during the bending process to gauge your progress and to clamp the piece for drying and/or laminating. On larger templates drill some through-holes to facilitate clamping. The pictures show some small templates I made from a 2 by 4 for testing purposes.

Soak the wooden strips in hot water with a few drops of dish soap added. Let them soak for an hour or longer, even overnight. Short pieces can be soaked in the sink. For longer pieces get a PVC pipe, cap the lower end, fill with water, and soak your wood strips.

The video shows me bending some oak strips of about 1/16" to 3/32" thickness.

Clamp the jig securely to a workbench. Position the propane torch as shown and turn on the flame. You want the surface of the pipe nipple to come up to about 200 - 220 degrees F for optimal bending without burning. I use an infrared thermometer for measurement; this is especially helpful to find the location on the pipe that is in the right temperature range. Adjust the flame to maintain the temperature, and be sure the pipe does not get too hot during the bending process. If you have problems with burning turn off the torch, let the jig cool to 220 degrees F, and then use for bending. Minor burn marks can be sanded away after the piece dries. Never leave your jig unattended with the propane torch on, and use the jig only in a well ventilated area.

Take a soaked wood strip, wipe dry, and carefully bend over the hot pipe - wear gloves for protection. Take your time and don’t apply too much force; the wood might crack. Move the strip back and forth across the pipe. As the wood heats up and the lignin softens, the strip becomes pliable and bends easily. Again, go slow and easy. You may have to practice a few times to get it right. No matter, you will crack, break, or misshape some of the strips. For practice use wooden strips no thicker than 1/16”, it will help you develop a feel for it.

During the bending process the soaked-up water will turn into steam and soften the lignin; and the wood will dry. You may rewet the wood strip for further bending, especially with thicker strips.

The outside of the 1" iron pipe has a diameter of about 1-3/8 inch, so that is the tightest bend you can make using this pipe.

Once you have achieved (or approached) the desired bend profile remove the strip from the heat and clamp it to your template. Allow it to dry thoroughly. I found that with this method you have very little springback.

It's not easy to bend wood strips thicker than 1/8" using this method, especially for tight bends. In order to make thicker pieces e.g. for furniture, you can laminate several bent strips into a more solid piece.

The lamination process works best with a template or clamping form consisting of two parts. The two parts have a similar profile but they have to account for the thickness of your final piece. If you wish to make a 1/2" thick curved wood arch with a radius of 10" then the convex form is cut with a 10" radius and the concave form is cut with a radius of 10.5".

First, bend each strip to match your profile closely. Wrap the strip around your convex form and clamp. Repeat for each additional strip and add to the form. After a few strips add the second part, i.e. the concave part of the form. Once you have reached your desired thickness (e.g. 1/2”) clamp the assembly and let dry for at least 24 hours. The pictures show 7 oak strips assembled into a 10" arch.

When dry, unclamp and label the position of each strip, i.e. innermost to outermost strip. Apply wood glue, reassemble in the proper order, and clamp again using both parts of the form. Let dry for at least 4 hours, overnight is better.

To finish, plane or sand the edges of the laminated piece, or run through a jointer. Depending on the wood grain you may not be able to distinguish the individual strips, and your final piece looks like solid wood.

Start with a board that is 2.5" by 12" by 3/16" thick. Use the attached template to cut and shape the spatula, sand, round the edges, and engrave (optional!). Then fire up your bending jig. The center and extend of the bend is shown on the template. Start heating/bending from the center line and make a bend of about 15 degrees. The spatula and it's angle should feel comfortable in your hand. I had some burn marks from the bending process; no problem, just sand it clean.

Once you have achieved the desired bend, taper the front edge of the spatula using a file, rasp, and/or sander. Optional: finish with a food safe oil.

A cute and weird little sculpture I made!