Hot Pipe Wood Bending

Intro: Hot Pipe Wood Bending

I've always been intrigued by bent wood. However, I can't afford a steamer nor do I have space to store a steam box. I came across this technique in an old issue of American Woodworker (now shared online here). Instead of placing your wood inside a steam box, you soak your wood overnight then create steam inside the wood by the use of a heated pipe. It's a quick process that produces surprisingly great results.

If your already have a torch and scrap wood, you have 90% of the required materials for this hot pipe bending jig.

STEP 1: Tools and Materials

Materials:

• 8 in. long 3/4 in. diameter Black Steel Pipe
• 3/4 in. Floor Flange
• Wood
• Propane Torch
• Bucket of Water
• Spray Bottle
• Screws

Tools:

• Saw
• Drill

STEP 2: Remove Pant From Pipe

Using some sandpaper remove the paint from the black iron pipe. To be safe, I'd suggest not using galvanized pipe for this application as if it is heated too hot, it can release toxic fumes. For this process your pipe should never get hot enough to produce these toxic fumes; but again, just to be safe.

STEP 3: Create Torch Rest

Cut pieces for the torch rest from scrap wood. I had some old MDF tha had been run over by my car (notice the tire marks). Secure the supports in place with screws.

STEP 4: Cut Front Support and Position Hole

Cut a hole in the center of the front board two inches from the top. This will be where the end of your torch comes through. Position the front and secure in place.

STEP 5: Attach Flange and Pipe

Using machine screws and t-nuts, attach the flange in place. I opted for this instead of wood screws because I didn't want them to tear out over time. I was missing one t-nut but I will add that in place later.

STEP 6: PVC Torch Clip

Cut a ring from a piece of 4 in. PVC. Cut about one fourth of the ring away. Cut the profile on a piece of scrap wood that fits in between the supports then attach it to the jig with screws.

STEP 7: Setup

Clamp the jig to your workbench, you don't want a hot pipe and torch to fall or move while using it.

You want the temperature to be as low as it can be with propane. The flame should just be coming out the end of the pipe as shown in the second picture. If it's loud and shooting straight out the end of the pipe, it's going to be too hot and will burn the wood.

STEP 8: Bend Wood

Soak the piece of wood you are interested in bending overnight. I haven't tried anything over about 1/8 in. thick. Press the wood against the hot pipe. After a few seconds you should feel the wood weaken and start bending. Remove the wood from the pipe every 5-10 seconds and dip or spray the wood with water. This will introduce more moisture in the wood and keep it from burning. Bend the wood to whatever shape you like or need. I bend this piece of walnut into two loops. I was surprised at the ease and efficacy of this process.

What bent wood projects have you created? Have you tried hot pipe bending before? Share your stories in the comments!

Comments

[Maziyar1349]

Thank you very much . it's very efficient .

[marc.mat.johnston]

Any thoughts on using this method to bend a wooden pipe/tube.
Wet sand capping the ends possibly?

[tomatoskins]

I'm not sure how well it would work as it would get the heat all the way around the wooden pipe.

[Mack Q]

Excellent, a couple of years back I made a steam box along with soaking over night - did night work - was trying to bend 1/2" for an arch trim over door,, will try this, thanks

[baecker03]

I'd use a piece of cedar or pine for the board that the pipe is screwed to... Mdf releases some nasty fumes if it burns at all... At least with cedar or pine, you get a nice pleasant smell that won't leave any toxic fumes. But anyhow, very neat project!

[pgs070947]

Some of the lovliest furniture has been bent-wood. Real classics from G-Plan and Bauhaus have been in bent ply. Many utilitarian chairs have had totally bent-wood frames, simply because it avoids costly and weak joints.

[vincent7520]

Beautiful ! …

[jongscx]

With the flame shooting right through the tube, isn't most of your heat going to go out the end of the pipe? Have you given any thought to making this more efficient or is that unnecessary?

[offramp]

A suggestion might be to put a cap on the end of the tube, yet drill some tiny vent holes on the underside of the tube, to let vapors escape.

[tomatoskins]

You could cap off the end, but I'd be worried about where the burt gas is going. Along with that, you don't want to keep all the heat from the torch as propane with a blue flame can get upwards of 2000 degrees F and that's too hot for this purpose.

[JohnC430]

do you know or can you make a guess to what temp the pipe gets? at what temp will the wood start bending. i am assuming that in order to generate steam if has to be over 100C but how much more? does anyone in these posts know?

[JGDean]

While it's not too critical, the temperature should be 115 - 150°C (240 - 300°F) It needs to be hot enough to create steam fairly quickly, but below the point where the wood chars too quickly or begins to burn, which can happen above 150°C. Some woods can char at these temperatures, but slowly and it can be controlled.

[JohnC430]

thanks for the explanation

[vamrhein]

What is the tightest bend you can make

[tomatoskins]

It would be the radius of the pipe being used. I'm not sure what the limitations of the wood are however.

[lonesoulsurfer]

Do you have good control of the bends? Also, have you used different types of wood and if so what did you find worked the best? Great ‘ible by the way :)

[tomatoskins]

I have had no trouble with controlling the radius or locations of the bends. I assume any type of wood that bends traditionally should bend with this method. Birch, Ash, Oak, Beech, Elm, and Cherry should all be fine I assume (as long as they are air dried and not kiln dried). I've only tried walnut as that is the wood I am needing to bend for an upcoming project. Give it a try and let me know what woods work for you!

[lonesoulsurfer]

Cool thanks Tom.
I was thinking of using a larger pipe to make a larger sized radius. I'll let you know how I go.

[Yin YangG]

i made mine using 2 inch pipe....to bend acoustic guitar sides.......worked great. i used a barbecue grill charcoal lighter for my heat source, but i think the propane torch is a better idea.......i have the far end of the pipe capped off, so maybe i need to open that up for the torch?

[tomatoskins]

That is beautiful! I am not sure if the open end is necessary or not and it actually might be for larger diameter pipes like yours.