Get Bent: Build a Steam Rig for Under 50 Bucks

This week, I was finally ready to steam-bend the crest rail for my Windsor chair. The only problem was that I didn’t have a steaming rig. As with so many things in woodworking (and probably any other hobby), you can spend about as much or as little as you want to spend to get yourself set up for steam-bending. I tend towards the “spend as little as possible” end of the spectrum.

So with that in mind, I dropped by my local hardware store and Wal-Mart and picked up the parts I needed to cobble together a functional steam rig for as little money as possible. The total tab was very reasonable for a rig that should last for many years.

Here’s what I bought:

  • 1 – 5′ length PVC 4″ pipe, schedule 40 ($12)
  • 2 – 4″ cleanout caps ($6)
  • 1 – 24″ length braided 3/4″ water heater pipe with threaded female ends ($11)
  • 2 – 3/4″ double male threaded iron adapters ($2.50)
  • 1 – hot plate ($11)
  • 1 – tea kettle ($6)

Total cost: $48.50

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Considering that many people pay $80-$100 just for a wallpaper steamer to produce steam, I figured that was pretty reasonable.

Here’s how I put the thing together:

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Drill a hole in the PVC pipe with a spade bit. A 15/16″ or 1″ bit will work fine. Thread one of the male adapters into the pipe.
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Now you’ll need to fit the other threaded adapter into the tea kettle. Make sure your tea kettle has a round spout to simplify this task. Wal-Mart sells these ones for under $7 that work perfectly.
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We’re going to make a wooden bushing to fit the threaded male adapter into the tea kettle. The iron threads nicely into wood, and the wood will fit snugly into the spout to make a perfect seal.
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Choose a soft wood so the male adapter will thread into it without splitting. Here, I’m using a scrap of cypress. Turn it to the proper diameter to fit snugly into the tea kettle. A tiny bit of slop is OK, since the steam will make the wood expand anyway.
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Then put the cylinder in a chuck and use a 1″ Forstner to drill out the center.
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The bushing is made. Now I just have to cut it to size with a fine-toothed saw.
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A perfect fit. If you don’t have a lathe, you can probably do this by drilling the hole into a scrap of wood and carving around the hole until the bushing fits. Just stay away from plastic/rubber for your bushing – it will melt!

 

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Now just attach the PVC pipe to something sturdy (here I tied it to an old shavehorse) and hook everything up.  Fill the teapot with water and crank the hotplate up to HIGH.
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Soon, you should see steam billowing out the ends of your pipe. Now’s the time to put the plugs in. I ended up using a sponge on the far end and a cleanout cap on the near end. Best to have steam moving through the rig rather than plugging up both ends. You definitely do not want it to be air-tight. You’re trying to bend wood, not detonate PVC pipe.
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My crest rails were 3/4″ thick at their thickest point. General rule-of-thumb is to steam 1 hour per inch of thickness. I left them in the steamer for about 50-55 minutes and they bent like a stick of Juicy Fruit. Man, I love steam-bending!

A few things to keep in mind:

Ideally, you want your steam rig to be just big enough to contain the parts you’re trying to bend. I’ll be using my steambox for Windsor chair parts and maybe the occasional ladderback, so the 4″ PVC is a perfect size that should fit anything I want to throw at it. My first steambox was a 12″ x 12″ x 48″ plywood box that was really oversized for what I was using it for. No use heating more space than you have to.

Speaking of plywood, most steamboxes are built using plywood, which I suppose is better than PVC pipe. The pipe can actually melt at high heat. But PVC pipe is cheap, good plywood is expensive, and bad plywood won’t last very long. My hot plate is not powerful enough to melt the PVC, so I’m happy with it.

Finally, don’t let your steambox run out of water! I had about 2 cups left in the tea kettle after 55 minutes. I doubt I’ll ever have to steam anything more than an hour, so the tea kettle should work perfectly for me. You may need to size it up if you’re bending something much thicker than an inch.

Good luck, and get bent!

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