Steaming into 2011

I’ve spent the last couple of months in the studio (when I can spare some time from teaching) working out the kinks in my new steam-bending system. I decided last summer to change the material and process for the sculptural outdoor benches I’ve been making (with help from Chris, Yvonne and David) for the last few years. In keeping with my own manifesto, I decided to use only locally available, sustainably harvested material (as opposed to the Jarrah, that I love, but which I had shipped from Western Australia) and to use steam-bending rather than laminating to reduce the amount of waste byproduct and to avoid any chance of de-lamination of the benches in the rather extreme environment of the Napa Valley.

Steam-bending requires almost total control of the process of making from the milling of the lumber through to final assembly. For wood to be suitable it needs to be air-dried only to around 20% moisture content. Most commercially available lumber has been kiln dried to close to 8% moisture content and is difficult to bend. Then each board has its own strengths, weaknesses and inclinations so that total control of the final shape of each component is less reliable that when laminating. But this can be kind of interesting as the nature of the wood still comes through in the final form.

I managed to get the first fully successful steamed element formed just today on the last day of the year. I now have the process fairly well dialed in (I hope) and so I’m expecting that the steaming can become somewhat routine over the coming weeks. Like baking bread!

I’ll continue to post images as the first steam-bent bench comes together.

The 8ft steaming set-up. I can extend it to 20ft!

The redwood boards ready to steam.

The indigo color on the wood comes from the tannins in solution in the wood reacting with the iron of the machine beds as the moist boards are dimensioned. The thicknesser actually wrings water out of the boards! this will be sanded off before the boards are assembled finally.

2″x2″ boards of redwood ready to steam.

Board #1 in the bending jig. No back-strap required as it’s a pretty gentle bend.

In the image above you can see the pencil line on the jig to the right of the board. That’s where the board is expected to flex back to after it has dried completely in a few weeks.

Steam Bending. Cut to size, steam and bend! Nothing could be simpler!

HAPPY NEW YEAR!!!

9 Comments

  1. Looking good! I’m curious about the dimensioning of said boards, but we’ll talk later! Happy New Year

    Reply

  2. What a way to end 2010! Nice bend.
    I’m so glad you finally moved away from laminations. I kept thinking: “Donald would advise me NOT to use laminations for these harsh conditions, so why is he doing it himself?”.
    Happy baking and Happy New Year!

    Reply

    1. You shoulda spoken up and saved me some hassle!!
      Its been a long time since you were my student. Its time to share your experience with the old prof.

      Reply

  3. Nice looking set-up Donald. How are you making your steam?

    Reply

    1. I worked for a while to make a self replenishing steamer that could just crank out good steam pressure 24/7. But didn’t have much success. I finally opted for a simpler solution and now use standard wallpaper steamers (1 for the 8ft steamer, 2 when its extended). They get to pressure quickly (as measured by thermometers at the tube ends), and will generate a full head of steam for almost 2hours. Which is perfect for the thickness of the material I’m using. If I do another round (like today), I simply refill the steamer and restart it all. The tube retains a lot of heat so it gets back up to operating temperature again in about 20 minutes.

      Very nice in my studio in the cold and the rain. I need to start growing orchids in there as well!

      Reply

  4. hi donald
    i am not sure about the strap. sure you can bend it easily enough without one, but i suspect you may find you get a more reliable curve with a strap. it will produce less springback, which would otherwise vary more from board to board, depending on the grain.
    and we find that the wood keeps hotter if the water level is kept high in the boiler.
    it’s great fun though isn’t it?!
    david

    Reply

    1. Yes, it is an interesting process. Its a dance balancing so many variables.
      I’m nervous now that I’m starting to bend 16′ pieces that the time I loose in putting on a strap will allow the wood to cool too much before I bend it. Without the strap, I might have to re-bend some components because they either fail or subsequently flex back to much. Alternatively, it might be fairly straight forward to jig it up so that the piece goes into the strap at the same time as it goes into the jig. I’ll try both ways to test and I’ll keep you posted.
      I think David Colwell, will be joining us at CCA next year for a residency. I need him here now!!

      Reply

  5. if you set up the strap all ready to the right length before you put the wood in the steambox, you don’t really loose much time at all. and with the size of wood you are bending it won’t cool that quickly. steaming is a classic case of less haste more speed which all comes down to preparation! it is a bit of a choreographed dance like glass blowing which becomes fun to do and watch.
    i would love to catch up with david again . . .

    Reply

    1. David. Bending update.
      Yes, I think you’re right, the strap is a good idea. I’ve had to juggle the workshop again just to allow the strap to be deployed quickly. Its amazing what an inch here and and inch there can do. I agree that the free bends are pretty easy, but the results might be more consistent with the strap.
      Blog update coming when I score a good bend on my 16 footers!
      D

      Reply

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