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Thread: Steam bending in place

  1. #1
    Join Date
    May 2019
    Location
    Grafton, MA, USA
    Posts
    13

    Default Steam bending in place

    I apologize ahead of time but I did advanced search for “Louis Sauzedde steam“ and got lots of hits. The problem is that in the three I checked not one of these three words was present. I say that as an apology to those who will point out an exact thread where the following is discussed.

    This tip has to give thanks to Louis Sauzedde (Tips from a Shipwright) who showed something similar here. Louis is bending a piece “in situ” using a folded piece of construction plastic as an envelope with the edges taped together. (BTW: using those three words in a search of Youtube got me this video right away)

    We felt the tape might give way so we modified it here and used a flexible plastic shop vacuum hose. The problem with that was after bending 4 pieces the hose came apart. We felt that even though the hose self destructed the convenience was well worth it.

    First, you can steam part of the piece in place and flex it so you know when it is ready to bend. Second, you can slide the flex down and steam some more of the piece while you are clamping the first part (no rushing in from the steam box).

    So, we thought of using aluminum dryer vent hose like this. This kind of hose comes in all kinds of diameters and lengths. A common one is used as a flue liner for chimneys and is 10” in diameter and 40’ long.

  2. #2
    Join Date
    Feb 2006
    Location
    Brooklyn NY and Dover-Foxcroft ME
    Posts
    580

    Default Re: Steam bending in place

    I have found that the flexible plastic tubing sold for draining washing machines will stand up to the heat of steam. It looks like the pleated plastic vacuum cleaner hose often provided with shop vacs -- but it apparently is a different plastic (I don't know hat plastic it is and the wrapper did not say), and has not failed me the way vacuum cleaner hose has. The smaller diameter provided an ample flow of steam. I would think that for most uses, a 10" diameter hose would be much to big -- awkward to handle, and perhaps with so much surface area that it would cool the steam while in transit between boiler and wood to be steamed. (I had also tried automobile heater hose, but it was extremely stiff and very difficult to work with.)

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    cr s IMG_1516.jpg

    You may want to check out this link:

    http://forums.wcha.org/showthread.ph...NE-TUBE-part-1

  3. #3
    Join Date
    Nov 2004
    Location
    Port Townsend WA
    Posts
    12,495

    Default Re: Steam bending in place

    The main advantage of using a wooden steam box it that wood insulates the steam from rapid cooling and water will drain out of the low end of the box, if it is set on a slight slant. Also, if the bending stock is laid on transverse supports within the box it then does not sit in pooled water and become super saturated. Ribs done in this manner set faster and dry faster.
    Jay

  4. #4
    Join Date
    May 2019
    Location
    Grafton, MA, USA
    Posts
    13

    Default Re: Steam bending in place

    RE: 10" diameter
    Stupid for a canoe, silly for a 14' KDI and would probably cool before softening the wood fibers. However for these guys, just the ticket. Dryer hose for $10 will work for us.

  5. #5
    Join Date
    Apr 2007
    Location
    Cundys Harbor, Maine
    Posts
    825

    Default Re: Steam bending in place

    You want lay flat poly tubing. It is available on ebay.

  6. #6
    Join Date
    Feb 2006
    Location
    Brooklyn NY and Dover-Foxcroft ME
    Posts
    580

    Default Re: Steam bending in place

    Jay -- I agree that a steam box is preferable in many situations, especially for someone doing many bending jobs over time. But for bending very long stock, or for the amateur doing a one-off repair or build, the flexible tubing has considerable benefits. And compared to a wooden steam box, flexible tubing uses essentially no storage space, a significant issue for some of us.

  7. #7
    Join Date
    Nov 2004
    Location
    Port Townsend WA
    Posts
    12,495

    Default Re: Steam bending in place

    I confess that I am also guilty of using plastic drain line pipe for a quick job! That works well when one needs fast and simple! For a big job though I do like the long wooden box approach
    Jay

  8. #8
    Join Date
    Jun 2018
    Location
    Lake Odessa, Mi, USA
    Posts
    147

    Default Re: Steam bending in place

    What is the largest cross section have you guys have done this way? I have a large rub rail repair ahead of me which would be a triangular shaped section cut out of a 4x4

  9. #9
    Join Date
    May 2019
    Location
    Grafton, MA, USA
    Posts
    13

    Default Re: Steam bending in place

    RE: largest cross section
    Compared to you we are making model boats. The KDI is 14" long and the sheer clamp (rub rail is yet to come) is about 5/8" square. It definitely would not have made the canoe stern bend without steam but 4" square it is not! It only took about 20 minutes to steam. We used a wall paper steamer seen in the video here.

    So, the issue is scaling this technique up. First it will take more time, of course. There may be a lot of heat loss due to conduction out the thin aluminum walls, so it might need some insulation. The thin walls might be a little fragile for large stock and it might be easier to accidentally put a hole in the tube when fishing the piece into it. Those fragile walls might not take kindly to being pushed against the 4 x 4 to check to see if it is "done". You might notice we had to support the piece from outside, while heating. Perhaps others can think of problems that might occur when steaming a larger cross section in place.

  10. #10
    Join Date
    May 2019
    Location
    Grafton, MA, USA
    Posts
    13

    Default Re: Steam bending in place

    Here is another example of Louis Sauzedde doing this to a piece that is about 1 and 1/2" by about 3".

  11. #11
    Join Date
    May 2017
    Location
    Cumbria, UK
    Posts
    171

    Default Re: Steam bending in place

    I made my own tube using a polythene sheet from a builders merchant.
    Cut to size, folded over, laid on a plank and welded together using an electric iron.
    It is essential to have grease proof paper between the iron and the polythene and under the polythene to avoid a sticky mess !!!
    Ideally the tube will be in one length but if you need longer, weld the lengths together before forming the tube. I was not able to stick 4 layers together at the join, this left a gap at the join which I used for the nozzle from the wallpaper steamer.
    steam.jpg

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