Adventures in steam bending - boom gallows

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Adventures in steam bending - boom gallows

Postby slash2 on Thu Dec 22, 2022 5:22 pm

I know the manual says the gallows is optional, but that is followed by a list of reasons to have it. I agree. However, it seems a bit clunky to me, but the Pocketship is meant to built with a pretty small set of tools, so the design makes sense. Since I've been experimenting with steam bending, it occurred to me a 'hoop' gallows might be nice. I decided to make a semicircle, with straight legs at the ends, out of 1" x 4" white oak. I've been having decent success lately with steam bending (see my posts elsewhere), so I felt pretty confident. I built a form and planed the air-dried oak and eased the edges. In my first attempt I steamed the wood inside a corrugated drainage tube with some insulation added around it. This isn't an extreme bend but I thought it best to add a compression strap on the outer side, which I made out of 4" galvanized flashing and some aluminum angle. It started off well but my ratchet strap jammed up and I lost precious time. I didn't get the bend all the way in until after a half hour out of the steamer - not good. I also noticed part way into the bend that a section near the apex was not conforming to the mold; probably due to a weak spot in the wood, though I did not see any flaws. I pulled that in with clamps and let the thing sit overnight. ( Note: it seems most ‘professionals’ use a thicker strap. Although I’m confident my strap had sufficient tensile strength to keep the outer side from expanding, perhaps a thicker strap would help the wood conform to the mold. ) Next day, sure enough, I had about 9" spring back on each leg. I decided to re-steam it (though I've seen conflicting opinions on that). This time I decided to use the plastic bag method popularized by Lou Sauzedde on his totalboat YouTube channel. The nice thing about this method is you bring the wood up to steam but leave it in the bag and continue steaming as you bend it around the mold. I let it steam a good hour after the temperature inside the bag was up to 100 degrees C throughout. The process took an entire water fill of my Earlex steamer. This worked well:
Steam bag and mold
steambag.jpg (34.2 KiB) Viewed 256 times

I had very little spring back - an inch or so, but when I removed the board, I found a crack where I had the bulge from the first bend:
split.jpg (57.17 KiB) Viewed 259 times

Anyway, I decided to mount it to see how it looked. I realize it's about 5" to 9" too high from what I have read, but you can get the idea. The picture makes it looked a bit bowed out but the verticals are straight.
Hoop Galllows
gallows.jpg (127.13 KiB) Viewed 260 times

Obviously I'll need to add a seat for the boom and mast to sit in.

I'm curious to see if I'm missing something doing it this way. Will I bang my head into the curved part, or is there any other possible problem?

I do have a second piece of oak, and may try again to make a nicer piece. After all it's winter and I have time on my hands....
Last edited by slash2 on Wed Dec 28, 2022 9:46 pm, edited 1 time in total.
Posts: 87
Joined: Fri Jul 09, 2021 2:27 am

Re: Adventures in steam bending - boom gallows

Postby slash2 on Sat Dec 24, 2022 2:25 pm

I epoxied the split area down and, after it cured, sanded the whole piece. On close inspection I realized the grain makes a little wave right at the split:

Wavy grain at split
7A312088-174A-47D5-ABA6-3D1F1CE47B80.jpeg (59.84 KiB) Viewed 227 times

That explains the split; I had missed it on my initial examination of the wood. So, although steam bending is a bit of an art, some rules do seem to apply.
Steve Sawtelle
Posts: 87
Joined: Fri Jul 09, 2021 2:27 am

Re: Adventures in steam bending - boom gallows

Postby Hooky on Sat Dec 31, 2022 6:36 pm

Hey Steve, I love what you are doing with the Gallows, it adds a uniquely traditional style to the boat, I can’t wait to see the finished product.
Also thanks for sharing your steaming process, good tips for when I steam the gunwales.

Cheers mate
Terry from down under
Posts: 40
Joined: Sat Apr 30, 2016 5:49 am

Re: Adventures in steam bending - boom gallows

Postby slash2 on Sun Jan 01, 2023 6:55 am

Thanks for the feedback Terry.

I also can’t wait to see how it looks in context with the completed boat. If nothing else it will be unique.

Here’s a good, quick video of how Lou bends outwales:

A bit trickier on Pocketship as there’s nothing convenient to clamp to for the rub rails. But I guess one could screw the rail in right through the bag. Then after it cools pull the rail, remove the bag, and then epoxy the rail in place.

BTW, for my bags I used plastic tube bags used in food sealers- like Foodsaver. Widely available and reasonable cost.
Steve Sawtelle
Posts: 87
Joined: Fri Jul 09, 2021 2:27 am

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