Nettlesome Episode 6: Bending the Oak Frames
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- Опубликовано: 7 сен 2024
- This video on steam bending white oak boat frames is part of a series that follows the work of LaDale Winling in the building of a Haven 12 1/2 sailboat. The Haven is a daysailer designed by Joel White and is a centerboard adaptation of the Herreshoff 12 1/2. Winling is a novice sailor and neophyte woodworker taking on this challenging project from scratch.
For reference, I have drawn on Bob Emser's The Art of Boat Building (Season 2 Episode 8), Chuck Jenkins' Haven building series (Episode 4) and Maynard Bray's book How to Build the Haven 12 1/2. These are steps 77 to 83 from Bray's book. In addition, there are helpful articles on restoring Herreshoffs from Wooden Boat magazine, hosted by the Herreshoff Catalogue Raisonne, which help understand this process, the materials, and any challenges.
Jenkins Boat works:
• Haven 12 1/2 - Episode 4 ( • Steam bending oak ribs... )
The Art of Boat Building:
• S2-E8 Haven 12 1/2 - Building a Steam Box and Steam Bending Oak Frames: ( • Building a Steam Box a... )
Maynard Bray, How to Build the Haven 12 1/2 Footer: (www.woodenboat...)
WoodenBoat Mastering the Skills, Season 1 Episode 4, Steam Bending: (skills.woodenb...)
Off Center Harbor, Steam Bending Oak Frames: (www.offcenterh...)
See also Tips from a Shipwright's videos on frames ( • How to steam bend wood... ), grain orientation ( • Understanding wood gra... ), and the whole Remora restoration series.
Herreshoff Restoration Articles: Pt 1 (herreshoff.inf...) Pt 2 (herreshoff.inf...)
The green white oak came from Griffith Lumber in Floyd, VA (detailed in Episode 2). I cut the wood more or less solo, cutting the 16-foot boards down to about 60-65 inches, then cutting them to 7/8" x 7/8". This was a bit larger than the 13/16 x 13/16 in the plans, because I will probably have to plane these down a bit as I fair again.
I steamed with most success when I steamed no more than two frames in the steam pipe for an hour. One version of the advice says about an hour for an inch of thickness, but 45 minutes did not tend to be enough. With 42 frames steamed, I had 12 break at a total loss, a bit under 25 percent. I had about 4 break where I had a shorter, straighter mold handy (eg, 2, 3, 4, or 5), so I could salvage the good 2/3 of the broken but still flexible frame.
For equipment on the frames, I used a Craftsman 15 amp table saw and a Wagner Spraytech 700-series wallpaper steamer. The table saw was pretty much at the limit of its abilities with the white oak. I have been using a saw from the local nonprofit tool library, but I will have to find something more powerful (probably) for purchase.
The steamer is the key tool that made this manageable. Several builders rig up their own steamer with a propane tank and a burner and whatnot and that was not going to work for me. The steamer could produce enough steam for two frames in a smallish, 3-inch PVC pipe at a time, and I could fill up the reservoir and plug it in any afternoon with hardly any preparation, so long as the oak frames had been cut. The original steam box I made was way oversized for the steamer so things got much better when I bought the pvc. When handling the hot wood, I used some fairly standard work gloves with rubber-coated palms and fingers. They worked fine as long as I was careful at the moment I pulled the cap/rag off the steam pipe. If I had my druthers, I might have bought some more expensive waterproof leather gloves at the hardware store.
I "painted" the frames with boiled linseed oil available at Lowe's. The clamps were mostly Jorgenson 18" EZ-Hold bar clamps, with one Irwin 18" trigger clamp. The Irwin felt a bit more powerful but its clamp pads were a little smaller, which was less forgiving in the rapid process of clamping the frames down. I began with Simpson Strong-Tie A21Z angle brackets (about an 1/8" thick) for the bottoms of the molds, but they were not heavy duty enough, so I switched to ML23Z angle brackets (about 1/4" thick). For evening out saw marks on the frames I used hand chisels and a DeWalt palm sander; I bought a thickness planer after this step was done.
In the video I point out what you can do with 3 or 4 zip ties or clamps at key locations. However, it is true that the more clamps you have, the better your shape will be, with many control points.
Great job. Nice video. You will enjoy every step of the build.
Thank you!
Well done! Your wooden steamer looks very similar to mine. The Lawley requires both full length ribs and what I refer to as half ribs. The 8 footers went into the wooden steamer for at least half an hour. Although the longere half ribs went into the wooden steamer, most of them went into the hood end steamer which, for shorter pieces was quicker and more efficient, not to mention requiring less set up time. Like you, I used a Wagner wallpaper steamer for that.
By the time I was finished I had steamed over 30 ribs and half ribs with only one breakage. To avoid breakage, what I found worked well was that right out of the steamer I would pre-bend the wood over my knee, and in most cases twist it as well in order to get the wood to relax. I could actually feel it as it was happening. I could also guage how far I could bend it without breakage. With the wood now relaxed I could offer it up to the boat.
My frame and ribband situation is also different than yours so to get the rib into the boat. Mine was a two person job. As a riib or half rib was offered up to the boat, having pre-bent It, we would then over bend it slightly starting close to the keel, then continue over bending as we worked outward. With the wood relaxed the ribs seemed to lay into the required shape much easier with less tendancy to either break or spring back.
I have 4 half ribs that like you, will be installed once the boat is off the molds.
I offer this, not to hi jack you site but perhaps it might help someone else who might be considering building a boat such as this.
BTW I'm stealing your zip tie idea. I can see I will have use for that.
Good luck with the rest of your build.
Bending frames into an upright boat with ribbands (or in restoration) is intimidating! I might take that up in my next project, but I am super impressed in what you had accomplished in your last update, and totally understand about the need for a second person. Keep it up! I'd also like to see an image of an extant Lawley if you have any -- we saw the plans in your first video, but any photos of what they looked like finished?
Nice water lines.
great video. I'm glad you showed a couple of fails cause, that is just part of it! You're doing great! oh yeah, meant to ask. any family or friends, think you're crazy yet? lol
They thought that from the start! But when my daughter was getting a tour of a woodshop today, she saw a bandsaw and then bragged that I had one and that I was building a boat. That made me feel pretty proud. Will be prouder still when I get this launched.
Just a comment for information, not knocking your work...steam is a funny thing, your wallpaper steamer puts out steam but for bending timber you need HOT steam and a lot of it. Some people put all kinds of concoctions both on the timber and in their water but my old Dad used to say there was nothing better than really hot steam and plenty of it. I have bent 8 by 11 eauculiptus beams to a 6 foot radius before but that took a roaring fire in a 44 gallon drum firepot with a 13 gallon steam drum inserted partway in it. Tried 1 after 6 hours but it wouldn't go so they went in for another 2 hours! For dinghy work I use a 5 gallon drum over a 3 row propane burner. The steambox needs insulated in cold weather especially if there is any wind about. 3rd generation boatbuilder with dozens of boats built. Hope this is helpful to someone. I see a lot of u-tubers struggling because of not enough steam. Cheers
I appreciate this, Glenn, and after having done these, I think the key thing I could have done was add more steam and steam longer, just as you say. My calculations at the outset just didn't take into account the leakage and the wintry environment (I'm sure it would have been easier now in summer).
I steamed frames for a lapstrake boat with a friend a month or two afterwards and he had two wallpaper steamers for his box, which got the box up to temperature more quickly and kept it there better. Our experience with bending those frames for the lapstrake was much easier, with less breakage.
More steam, steam longer.
I love your communist red pizza oven in the back. Did you build it?
Ha! No, that one we ordered as a wedding present to ourselves.