Primitive Archer
Main Discussion Area => Bows => Topic started by: Dane on February 17, 2009, 11:48:20 am
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I've got a recurved hickory bow project I'm reducing the stave on right now. For those recurve masters here, when do you recommend proceeding with the bending process? During floor tillering, after floor tillering, initial tiller tree step, or when it is at low brace?
Thanks in advanced,
Dane
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Dane, I usually put the curves in at after floor tiller but also after other straightening has been done. You may also have to "adjust" a bit more after first stringing if things don't line up.
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Pat, thanks. That is what was floating in my mind.
Dane
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I like to bend mine before floor tiller ..but still fairly close to bending...tell ya why...first off I don't steam recurves ..I boil them...second I build only static recurves on self bows..a working recurve will just eventually pull out....so being that, I need a thicker bend to hold my curves..I boil then bend..you only got about 60 seconds to get that sucker bent..and make sure you use a belly backing strip of metal or something to help prevent pulling a splinter...my caul is a 65 degree bend..now that is pretty steep IMO...I boil about 35 minutes for every 1/4 inch...
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At floor tiller stage my tips can be 5/8"x5/8" mol. That is plenty enough to bend safely and I use dry heat with oil to protect the wood. I clamp the stave in the form and clamp the metal strapping tightly to the stave. Then, with the heat gun, I begin heating, first near the tip then back a bit until the weight of the bow begins pulling the bow down. Then I know it is ready to bend. I slowly bend the tips down, making adjustments as I go and when it is fully bent I clamp it down until tomorrow. I can do all of this before I could get a pot of water to boil.
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Pat and gutpile I believe you are both refering to bending osage, hickory won't respond like Osage.
Completely different ballgame with hickory or other whitewoods.
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Ah, Osage. None of that in Yooperland or in New England, alas.
How about it, Dana? At floor tiller stage? I'll be using a wooden form and clamps, or maybe rope, and steam. My Calphelon will do nicely, :)
Dane
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Dana ,Nope I am talking about hickory...I have used dry heat on hickory to take out a twist or induce reflex. or align my tips after recurving but not for a radical bend such as a recurve..I steamed once on hickory ..lifted a splinter...had to glue on some back up to stiffen the tip..the other end I boiled and it worked great no splinter...you are right hickory won't respond like osage with dry heat on a radical bend but it responds even better than osage on tempering and either or does great with the boiling method provided above...ONE THING TO REMEMBER and no offense Pat..not stepping on your toes here ....do not rush any part of bow building.... if it takes a hour to get your tips boiled that is OK...either way I wait, dry heat or boiling you need to wait about a week to let the wood dry some or rehydrate some...before stringing..you can reduce your tips and realign but I wait before I put a string on..gut
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I was referring to osage. ;D But over the last few years I've used this method on other woods just not as easily.
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Thanks for the clarification gut and Pat :)
Dane I haven't done any radical bends, mostly just add a little reflex and flip the tips a bit for that dry heat works fine on all woods
at least it has for me :)
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In TBB II, Paul Comstock has a chapter(6) about bending wood and in chapter 7, Jim Hamm covers recurves. Both have lots of useful info and lots of pics with captions. I refer to it quite often.
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I have found I can't get the same degree of bend from dry heat as I can with steam or boiling. Dry heat scorches the outer wood before it gets hot enough all the way through to make any kind of sharp bends. This usually results in tearing of the wood fibers across the belly of the bow. I've gone to using steam for all my recurved tips. I ruined to many nice pieces of wood using the dry heat method. Dry heat is great for reflexing or "flipping" tips but I would suggest steam or boiling for a actual recurve.
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The recurves I have in mind are for a replica hickory NA Indian bow, a Mohaw bow to be specific. I'll floor tiller and then go with steam heat, and then make sure the moisture is gone before continuing work. Thanks for all the advice, Ryan, everyone else too.
Dane
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Dane, if you shellac the area to be steamed you can eliminate most of the moisture that will get into the wood. The heat and moisture shouldn't affect the shellac and you can remove it later with light scraping or sanding or wipe it off with alcohol.
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Now thats some good advice..got to try that Pat...especially since hickory is such a pain to get dry down south..any thing that helps keep it dry and work with water is a good deal for me...gut
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I generally induce recurves when the stave is brought to first brace. I find it easier to reflex the tips when there is less material. Like Ryan O, I prefer steam or boiling, as I have also ruined several nice staves with dry heat. I just ruined a nice yew stave by trying to recurve the tips with dry heat. One tip turned out OK, but the other cracked on the belly side. It's difficult with dry heat to get the wood heated completely through, without scorching the outside. The internal temp of the wood must be high enough to provide enough plasticity to make the wood bend without breaking. Dry heat works very well for tempering belly wood.
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Dane, if you shellac the area to be steamed you can eliminate most of the moisture that will get into the wood. The heat and moisture shouldn't affect the shellac and you can remove it later with light scraping or sanding or wipe it off with alcohol.
Pat, thanks, I recall that advice from elsewhere, and you reminded me of it.
I did some work on the stave after work today. Some honking big knots, but considering that the sapling bow held together, why not try with a knotty hickory stave? The wood works so well with a spokeshave and draw knife. Fun just reducing it. The other tool I really love right now is a small adz I have. Great little tool.
Dane
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I can get wood plenty hot with dry heat without scorching. Hot enough that gravity brings the bow down just with the bow's own weight. The reason I use oil with dry heat is to help hold the heat longer and help distribute the heat evenly...without scorching. If the wood begins to cool before I'm ready I just reheat.
Even though this method is quicker for me, I don't rush anything. When the wood is plastic enough to bend the wood will tell you.
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I tried putting a pretty radical curve on an osage bow recently and used oil on it. It lifted splinters on the belly even though I really took it slow and thought it should be thoroughly heated before bending. Keep in mind it was a good sized curve! I've flipped the tips on other osage bows using this same method in the past without any problem, but not as radical a curve.
I think I'll either steam or boil in the future when putting on large curves...probably steam with osage and boil with white wood.
Pat, Gary Davis uses the shellac method when steaming that you mentioned. He mostly works with osage....wonder if it would help any for boiling white wood?
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Maybe your heat guns a diferant tempature or something Pat. I've tryed it time and time again with mine with cooking oil ,crisco, olive oil, bear grease, you name it.....I still get the same results. Maybe a lower heat setting at a longer time would help? I've decided its just not much more work to steam them and the results are consistantly good for me so thats probally what I'm going to stick with. Good point about using some sort of finish on seasoned wood when you steam. I had a bow dry check on me once because I didnt do this. I now put a coat of poly on everything before I steam it.
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I read about the shellac from Dean Torges book, Hunting the Osage Bow.
The cool thing about what we all do here is there is no right or wrong way to go. What works for some may not work for others and vice versa. These are all suggestions that have worked for each of us and it is up to the new guys to take all the info, do a bit of experimentation and decide what works best for them. Without the experimentation, we'd all still be making bows just like the original TBBs and earlier books told us to do. Instead, we took the bow building ball and ran with it...and look at the bows that show up on BOM each month. There are lots of our past mentors that have big smiles because of the way we took the baton and improved on their previous work.
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it common after you steam to have checks appear? i steamed some reflex on a bow at the handle and had checks appear in the middle. i added super glue and wraped them but what caused it?
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What causes the checks is adding moisture to a dry stave(swelling it) and when it dries the wood shrinks causing checks. By coating with shellac or other sealants that can handle the moisture and heat, you prevent the moisture from entering the wood in the first place.
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Good stuff! ;D
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This is good stuff. I'm glad I asked this question to start this discussion.
I just reread the chapter on recurving in TBB Vol. II. No mention (I think) was made of sealing tips before steaming / boiling. Cool to see techniques and methods evolving almost before our eyes.
Thanks everyone.
Dane
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Pat,
You've just got to show a pictorial on how you dry head and use the metal banding at the same time. I just cannot get me mind around that idea. Seems like the band would get in the way while heating. Or do you just use the band after the wood is hot? You have that method down "Pat" and I would love to learn it from you.
I did try steaming my osage stave for about an hour with no results. Then I used the heat gun but it took a long time for it to start to bend, needed help to bend as needed, and then I had to work out the splinters on the belly. The osage took a lot of work but it doesn't take as much wood to hold the bend in a static.
On a subsequent hickory stave 3/4" thick it steamed for an hour + and took a great bend right off. This was with my 60 degree recruve jig.
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Christopher, next time I bend tips I'll take some pics.