Primitive Archer
Main Discussion Area => Bows => Topic started by: FilipT on June 02, 2018, 03:30:35 pm
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I am writing this at the night so I cannot photograph the bow in question. Pictures tomorrow!
Anyway, I shaped 66" ntn longbow from the low diameter hazel stick. It is 31 x 21 mm in the cross section at the handle. Physical mass is 360 grams. My question is can I expect 50 pounds from this bow or I will get at maximum 30 or 40 when I finish tillering? Of course I am talking about ideal conditions and good tiller.
Also I am thinking about heat treating. Since this would be my first time doing that, I don't know how to do this. How far bow should stay away from heat gun, for how long, etc.?
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I've only used hazel(American) once with not so good results) so I can't help you with the weight you can expect.
For heat treating I hold the heat gun only an inch or 2 above the wood and work back and forth on a 6" area until it is brown then move out to the next 6" and so on out the limb. As I move out the limb I go back over the previous area(s). Once I've completed the limb I go over the whole limb again to re-heat it then let it rest over night.
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I don’t think, that 50# is realistic for a Hazel longbow with those dimensions.
This is my first bow - a Hazel ELB, 68” ntn, 30x32 mm at the handle. It took a lot of set (almost 3”), in spite of being toasted. And it has a draw weight of only 40# @ 30”. I’d say, Hazel is better suited for flat bows, but takes well to heat treatment.
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@PatB
Don't worry about the european hazel. I built 100# longbow last year that was initially even more than that! So you go twice over one limb? How about I do the whole belly and than again, instead of going two times on one half?
How long does it take for you to make these sections brown?
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@TorstenT
2" shorter bow in my case could increase the weight I think. 40# is not too bad, I would be pleased with that result. But I don't agree that hazel is better suited for flat bows. It has been used in history for warbows and we can certainly use it for low weight bend through handle bows.
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I do the one limb at a time to maintain the heat while tempering. The second pass is just to maintain the heat. Whether it matters or not I don't know.
The time and color depends on the wood used. Some woods like hickory brown up pretty quickly, some others take longer. It usually takes only a few minutes for each 6" section to achieve a good rich brown color. Some woods don't seem to get as brown as others. I guess the sugar content of the wood affects the coloration.
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Have you noticed correlation between depth of color and how draw weight increased? I mean what is the difference between lighter shade of brown and darker shade?
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FilipT
I’m just throwing this out there but I’m assuming that darker = more weight as long as it’s still wood instead of charcoal. The exact poundage gained might vary from piece to piece.
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If you don't have to remove much more wood you might make 50# with a bend through the handle design. The traditional elb uses a radiused belly. I doubt you have enough wood for that. I would start off going for 45# and if it starts taking set lower your expectations.
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I decided to not heat treat it today and instead I corrected the string alignment with steam. Tomorrow I'll try heat treating it.
@Badger
This is the bend through handle bow. You are probably right regarding poundage. I will aim for 40-ish and see what is going on. After all this bow will be for archery practice.
Overall profile
(https://s22.postimg.cc/x2g3fnhk1/image.jpg)
Belly around center area
(https://s22.postimg.cc/4ct7j1nup/image.jpg)
Picture showing 1,5" reflex
(https://s22.postimg.cc/yhho4gay9/image.jpg)
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I just finished with heat treating and here are the pictures. It seems that bow got a bit of reflex during the procedure but I might be wrong. Note: color is actually deeper than pictures might show.
(https://s15.postimg.cc/zbmz7w4uj/IMG_20180610_171954.jpg)
(https://s15.postimg.cc/l578co1p7/IMG_20180610_172005.jpg)
(https://s15.postimg.cc/pebyeucob/IMG_20180610_172017.jpg)
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Attempted to tiller it, it was pretty much impossible. One of the worst bending I have ever seen. Lower limb not moving at all and upper too much. As I corrected the lower one, weight of course, started to drop and at 20 inch or so of draw it barely had any power. Now it will become firewood.
Next.
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I suggest you do the tiller it at best of your skills and measure weight at the end
You may end up with a good bow or at least you'll pack some experience
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I'm not sure about the difference in hazels but the stuff we get here (UK) is very capable of #50 and more. It dries and is workable quickly but make sure it is properly dry (10%) before starting tillering.
I have made some thin design have very little set. I like to get them to 22" to 24" on a low brace (hopefully before I get any sign of set developing) and then I heat treat one limb at a time for the same amount of time (about 25-30 mins usually depending on bow length) until it's a nice toasty brown and too hot to touch for more than a nano second. You can introduce some reflex at this stage if you want. Then finish tillering carefully and it usually at least stands straight and tends to be pretty good at keeping it's shape too.
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Our hazel is also strong. Last year I made 100# bow out of it. Actually it was way over it until I carefully reduced the weight. This bow here was inch and a half in diameter sapling. Just couple of years old and that is why the initial name of this thread was "am I expecting too much" haha.
GlisGlis
I don't have any usage nor time for 20# bows. This bow rapidly approached being that weight at the end.
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.I don't have any usage nor time for 20# bows.
Wrong. That's how you learn. Nothing is harder than making a perfectly tillered 20lb bow. Making 100lb bows is easy, subtle wood removal makes very little difference and you have lots of room for error. Plus it's much harder to tell if a 100lb bow isn't perfectly balanced on the release or twists subtly in the hand or has excessive hand shock due to uneven tiller. If you scrape the wrong area with a 20lb bow then it becomes a useless stick before you can blink.
Unless you're a week away from losing your hands and vision and can literally only make one more bow, you've always got time for a learning experience. If you wanna throw it away when it's done that's fine, but get it done. I know far too many bowyers who can make a 140lb self bow but fail miserably if they're asked to make a bow for a kid.