Primitive Archer
Main Discussion Area => Bows => Topic started by: PatM on October 27, 2013, 11:25:39 pm
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Ipe/bamboo/sinew with spliced in Elm recurves. 50 inches t-t.
I just applied the sinew yesterday so it it will be a while before any bending takes place. You can faintly see the v splice under the fairly clear glue/sinew matrix. Other photos show handle area and mid-limb
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2878_zpsf8d0a7c0.jpg)
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2885_zps34e5f656.jpg)
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2883_zps0d199f5f.jpg)
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2875_zps75db1c09.jpg)
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Will sinew do anything over bamboo?
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What do you mean by "do"?
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I mean will it add performance and hold together?
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It would pull it into reflex and if applied very thin like he did it would add very little weight to the limbs
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I want to maximize drawlength which is why I used bamboo plus sinew. The sinew is actually thicker than it appears although it will shrink down quite a bit.
The bamboo already reflexes the bow and the sinew protects the bamboo and adds further reflex. I'm trying to store energy through the whole thickness.
Al of these materials are very heavy but the bow is very narrow so the strength of the materials should make them be efficient due to a thick cross section having greater potential energy storage IF the materials can take the strain.
The sinew is very thick over the handle and then tapers out to the base of the recurves.
Here's the handle/fade area.(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2877_zps3ff3e460.jpg)
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Ohh wow should have a gorgeous profile when complete
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I really like the look of this bow. Can't wait to see her finished. Gonna have a great full draw profile.
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Looks realy great. Ipe belly and sinew give great performance.Ipe is some horn substitute for me. Last time I make similar bow, but with bending recurve ipe/maple sinew. Only 38 lb at 28" shoot 270 yards with flight arrow. You can expect great results with 50 lb + draw weight. In classic composite with horn core wood is almost out of work. I experiment with ipe composite and I see that thickness of ipe should be not big , best results give 2-3 mm . It is strange but Ipe thickness have not big influence on draw weight, but give a lot of extra mass. I regulate draw weight in such coposite by middle layer wood thicknes and shape of bow
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Looks realy great. Ipe belly and sinew give great performance.Ipe is some horn substitute for me. Last time I make similar bow, but with bending recurve ipe/maple sinew. Only 38 lb at 28" shoot 270 yards with flight arrow. You can expect great results with 50 lb + draw weight. In classic composite with horn core wood is almost out of work. I experiment with ipe composite and I see that thickness of ipe should be not big , best results give 2-3 mm . It is strange but Ipe thickness have not big influence on draw weight, but give a lot of extra mass. I regulate draw weight in such coposite by middle layer wood thicknes and shape of bow
You should use maple for the core of composites, certainly nothing much more dense. Ipe has horrendous gluing properties for natural glues.....The Turks had it all figured out :)
PatM - yes the thicker the limb (all things being equal) the faster it will virbrate. Thick/narrow will outshoot wide/thin even if the cross sections are optimal for each wood. Frequency of vibration.
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I like the design very well, the only problem that might occur is adding sinew over bamboo, did you scuff up the bamboo? things don't like to stck to the surface. The fibers on bamboo are very sensitive to being violated by things like heavy sanding. Maybe th sinew will hold it all together. Looking forward to the results, should do well if it stays together.
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Interested in the results. Keep us posted.
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That's a really nice sinew job. I haven't any experience with sinew, in the picture it looks like the sinew is overlapping the joint between the ipe and bamboo, which I would protect the bamboo from splintering if it had been sanded. How thick is the sinew, did you make your glue, and what type did you use sinew, hide, or fish bladder. Can't wait to see the results thanks for sharing.
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The bamboo is sanded and scored longitudinally and acts as little more than a core that is holding some reflex. It should be well protected by the sinew. The sinew does just cover the edges but doesn't actually go around onto the Ipe.
The bamboo is also in two pieces with an overlay at the handle to cover the joint and then feathered out.
The Koreans use a bamboo core but they do flip it so the inside of the bamboo is on the back.
The glue is just Knox and the sinew was all put on in one go. Can't tell for sure the thickness at this point but I would say about 3/16 at the handle tapering out to the tips.
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Slightly better view of the v splice through the drying sinew/glue. Bamboo underlay on belly of v splice.
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2891_zps8a37ba39.jpg)
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_2889_zpsc1eae548.jpg)
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That's cool
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Cool project PatM.I like it.Your bow you could just tiller it out slowly as is like a self bow opposed to the horn bow construction with the tepeliks etc.I wonder about the over draw though.That'll be revealed in time.Lot of thought and concern done by you for this one.She'll make er.Look forward to looking at it finished.
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You realize Pat that if you were to compete with that bow it would have to be in the complex composite class. It should be interesting to see how it does.
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That is the idea ;)
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Thats a tough class but they do allow overdraws and special arrow rests. Pat, are you planning on making the flight shoots in 2014?
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Very curious to see how that puppy performs :)
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It seems unlikely that I'll get there but that won't stop this bow (or a refined version if it works out) from making it there.
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Pat Im Liking what I'm seeing :D keep up the good work!
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Flexing the bow until the handle touched the floor (with the tips also on the floor) resulted in the failure of the glueline between bamboo and Ipe on one limb.
The bow was glued up in a questionable temperature scenario last winter so I will try again in better conditions. I will likely use a continuous Ash backing strip this time since it seems to give a better glue joint.
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Bummer. What kind of glue did you use?
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Dang....I was looking forward to seeing that one all done.
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It was G2 Epoxy but I think the temperature in the shop dropped below the minimum requirement during the night and warming it after the fact does not seem to have rescued it.
Two bows glued up with the same glue but using Ash as a backing have held up fine. The temperature was not as iffy though.
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Heck of a good effort PatM.Oh well.I might be posting a thread in a couple of months of my Turk bow doing something similar but like you I have another ready to try again.Good Luck.
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Your probably better off to use TB3. I like G2 but it can be a bit touchy
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And you don't have to worry about heat curing TB3.
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very very cool