Primitive Archer
Main Discussion Area => Bows => Topic started by: barebo on February 16, 2010, 10:08:45 pm
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I'm at tiller stage on a Hickory backed Ipe longbow. Last night I had it on the long string and was exercising the limbs between scrapes when -- YIKES !!! The bow comes flying off, and the riser / handle is cleanly separated from it. I used TB3 to glue the backing on, but I think that I goofed using 2 part epoxy to glue the handle on. The handle is Osage with Zebra on top. Does Ipe
reject or repel epoxy?? I sanded and made sure to mate the pieces well, and then used TB3 on the bow and Osage and clamped it overnight. Well......tiller resumed tonight and really starting to get a nice bend and I hear crackle - crackle - SNAP !!! Darn thing comes off again!!! Anyone have any advice here ??? What causes the handle to pop off ?? The bow is 70" ntn and the handle is only 6" long ???
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my understanding is that the ipe was probably oily and that messes with the epoxy more than the TB3. My guess, as i have nothing to prove that or no experience, just what i have heard.
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The wood near the handle is bending too much. Doesn't matter how strong the glue is if the wood under the riser is bending. My thoughts anyway...good luck.
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I agree with Nate. Did you use a power lam between the hickory and the ipe?
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Your handle is trying to bend because the core is too thin in that area. You may be able to salvage it by using a 1/8" thick lamination between the core and the handle.
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I started out with 3/4" x 1-1/4" Ipe. Then I added 3/4" Osage and 3/8" Zebra for a grip. Last one I did only had 3/4" glued to the Ipe, and held up fine. I actually only added the 3/8" Zebra for contrast. The Zebra and Osage are rock solid - the joint failure is between Ipe and Osage?? Got a nice glue up of the Hickory backing, and my tips are Zebrawood also - I'm actually 3/4 of the way to short string -maybe already there. Right now I've got a bend in the handle special !!! Floor tiller is great. I want the handle on???
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Overnight glue set up? Not getting enough time for the glue to set up? Just a thought :-\... 'm New at this and making my first board bow. ;)
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A 3/4" core at the handle should have worked fine - I don't know why your handles are failing then.
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Pictures are the best way to get help. My guess is that you nave narrowed the handle enough that it is bending. Even the weakest of glues would hold if there is no force on it to pop it off. The only force on a riser is bending in the riser.
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Do you have any pics of it on the tree? I don't think the handle will pop off unless it is bending there. I would glue it on using the 1/8 piece of wood between the riser and bow as Gordon suggested. Let it sit a few days then wrap it in the middle of the riser TIGHTLY with some non-stretchy string like hemp. then try to get the bend away from the fades... I hope it holds for you! :) -josh
edit: guess me and Justin were typing at the same time, LOL
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O.K. - here's my brainstorm - I'm going to use my Dremel tool with the small round cutting bit, and make a cross hatch pattern about 1/8" deep in both the Osage and the Ipe core. I'm going to then use the Probond glue that expands and hopefully that will hold??
I kept my limb width until 10" from the tips, and then tapered to the tips, so I'm also going back to mid limb and starting the taper there. That should get the mid to outer limbs bending more and relieve the strain near the fades (I HOPE!!!). We'll see.
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Epoxy works best with a rough or grooved gluing surface (unlike TB,) but I don't know if I would go so far as to take a Dremel to it-roughing it up with a hacksaw blade or some such then degreasing it good usually works pretty well. Maybe your outer limbs have been so stiff that the handle is still bending a bit.
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Barebow, did you clean the glue joint with acetone or alcohol, before applying the glue?
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I would mount a coarse jigsaw blade in a vice and drag both surfaces you want to glue across the jigsaw blade. Poor mans toothing plane. 1/16" deep groves should give it enough tooth to hold. Before you groove it get the old glue off both surfaces with 40 grit and after you groove scrub the surfaces with acetone. If your bow is bending and your handle is not the joint will fail. Every bow teaches something to the maker.
I use Urac and with the above grooving technique have never had a handle pop off. There's always the next bow though. Good luck
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I'm a gonna save 'er Grunt - paid a premium for the Ipe and the Hickory backing strip weren't free!! Not to mention that my Osage is getting scarce, and that Zebrawood was one of 2 bookmatched knife scales. I already thinned the limb profile, and am going to shave the belly on this puppy till it surrenders. The last Ipe longbow I made is close to 70#@28" -- I wanted this one around 50#.
I think that I was trying to get the near fades moving more, but I don't agree that it's the greatest tiller for a longbow anyhow. By the time I get the outer 1/2 of the limbs moving more, I hope I'll be o.k.
Lombard -- I confess that I didn't wipe it down. I guess that I might be my own worst enemy at that!!??
It's glued and clamped - we'll see what tomorrow brings.................??
Thanks for the input everyone - appreciated.