Author Topic: Osage recurve selfbow-Crack in the back!  (Read 16708 times)

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Offline VanceMan

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Re: Osage recurve selfbow-Crack in the back!
« Reply #30 on: July 06, 2015, 04:57:13 pm »
Here is a picture of the bow now. I will most likely sinew tonight if there are no more issues.

Offline Willibow

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Re: Osage recurve selfbow-Crack in the back!
« Reply #31 on: July 06, 2015, 06:16:24 pm »
In my admittedly very limited experience, backing a crack doesn't save the bow. In my case, it was rawhide over a crack, and I think it made the failure even more violent and dangerous. Luckily it failed on the tillering tree when pulled to 25" at 50#.  Had I been holding it, it could have gone badly. I think the rawhide held things together much longer than normally would have happened, and when it failed the energy stored made for a spectacular explosion. About a foot of limb almost stuck in the drywall of my garage ceiling.

Be very careful if you go forward with this bow!
Lord, grant me the courage to attempt this bow build.
The strength to pull it to full draw.
And the wisdom to listen to the wood.
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Offline VanceMan

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Re: Osage recurve selfbow-Crack in the back!
« Reply #32 on: July 06, 2015, 06:33:56 pm »
Thanks for the warning! From what I have researched in books, sinew is much more effective at providing a good backing so I think I will be better off than with rawhide.. but I will still be cautious! The only reason I am worried is that knowledge found in books is not always unbiased and is not necessarily the whole story so I'm looking for lots of personal experiences to draw from on this matter...thanks for sharing!

Offline bradsmith2010

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Re: Osage recurve selfbow-Crack in the back!
« Reply #33 on: July 06, 2015, 07:40:51 pm »
if the crack is gone,, then that is not an issue,, if you sinew back you have a chance to make the bow,, but I think the tiller will be pretty tricky cause of the reflex,, but if you get the taper even it should work,, if it was my bow I would give it a try,, and not think I was wasting my time,, even the most perfect design and wood can have hidden flaws effecting the outcome,, it would be easier to tiller with recurves a little smaller,,,, I think the cracks were from a little too much heat,,, but just guessing,, give it a try,,

Offline Dances with squirrels

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Re: Osage recurve selfbow-Crack in the back!
« Reply #34 on: July 06, 2015, 08:20:36 pm »
If I chose to try and save it, I would sinew it, BUT, I would put 3 courses of sinew on it. I think a small patch and 3 courses of sinew would fix the weak spot and allow you to make weight.

I made a straight standing snakey osage selfbow once and shot it for several weeks when it lifted a splinter by a cluster of pin knots. I superglued the splinter down, roughed up the entire back and then put a sinew patch, about 2 1/2" long over the area and then layed down 3 courses of sinew over the entire back, then diamondback skins, and I have shot it and hunted with it for many years. It's one of my favorite bows and I trust it completely. Sinew is better than rawhide when it comes to repairs like this. Rawhide is more for protection/preventive maintenance... before anything bad happens.

One other thing to consider... you have a LOT of recurve in that bow already, which can make it tough to tiller and maintain alignment. If you put sinew on it, as it dries, the sinew can shrink and try to pull it into even more reflex, especially with the limbs so thin... so measure it beforehand and as it dries, and if it starts moving too much, strap it  down or exorcise it or something :)
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Offline Marc St Louis

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Re: Osage recurve selfbow-Crack in the back!
« Reply #35 on: July 06, 2015, 08:42:22 pm »
A sinew patch I put on an Elm static recurve 10 years ago after the bow developed a crack on the back during hunting season.  It's still shooting
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Offline VanceMan

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Re: Osage recurve selfbow-Crack in the back!
« Reply #36 on: July 06, 2015, 10:25:36 pm »
If I chose to try and save it, I would sinew it, BUT, I would put 3 courses of sinew on it. I think a small patch and 3 courses of sinew would fix the weak spot and allow you to make weight.

I made a straight standing snakey osage selfbow once and shot it for several weeks when it lifted a splinter by a cluster of pin knots. I superglued the splinter down, roughed up the entire back and then put a sinew patch, about 2 1/2" long over the area and then layed down 3 courses of sinew over the entire back, then diamondback skins, and I have shot it and hunted with it for many years. It's one of my favorite bows and I trust it completely. Sinew is better than rawhide when it comes to repairs like this. Rawhide is more for protection/preventive maintenance... before anything bad happens.

One other thing to consider... you have a LOT of recurve in that bow already, which can make it tough to tiller and maintain alignment. If you put sinew on it, as it dries, the sinew can shrink and try to pull it into even more reflex, especially with the limbs so thin... so measure it beforehand and as it dries, and if it starts moving too much, strap it  down or exorcise it or something :)

Thanks for all the input guys! And yeah Im guessing im going to see some massive reflex due to the sinew, so I was planning on doing 2 courses.  But you think I should do a patch? Ive never had to do one before, how is it done and how much? Should it go under the sinew backing or over? Thanks!

Offline VanceMan

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Re: Osage recurve selfbow-Crack in the back!
« Reply #37 on: July 06, 2015, 10:26:41 pm »
A sinew patch I put on an Elm static recurve 10 years ago after the bow developed a crack on the back during hunting season.  It's still shooting

How much sinew did you use for that patch and was the crack in your bow somewhat like mine?

Offline PatM

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Re: Osage recurve selfbow-Crack in the back!
« Reply #38 on: July 06, 2015, 10:51:56 pm »
My question was directed at those saying the bow needed to be designed for sinew in the first place to make it worthwhile doing. What about this design makes it a poor candidate?

Offline VanceMan

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Re: Osage recurve selfbow-Crack in the back!
« Reply #39 on: July 07, 2015, 12:16:17 am »
My question was directed at those saying the bow needed to be designed for sinew in the first place to make it worthwhile doing. What about this design makes it a poor candidate?

Well nothing as far as I know.  It seems to be the perfect candidate to me...compromised growth ring, needs sinew to bring it to 28" draw, and extra protection for the highly stressed recurve. Sinew sounds like a good idear to me  ;D

Offline osage outlaw

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Re: Osage recurve selfbow-Crack in the back!
« Reply #40 on: July 07, 2015, 12:59:48 am »
My question was directed at those saying the bow needed to be designed for sinew in the first place to make it worthwhile doing. What about this design makes it a poor candidate?


Nothing except for the crack across the back of the limb.  The crack is why I wouldn't sinew back it, not the shape or design.  Me personally, I won't sinew back a bow with a flaw like that.  Yes it will probably hold and shoot fine but there is a chance that whatever caused it to crack in the first place will cause it to fail again.  If I find something like that in a bow I'm working on its going in the burn pile and I'm starting on something new.  I'm not much into patching problems. 

When I said "if I'm going to sinew back a bow it is going to be designed and planned for sinew from the very beginning", that included having a clean growth ring on the back.  It had nothing to do with the design of his bow.  I never said his bow wasn't a good design for it. 
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Re: Osage recurve selfbow-Crack in the back!
« Reply #41 on: July 07, 2015, 10:46:21 am »
I side with the I wouldn't put time into sinewing it because its shown you a flaw in it and has been compromised already....but to each his own... plus I'm not much of a fan of sinewing either in lots of cases. But that's just me. Either way if ya do or don't youll find out what you like best,and what works best for you,and you will develop ur own opinion after ya make some more bows.

Offline Pappy

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Re: Osage recurve selfbow-Crack in the back!
« Reply #42 on: July 07, 2015, 11:04:39 am »
I'm with Clint and Chris, but again that is just me, I will make a wrap or some minor repairs and might even do some preventive work on one I think could give trouble but after I get something like that in the back in a high stress area, a splinter raising is one thing, a crack across the back is another IMO. I'd cook brats with it. ;) :) Good luck, hope it works out for ya. :)
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Offline Badger

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Re: Osage recurve selfbow-Crack in the back!
« Reply #43 on: July 07, 2015, 11:07:49 am »
   Do you have any idea how strong the bow is now? You said you had it braced but gave no indication of its present draw weight. As thin as those rings are you might get away with taking it down one more ring. If it came in just a tad light you might even shorten up your hooks a little bit, those long hooks can be hard to deal with anyway.

Offline VanceMan

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Re: Osage recurve selfbow-Crack in the back!
« Reply #44 on: July 07, 2015, 03:19:46 pm »
I think I mentioned earlier the draw weight...i only ever pulled it out to 22" because it can't handle any more than that without sinew..and it seemed to be around low 30's#

Probably low 40's at 28"