Primitive Archer
Main Discussion Area => Bows => Topic started by: JackCrafty on March 12, 2010, 09:35:07 pm
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Hi guys...it's been a while since I last posted but I'm getting back into shooting again.
A couple weeks back I was exercising a bow (and working on my pinch grip) and heard a very slight crackling sound. I thought it was the wood. I looked the bow over very carefully. It looked fine so I pulled back a few more times and heard the sound again. I said to myself "what the heck is that?.....", then SNAP! The string broke!
I think the dry winter air here in West Texas caused the sinew to dry out and become brittle. What do you guys think?
The bow is hophornbeam and the string is fairly new...only shot the bow with this string about 50 times. The bow is 45 lbs draw @20". The string is made of elk leg tendon and is about 1/8" in diameter.
(http://i246.photobucket.com/albums/gg112/jackcrafty/03-12-10/DSC_1510.jpg)
(http://i246.photobucket.com/albums/gg112/jackcrafty/03-12-10/DSC_1511.jpg)
(http://i246.photobucket.com/albums/gg112/jackcrafty/03-12-10/DSC_1512.jpg)
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I say...you are lucky that the Bow is in One piece!! I have had nothing but Bad Luck with Sinew Strings here...to damned Dry...I have started to make Rawhide Strings...and then I always make a B-50 String for normal every day shooting....Sinew and Rawhide won't last but a Hundred Shots here in this dry climate....JMO
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Yeah, the dryness is a blessing and a curse.
I've tried a couple rawhide strings and they broke as well. This is the first sinew string that I've broken on a bow, however. My other strings seem to be fine but I won't push my luck. I'll wait for a more humid day to shoot next time.
Perhaps the string was a little thin at that point? Now that I've looked at the pictures again I can see that the string above the break is quite thin. It's difficult to get the strings a uniform diameter.
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I had that happen before, I just figured it was cause I didn't have enough overlap in the twist. Coola bow, Crafty.
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That does get your attention. Looks like you had enough overlap. I had a hemp string go at full draw. No more hemp. I never made a sinew string. From what I have read its rain that works to harm a sinew string but I don't know. Jawge
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I've never used sinew, but artifical sinew works (unless you are truely a purist). It will stretch a little at first, but its strong and pretty much weather proof.
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Can you rehydrate a sinew string. Maybe store it in the bathroom for a few days. A little shower mist seems like it would help.
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On of the hazards I guess. Too bad about the string but good glad the bow took it. I have only made one sinue string and from your buildalong, thanks for the buildalong aan glad you are back. Hard to say why it failed, I don't think the lack of humidity should weaken it, but maybe just a weak spot. I waxed mine with bow string wax, maybe it is the indivigual strands wearing on each other, looks like yous was dry. I want to make another one but will use it on a light bow. Kenneth
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Your String broke at the point where strings should be reinforced---two or three inches from the nock. I don't understand it well, but Tim Baker describes it TTB 2 . It has happened to me!
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I don't know if you're supposed to, but I oiled the crap out of mine, more for waterproofing than anything, with the same oil/wax mix I use on the bow. I shot a couple hundred shots with it in CA (Mojavi Desert) before moving back to NY.
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Jude, I've never oiled mine but I think the oil will not make much difference for waterproofing. Try getting it wet and let us know how it works. I've made a string out of some pretty oily backstrap sinew and it's still holding up well. Haven't got it wet...yet.
Orcbow, yeah, there are high stresses near the bow tips. Good advice.
Little John, yes, it was probably a weak spot. I'm going to use the remainder of the string on a smaller kids bow.
Eddie, yeah, warm water vapor should rehydrate the string. I'll have to try that.
George, I've also read the stories about NA's not fighting in the rain because of the effect of water on he strings....
Thanks Bowkee, glad you like the bow. I've had it for years now and shot it quite a bit. HHB is really tough! I had to wrap one of the tips (I think you can see the thread wrapping in one of the pics) because a splinter popped up after shooting it in. Still shoots great.
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Hrothgar, I used to make all my strings out of artificial sinew when I first started this "primitive" thing. I agree, it works well. Much heavier than the real stuff though.
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Who knows what happened there? I have only had 1 sinew string out of about 25 break.( Besides from over use). I did a poor job making it. I splice 1 small thread at a time so there all staggered. It takes a long time to make a good sinew string. Yours looks to have been well made.
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Patrick
I know how you make your strings, they are really well made. It must have been a humidity problem. I have the opposite humidity problem here. ;)
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Isn't artificial sinew just sinew colored B50? ???
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Isn't artificial sinew just sinew colored B50? ???
Nope artifiacal sinew is nylon and super stretchy, B-50 is Dacron and medium stretchy :)
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On that subject, I just use brown B-50 and brown serving string. :)
I was wondering though, do you all dry twist your sinew strings. I wet twisted the one I made, and it didn't look nearly as white and fluffy as the one in the pictures when it was dry. It was about a quarter inch thick when it was wet, and dried to 1/8. I dried it with the loop over a dowel, and a weight clamped to the other end. When dry, it was hard and yellow, then I sanded the rough fuzz off of it.
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Jude, I "dry twist" my strings but I dip my fingertips in water while I twist. I can't seem to make a good string if the sinew is soaking wet. I wet the string after it is twisted, remove the excess water, and then hang it up to dry.
I have a thread call "Sinew Bowstring Technique" that shows how I do it: http://www.primitivearcher.com/smf/index.php/topic,5126.0.html
(Sorry about the low quality of the pictures. They are a little blurry...I need to take clearer pictures and re-post the thread...someday)
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I'm with jude. Dry twisting sinew is a modern method. Wet twisting activates the natural sinew glue and makes a stringer string