Primitive Archer
Main Discussion Area => Bows => Topic started by: cool_98_555 on December 09, 2018, 11:06:16 am
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Hi guys,
I have a few questions regarding sinew. I've never tried applying sinew before, but always wanted to try it. I have an osage bow that is 64" long, stiff handle, and 1 1/4" at the fades with a straight taper to 3/8" tips. If I am using back sinew, how many do I need for this bow? I have been told 8 or 9, but I wanted to ask all of you. Also, on this type of bow, is 2 or 3 layers even necessary? Can I get away with 1 or would you recommend 2 or 3? And lastly, is there a type of glue that works best or can I use something like titebond 3?
Sorry for the many questions here, but I just want to be sure. Here are the questions in numbered format if you like that better. Thanks for the help guys!
Bow: 64" ttt, 1 1/4" at fades with a straight taper to 3/8" tips. Draw length is 29".
1) How many back sinews do I need for this bow?
2) Can I get away with 1 layer or do I need 2 or 3?
3) What type of glue is best? Would titebond 3 work and be just as good as liquid hide glue?
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For best results use hide glue. Not the tight bond hide glue, get some unflavored knox gelatin. It's cheap, easy to use, and works great.
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lots of varying opinions on the sinew bow, and really it depends on the desired result,,
sinew varys in size, so weighing it will give you a better idea on how much to put on,,
I will just tell you what I would do,,
since the bow is a little long,, I would put at least 3 layers so it will hold some reflex,, without the reflex it will shoot about like an average self bow and you probably wont gain anthing from the sinew,,its takes a bit of experience to learn how much sinew and reflex to put into a bow,, in theory a 64 inch sinew bow would draw,,32 inches,, with proper tiller your bow could shoot well,, but it is a bit overbuilt " in theory,,
I would use hide glue, i have used knok will success as well, there are guys here that will chime in,, with great suggestions and info,, (-P
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Thanks for the replies already. I can cut it shorter to 60" or 62" and brace it backwards while I apply the sinew. Would that do the sinew justice? For weight, lets say 3oz. Would that be enough for 2 layers?
Regarding the length being a little long....I should also mention that the bow is pulling 90# at 29" right now. The high draw weight would stress the sinew enough even with 64", correct? Thanks for the input guys.
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yes I think at 90#,, the 64 inches is fine,, but it will still need reflex,, I made a 80# sinew bow with no reflex,, and it shot well,, just slow,,for its draw weight,, between 2 and 3 ounces should be fine,,
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Brad if I were to brace it backwards how many inches of reflex would you recommend? I don't want to lose any performance....if anything I want the sinew to add performance and retain the reflex put in.
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have you shot it through a chrono at the present state,,
are you going to tiller it back to 90# or go with the increase in draw weight,,
I am spit balling ,, you will need to pull it to 5 or 6 inches of reflex,, and some of that will pull out,,,there is really no exact formula,,sometimes you do your best,, and just get what you get, no gaurantee,, but I think you are in the ball park,,,since the bow is already shot in,, an increase in performance may not happen,pound per pound,,,, except,, the added draw weight should give you more cast than you are getting now,,with same weight arrow,,
also,, since the bow is shot in and maybe has some string follow, I would be very gentle about pulling it into reflex,, I would probably gently heat the belly and very slowly induce the reflex,,or slowly pull it into reflex as the sinew is curing over a few days,,
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Yes I have shot it though the chrono already. I will probably go with the increase in draw weight, not bring it back down to 90, unless I have to really fix the tiller.
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Be careful when reverse stringing I have had belly stress cracks before getting to aggressive reverse stringing ! The limbs need to be pretty thin for 6" but at 64" you probably be ok !
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and what is the bow shooting now, so I can get an idea of possible increase in cast
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670gr arrow at 190fps, 880gr arrow at 168fps
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Why are you sinewing it?
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There is a very tiny crack perpendicular to the grain (1/16” wide) on the back of one limb and instead of putting a patch i want to sinew the entire bow. I really like this bow.
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If your mostly trying to protect the back perhaps you should consider rawhide? How deep is the crack?
When I use sinew it's cause I've got a short stave of wood that's a good match for it. I know a lot of guys like the sinew/osage combo, but IMHO there are many woods that match better. Osage is just awesome on it's own. )P(
If you decide to go with sinew, you won't need a lot to take the stress off the back. :)
Wishing you the best! :)
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Crack is barely noticeable. Extremely shallow but i want to ensure this is protected for the long haul
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this is an interesting project,, cause you are in a grey area,, where results are difficult to predict,,,,that being said, I sinewed alot of bows just to see what it would do and learn about the process,, that is enough in itself I thihk,,
I am out on a limb spitballing, but I think you will gain at leat 20# draw weight, and that will add about 20 fps at the increase draw,,I dont think the bow gonna shoot much harder at 10ggp than it is now, but it could,,depending on retained reflex,,
I dont think much tiller will be needed,, let the bow stabalize before scraping wood as the sinew will take a while to stretch,, I would leave it braced hours at a time for a few days,, before taking off any wood,,
dont worry aboug making it shorter, if you get it shooting nice, and want to shorten it later you can,, with the sinew on there you could go easy to 60 inches,,
good luck on your project,, keep detailed notes on your procedure so you know what you want to do the same and differently on your next one,,,, (f)
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Thanks for the replies. I've got my sinew, just need to get my glue. Would 4oz of glue be enough for one bow at 2 layers?
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yes
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dont buy the bottle hide glue..use the powder double boiler... hide glue and sinew are like peas and carrots..go very well together..hide glues slow dry time allows sinew to shrink properly for the best application for dry time... the only way to let sinew do its job properly IMO... you can always cover with snake skin or after dries size with tite bond... to waterproof... size bow before applying sinew and wring out sinew good before applying..if you use too much glue when to brace bow you will have a heart attack ... why?... cause all the cracking and popping of the excess glue will sound like bow is going to explode.lol...gut
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If you just need a little protection, then you only need a single thin layer of sinew and terminate it before the tips. No reason to bulk it up with a bunch of added weight unless you want added weight.
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UPDATE: Well I applied 2 layers of sinew with the powdered hide glue. I didn't soak the bundles in the glue before applying, but instead used a brush to just brush a layer of glue on both sides of the bundle. I don't think this was overkill with the glue. I came up with this awesome method to heat up the glue that didn't even require a glue pot. Anyway, I was trying to figure out how to put reflex in it while applying the sinew, since I was having a difficult time reverse-bracing the bow. I just elevated the tips on two chairs, then tied the handle to a 20# box of cat litter...this worked like a charm! Started out with 2.5" of reflex before the sinew, and already overnight it has improved to 3"! It's not rock-hard yet but i'm wondering how long I need to have it in the induced-reflex state before I just take it off and let it sit on its own for a month. I'm not going to mess with the tiller for a month but I want to be sure I take it off of my "reflex form" at the right time. Any ideas? 3 days maybe before I just let it sit on its own?
Funny story too...I was setting my glue station up in the house when my wife walked by and asked "what are you doing?" I just told her I was applying sinew to a bow, and that it's tendons from a deer that are shredded up. Thought she was going to send me out to the garage but she said "Can I help?" I had her prepare some wet sinew bundles for me...cut my time in half in applying it! She's a keeper I think ;)
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Nothing like an extra set of hands while adding sinew to a bow. I've always thought it would be helpful. ;D :OK
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That's awesome. I love my wife, but she'd never offer to help w/ sinew. I think she's a keeper for sure! (-S
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I think leave it for a week,, (f)