How much sinew?

[gfugal]

How much sinew in weight do you use when sinewing your bow? I'm trying to decide if I need to shred some more. I have 3.5 oz partially processed as of now.

[Stick Bender]

You have about 1500 grains there if my math is right, not knowing what bow your putting it on or how many layers your thinking makes it hard to answer , but 1500 grains is plenty for most sinew bow !

[simson]

That depends a lot of drawweight and length of the bow ...

[gfugal]

Ok here's what I found by going through older posts.

I am lucky enough to get elk leg sinews 20-25" long. Each leg sinew yields between 25 and 35 grams of processed sinew. between 1 and 3 will back a bow with perfect long 20+" bundles. I just finished backing a 47" bighorn bow. 3 applications over 3 weeks. 142.5 grams. Over 5 ounces on this bow. Some smaller deer leg tendons will only yield 5 grams or so -   loefflerchuck

So 25-105 g / 385-1620 grains / 0.9 - 3.7 oz

60 grams – mikekeswick

so 60 g / 925 grains /2.1 oz

I have heard it takes 16 [deer] legs - wood_bandit 99

So 1 leg = 5g (according to lofferchuck), 16 = 80 g / 1230 grains / 2.8 oz

About 10-12 decent length [deer?] back strap sinews will give you a solid 3 courses. - PEARL DRUMS

I'm assuming 10-12 back straps is similar to 16 leg, so similar to above

as suggested above,, about 400 grains on each limb should be enough,, you can weigh the deer tendons whole and get an idea how many it will take,, I have weighed the elk tendon whole and then processed it,, and it is close,, you loose a little to waste when you separate it to threads,, for best performance, you want least sinew to hold the most reflex,, 1 oz is about 420grains,, I guess you could put 2 oz on each limb on a bow that long,, but it does seem like alot,,, - Bradsmith 2010

So - 56 g / 875 grains / 2 oz

OK oak walker.I can usually get close to 400 ounces of usable sinew out of an elk tendon. All in all sinew is sinew No matter where it comes from I think.
Weighing it is the proper thing to do when it's ready to be put on. It's all relative here. On a 62" bow being sinewed 2 ounces per limb will be a whole lot. Never done that much.I know half that will do the job, or an ounce per limb. 4 ounces is at least 30#'s worth of draw & that's relative too. Don't know how much reflex you want. With that much you need a lot of reflex to make it work for it's money.Need more info to answer your question. – BowEd

Same as above

IMO no more than one light layer on a bow that long [66'] if you are set on doing it. If your bow gets too long the added weight of glue and sinew outweighs the benefits of adding it. A longer bow with a troublesome back would be better suited with a rawhide backing. If you want to add sinew for performance reasons only, I suggest a 58-62" tip to tip bow with 2-3 layers as Bryce suggested.. -  PEARL DRUMS

Deducing from the earlier quote from him I'm assuming 80 g / 1230 grains / 2.8 oz gives 3 courses. So 1 course would be 26 g / 410 grains, 0.93 oz.

When we say courses it means layers.  Most people apply sinew over the entire limb but I do not.  Many years ago I did some thinking on the subject matter and I deduced that it was not necessary to apply sinew that way.  What I started doing was to apply the sinew to maximize it's use plus keep the added mass as low as possible.  I figured that a limb does most of its tension work down the center where you have a crown and that the outer parts of a bows limbs do very little work.  I knew that sinew is more elastic than wood so it could stand to have a high crown.  What I therefore did was to apply no more than 1 course along the edge and the outer limbs.  Then moving were 2 courses progressing to 4 courses down the center of the limb.  This produced a higher crown, almost like a cable of sinew down the center of the limb.  All of the bows I sinew backed were short, highly reflexed static recurves and they all shot into the 180 fps with 10 GPP arrows using dacron strings.  I'm sure that with FF strings and a bit of tweaking of the design it would have been easy to shoot 190+.  Jeez, just talking about it makes me want to make one 

Just good advice, I have no guess on how much Mark uses haha.

[gfugal]

Surprisingly, all the values were very close together. It sounds like the consensus is around 2 oz give or take depending on circumstance. So I should have enough if I have 3.5 oz.

[gfugal]

Does Elk Sinew really give you 5 times as much sinew than a deer leg. That seems like a huge difference.

[Bryce]

That depends a lot of drawweight and length of the bow ...

Exactly. Depends entirely on the bow. Unfortunately there is no magic formulas

I just got done examining some museum pieces and it seems that the amount of sinew wasn't a preference according to nation or tripe/group.
It was more of a personal choice by the bowyer. Some bows within the same group depending on wood and design, some had nearly 1/3 the thickness was sinew and others only a single layer laid down. I'm sure some bowyers prefer more sinew on their yew than their Osage or plumb. And vice versa.

I've backed somewhere around 25-30 bows with sinew. And I prefer elk leg sinew over most. Moose sinew is really awesome as well but not something I'm allowed to hunt in my state.
And I'll judge the wood to determine the amount of sinew and things such as weight and draw factor in as well. I also don't sinew the entire limb. Especially the tips, not must strain out there no need to waste resources in that part of the bow.
Just dig in man! Start the process and feel out what feels right to you. Just make sure your gluenis good and hold nicely, not to thin. Like a warm syrup consistency. I highly recommend using a comb to lay down the sinew to the limb. Make a nice smooth straight matrix of sinew. You can wrap it up for a nicer smoother drying or leave it open and fill caps as you go, either way a good sinew job is worth the time and the effort. Allow proper drying time and you'll have a very nice bow that'll probably last you a lifetime.

[willie]

Greg
wouldn't the amount of sinew depend on how much you are designing the limb to bend?

[gfugal]

I wasn't necessarily looking for an exact number. More of a ballpark. Sure how much sinew you use is going to depend on the length, wood, design, poundage, etc. I just had no idea how much I should be looking at. 1 oz, 5 oz? to an experienced Bowyer who's sinewed a lot of bows they have an idea how much most bows take and can adjust accordingly. I didn't have that hence the post.

[osage outlaw]

This question gets asked a lot.  I always have the same answer.... More than you think.  Make sure you have plenty.  You don't want to get 3/4 of the way done and run out. 

[willie]

depend on the length, wood, design, poundage, etc

.

sooooo....

what kind of design do you have in the works?

[Stick Bender]

I have only made 3 sinew bows with 2 shooters 1 faliure do to belly isue self induced belly crack due to over reverse stringing they ranged from  900 grains to 1150 grains of sinew all in the 45-50 lb class & 57 in to 64 in. I weight all my sinew that I put on a bow for future reference, like Bryce said it's a mater of bowyer preference & what's trying to be achieved I find Elk & moose rear leg sinew the easiest to processe not all tendons are equal and you get varying amounts of sinew from each one it hasn't been my exsperience to get 5 times more sinew from Elk leg over White tail leg although you do get more but varies , prepping the back of the bow & glue used is important, this is a endless topic from glue to application a lot of varied opinions & ways to do it , also my bows gained draw weight after a year or so & in the winter months to , there is a fair learning curve with sinew but after your first you will have a good idea of the prsocesse and how to improve the next !

[gfugal]

What's the best ratio of water to dry hide glue if you want to reconstitute it? I was reading that for Knox that you use 1/4 cup for each package (which if a package is around 2 g like I was reading that is, then that makes it 3.3% concentration?) but I also read 35% for dried hide glue which is drastically differant from the 3% of knox. Why would they be so different?

[Bryce]

I don't know. I don't weigh my sinew. I shred what I think I'll need and use it. If I end up needing more then I'll shred more, no biggie.
No need to over think it. Lay a couple layers down and feel it out.
What are your bow dimensions? What are you looking to get out of sinew backing your bow?

[mikekeswick]

You want to size the back a couple of times with 10% glue then do the sinewing with 30% glue. That is 30% dried glue weight to 70% water weight. Don't go thicker, it is unnecessary.