Sinew backing a bow.......

[Jericho117]

Iv'e decided to back one of my longbows with sinew. The bows dimensions are 68' long, and about 1 and 1/4 of an inch thick, close to 1 1/2 inches wide, and tapers to about 3/4 of an inch near the "ears". Im using hide glue for the adhesive and pine pitch to cover the sinew. What I want to know is if it is ok to have just one layer of sinew on the back, and if it is ok if the sinew is only about 3/4 of an inch wide (the width of surface area on the back of the bow). I just thought this small amount of sinew would do little to improve the cast on my bow, what do you experienced bowyers think? My bow pulls 45 pounds at around 26 inch draw, and fires around 110 mph. My guess is the bow will pick up a few pounds, maybe 4 or 5, and increase speed to about 115 mph, I have no clue. Iv'e only backed my bows with rawhide. Any advice or correction of my calculations would be mighty helpful. Thanks.

[Jericho117]

If you want to know how the backing looks so far, go to my album entitled "more bows..." and you will see it in the pictures.

[FVR]

69" in my opinion is a little long for sinewing. Maybe 62" max. length, the mass of the sinew on the limb is contradicting the reason why you would sinew a bow.

If you want the bow to speed up, cut it down to 60" and re tiller to the weight you want. You have not mentioned what wood you have used. This makes a big diff.

What I have done in the past, is make a 68" bow at a weight of 45/50 lbs. Shoot it for a half year, then cut it down to 60", re tiller, then put 6 layers of sinew on it.

The bow ends up in the 65lb range, shoots considerably fast, and is super quiet.

[hoosierarcher]

FVR if he has a long draw he can't go shorter. I pull an honest 29 inches, 30 if I've been exercising regularly. I have to build my bows quite a bit longer than my friends and I can't shoot their bows. The reverse is not true.Mine are basically overbuilt to them and they find them to be smooth shooting.

[hoosierarcher]

As to backing with sinew cover the sinew with snakeskin or rawhide to help contain it and inprove the bow's appearance.

[FVR]

Best sealant that I've found for covering sinew is 7 coats of clear spraypaint. Then wax a few times. Completely sealed, do it over a snakeskin if ya like the look. I prefer the look of sinew.

As far as going shorter, don't know about you but I've built 48 and 50 inch bows that pull 28". It's the design of the bow, the amount of working limb, does it bend through the handle, etc. When you add sinew aka natures fiberglass, you can do wonders with the right wood.

Then we get into how much sinew is he going to need to apply to get the results he wants, then compare that to the weight that is going to be added to the limbs, will this weight and mass be benifitial?

For him to raise his bow 5lbs in draw weight, he may be better off cutting off two inches of limbtip, re tillering correctly and shooting it in.

Person. I would cut the bad boy down 4 inches on each limbtip, re-tiller, and add a few layers (4) of sinew, then re-tiller again. I've taken 45lb selfbows, done this and ended up with a 60lb bow that I can draw 28/29".

There are so many variables here; what kind of wood, what is the design, how much working limb, are the limb tips recurved.

Ahhhh.........there is an idea, cut the bow down 2 inches on each limb, recurve tips, then add 3 layers of sinew.