A Question about Sinew

[GraemeK]

Has anyone tried to use epoxy or any other non animal glue to sinew a bow --- if so was it successfully.
I would like to build a bamboo sinew horse bow but would prefer to avoid the moisture problems that animal glue would give me.

Graeme

[Pappy]

I haven't personally use it but Dirty Dan a friend that is on this site sometimes said he used TB2
on some and it worked well.I know it would help with the moisture problem.
   Pappy

[GraemeK]

Hi Pappy
Yes I thought the best chance was TB2 or something like it as the chemical composition (polyaliphatic) is very similar to protein colloid glue so I am glad to hear that someone has tried it with success. I figured the epoxies and the like would be too stiff and low stretch but it never hurts to ask as there is always a chance someone has tried it.
Graeme

[Hillbilly]

Art Butner swears by titebond for putting on sinew. Never tried it myself, but it apparantly works. I'm unclear about whether it has the same capacity to pull the bow into reflex as the combo of hide glue and sinew, but it would be a lot more water resistant.

[GraemeK]

Hi Hillbilly
Yep the one thing that only animal glue will do is shrink and induce reflex. Which I guess is a bit of a disadvantage but pulling the bow into reflex prior to glueing should work OK in general and for my application the bow will be built on a form with severe reflex to begin with.   GKL

[Pat B]

Art uses TBIII on bows with good results. I used it on the last course of sinew on Elkie the bow I built for my elk hunt last fall. I also did the repair on  Elkie with TBIII, where the sinew lifted from the wood. On my next sinew bow I will try a shorty, probably ERC and TBIII for glue. I believe you will have to add reflex while adding the sinew for it to hold the reflex. One small problem Art mentioned to me was that his bows would increase in weight during cold weather...up to about 10#.     Pat

ps. TBIII is waterproof after it cures. The other TB glues are only moisture resistant at best.   

[GraemeK]

Hi Pat
Sounds like the TB3 is the go. It will be interesting to see if I can make a short highly reflexed Asiatic style bow using just bamboo and sinew ---- GKL

[Pappy]

The last one I sinewed back I used hide glue for the sinew and put a snake skins on it with
TB3 and then sealed it and that seem to be keeping the moisture out.
   Pappy

[Pat B]

GKL, Try a small sinew/boo bow first and see how it will work. I would think that the boo and sinew would be a good combo.
Pappy, I too used the TBIII to put down the skin on Elkie and sealed over the top with it also before adding the regular finish.   Pat

[tom sawyer]

Question.  If sinew is basically the same material as hide glue, then what real advantage is there to using Titebond over simply using hide glue and then sealing it with a finish and/or snakeskins or silk?  I seem to recall that Paul Schafer was supposed to have always used sinew-backed bows in Alaska, in some of the moistest environments you can get.  That tells me that sinew and hide glue can be sealed properly.

Every time I hear of sinew being used with Titebond, I cringe a little.  Its not the traditional aspect I object to, rememebr I glued horn on a bow belly with resorcinol.   I just feel like a major advantage of sinew is when it shrinks and tightens up on the back.  It is already heavier than wood so not allowing it to pull into tension is underutilizing the material and negating some of its magic.

[Pat B]

Lennie, Here in the S E US where the humidity is quite high in the summer, as it probably where you live, the draw weight of these sinew backed bows changes from season to season. My Medicine Bow goes from 45# here  to 75# in Colorado as did Elkie. When done, both were about 55#. While using TBIII for the sinew that change can be less dramatic...it any.   Pat

[tom sawyer]

I read somewhere else that the sinew still pulls in some reflex with TB, is that your experience Pat?

I do know its tough to seal sinew properly, I've never liked putting an oil finish on it because it seems to soak in more than I'd like.

[Pat B]

Lennie, I have used it enough to say. I have heard that their drying times are differant. I guess that could cause problems. Wet sinew sealed in a waterproof package could get a bit ripe, I'd bet.     Pat

[GregB]

Putting the variation in how a bow is affected with hideglue/sinew from the varying humidity levels for different parts of the country aside, do you think the sinew would retain its ability to act as a primitive fiberglas for lack of a better comparison when adherred with TB3 versus hideglue? Or would it instead provide a reduced role of just protecting the back, as would be more the case for rawhide?

[Pat B]

Greg, I shot Art B's TBIII/sinew bow and it feels like there is more performance than with just a backed bow. Thats the only one I've shot. Knowing Art,  I don't think he would praise them if it were only for protection.   Pat