The bow in TBB Volume One page 110 cable questions

[Jax666]

I have not been able to find unbleached silk string. I have some 48 lbs test hemp string, would it work? I have heard hemp has less stretch than silk or sinew? I have heard of artificial sinew. Does it have the same properties as sinew? I assume it is a synthetic? nylon? so would not be real primitive.

Thanks,
Jerry

[joachimM]

For the same diameter, hemp is about six to twelve times stiffer than silk, and it stretches much less, about 1.5%.
Silk from the mulberry moth has no clear yield point, and can easily stretch 5%.
So there is a huge difference between both fibers.

Artificial sinew is just a kind of nylon. But in terms of stretch and strain, it resembles sinew to some extent, except for the shrinkage part when drying. No, that wouldn't be primitive, but neither is epoxy, or steel sleeves in takedowns, or all kinds of varnish, or a bandsaw, ...

Joachim

[Hrothgar]

I don't recall an 'official' categorizing for artificial sinew, butI a lot of people on this site use it on bows and especially arrows. Think colored dental floss. I made a cable backed bow several years ago. It worked well, and added some weight, however I'm sure other materials such as real sinew would work better.

[Jax666]

Hrothgar, did you use the artificial sinew for the cordage?
Jerry

[Pat B]

Rich(halfeye) has made cable bows. I have one of his and it has what I think is an artificial sinew cable.  Silk is more elastic I think; it stretches but also recovers.
  Rich just did a build along with a Penobscot bow and experimentation with different materials for the back bow strings.
Maybe Rich will chime in with some help for you.

[Jax666]

Thanks Pat!

[Hrothgar]

I used the artificial sinew for the cordage, but like Pat said silk is better.

[Jax666]

Where do you find the unbleached silk?

[willie]

I have seen artificial sinew made from nylon, and made from polyester.
It should say on the package

polyester doesn't stretch much, but it does stretch better than flax or wood , think B-50
nylon is real stretchy ..... mason twine

[joachimM]

polyproplyene cordage (which is also used as twine to keep pressed hay bales together) is pretty stretchy stuff. Have wanted to try that for some time as a backing.
Dacron and Vectran (polyethylene terephtalate), is also very good  stuff because it has virtually no creep, much less than HMPE ropes such as Dyneema and Spectra.

[Jax666]

JoachimM, One thing I have plenty of is hay twine, but it is in short pieces so would need spliced. I have horses! Maybe I could pick up a part roll from the man who bales my hay. I my try a low power bow string out of the hemp

[TimPotter]

Here is a great link on doing it 100% authentic. Which I still want to try one day.

http://elfshotgallery.blogspot.com/2010_01_01_archive.html

And here is one I did using jute rope some years back. I recently took off the rope because I want to try it with rawhide at least. I have 1 large deer skin and several 1lb freezer bags of white tail leg sinew, but I would rather use my sinew on several NA style short bows in the works.

http://paleoplanet69529.yuku.com/topic/14170

The cool thing about the cable is that it allows the use of wood that I wouldn't think could stay together, pretty nifty if you have no other options than driftwood or old barrels or pallets.