I just made a bowstring from the 70# artificial sinew that 3 Rivers sells, I love the stuff but the string is too fat. I made a 12 stand string which is what I would normally make for a 43# bow.
I'm sure I'd be better off with a 10 stander. But do you think I could get away with an 8?

Thanks,
Zack

I wouldn't use artificial sinew for a bow string especially for a heavy bow. You can make bow string with artificial sinew but it stretcher quite a bit so you have to prestretch it by hanging a heavy object from it for a while.

You can make it thinner, sure, but that stuff is heavy and streatchy and generally doesn't make real good bowstings.  However, if it's what a guy has on hand.... I totally get it.

I have made a bow string from both artificial and real sinew.  Both stretched quite a bit but were durable.

Most artificial sinew is nylon and it stretches. That will rob your bow of performance, sometimes a lot of performance.
Not to ignore your actual question but you'd be a lot better off with a spool of B-50 or B-500.

Guy

I wouldn't use it at all, terrible abrasion resistance, stretchy,etc....in my opinion, not a good choice at all for bowstrings.

Yea if you want sinew then use the real stuff if you have to use something artificial it might as well be b-50.