Would any of you guys advise against making a bow string from cordage made from plant fibers? I'd like to stick to natural materials and I've really only seen guys use sinew. Just checking my options.
I have used jute successfully in a bowstring for a #70 bow. However, it was not durable(it broke at the nock, every time I strung the bow it rubbed on concrete)... but I think a properly made fiber bowstring is extremely durable.
Sinew is popular because it has 2 properties- high stretch and high strength. When you shoot a bow, the most stress occurs not at full draw, but when the limbs slam home and the string is suddenly straightened. That is when bowstrings most often break.
An elastic material like sinew absorbs much of the shock, stretching slightly, reducing stress on the string- same amount of force, spread out= less deceleration and less stress on the string
An inelastic plant fiber doesn't want to stretch at all, massively increasing the stress on the string- same amount of force, concentrated= more deceleration and more stress on the string.
Its like asking which is more powerful- a pound of gasoline or a pound of TNT- The gasoline releases vastly more energy, but the TNT delivers what little energy it has with enough speed to shatter rock(the burn is nearly instantaneous, instead of being spread out like gasoline)
Dacron B50(a popular string material) stretches a small amount under stress.
Plant fiber strings, IMO are best in wet conditions cause sinew stretches when moist.
Seal your string to prevent that.
According to multiple books I have read, self bows with dogbane, nettle, etc. strings were made and used up and down the west coast, when it would be hard to keep a backed bow dry.
I suggest linen or flax fiber, unbleached, because its very strong, durable, and available(for adults). Or unbleached linen string or thread. Linen strings were used on English warbows because linen was strong enough for the bows' #100+ draws.
It is also quite durable. Make sure you wax any plant fiber string well.
Don't expect a nettle, dogbane, or other fiber string to last as long as a well-made sinew or B50 string.