How to determine if a bow string is too stretchy or too stiff?

[Bowyer Wannabe]

Hi, I am using just regular hardware store nylon string on my bows. Problem is that it is kind of stretchy (or at least I think it is) and this affects the draw weight of my bows. I have never even touched Dacron in my life, so I don't know how stretchy Dacron is as compared to my nylon strings. I know that a little bit of stretch is good, but how much exactly?

Is there a rule or a formula for bow string stretch? How to measure what the stretch on your current bow string is and how to find out what the "right" amount of stretch should be?
Thanks!

[PlanB]

Nylon is a very stretchy fiber -- that's why we use nylon lines for anchors and dock lines in boating -- absorbs shocks.

Dacron (polyester) is used where we don't want stretch -- halyards, etc.

Bow strings seem also to be made of polyesters and Dacron. Either purpose made for strings, or some types of fishing lines with specialized polyesters.

[DC]

The "right" amount is none. Well almost none. Not even considering anything else a bow is much nicer to string with a low stretch string. I think nylon is about the worst for strech. When I started I used Spectra fishing line. It worked fine, I would still use it in a pinch.

[le0n]

dacron will stretch on initial bracing/use, but stops at a certain point. once it is stretched, you adjust by twisting (shortening) to re-establish your brace height. afterward, it doesn't stretch again, allowing the energy to be properly transferred to the arrow.

[OTDEAN]

Make yourself a low poundage bow of about 35lb - 40lb and try making your own strings out of hemp twine that is 0.5mm in thickness.  I have found from trial and error that with a 2 ply bow string made up of ply that has 5 strands each of 0.5mm hemp twine I get great bow string as long as I keep the string slightly wet.

I protect the loop on the main bow string using a turkish loop.     This stops the main loop of the main string wearing away.  I learned this from Primitive Tims video on U tube.

If you make higher poundage bows, just increase the number of strands to each ply or go for a three ply bow string.  Tim made a great video which inspired me to experiment.  Glad I did.  I now use plant fibre strings that have very low stretch and you can really tell the difference in cast.  Before I used B50 and the difference is amazing.  The B50 was like using a rubber band and seemed to rob the arrow of energy.    The hemp really seems to transmit the energy from the limbs to the arrow far more effectively.  Just my experience and opinion.

Dean

[Joec123able]

The least amount of stretch possible. A sketchy string absorbs some of the energy that should be imparted to the arrow.

[Bowyer Wannabe]

Make yourself a low poundage bow of about 35lb - 40lb and try making your own strings out of hemp twine that is 0.5mm in thickness.  I have found from trial and error that with a 2 ply bow string made up of ply that has 5 strands each of 0.5mm hemp twine I get great bow string as long as I keep the string slightly wet.

I protect the bowyers knot using a turkish loop.     This stops the main loop of the main string wearing away.  I learned this from Primitive Tims video on U tube.

If you make higher poundage bows, just increase the number of strands to each ply or go for a three ply bow string.  Tim made a great video which inspired me to experiment.  Glad I did.  I now use plant fibre strings that have very low stretch and you can really tell the difference in cast.  Before I used B50 and the difference is amazing.  The B50 was like using a rubber band and seemed to rob the arrow of energ.    The hemp really seems to transmit the energy from the limbs to the arrow far more effectively.  Just my experience and opinion.

Dean

Thanks a lot, that's really cool. I do have hemp twine. It is kind of thick, though, probably thicker than 0.5mm, but I think I will try to make a string out of it anyway.
By the way, I have read that hemp strings tend to be too heavy because you have to make them thicker in order to make them strong enough. Not sure if this is true or not. Guess you just debunked that myth, Dean.

[OTDEAN]

I can only say from my own experiences mate.  I have not tried with thicker hemp because you wont be able to use as many strands into each ply.  I seem to recall that the more strands used to make a ply in a plant fibre bowstring is what gives this type of string its strength.

I will say that your arrow nocks have to be larger to compensate for the size of the string.  You could try and teach yourself using the larger hemp that you have and when you feel comfortable with the process, buy yourself some thinner hemp twine.  IF you use 1mm thickness you will find your bow string is massive I reckon.

Dean

[Bowyer Wannabe]

I am afraid that I only have access to 1mm thick hemp twine. However, it consists of 3 thinner twines, which I guess, can be un-braided and could be used for the making of the bow string.

[le0n]

separate those strands and see how many pounds one strand can take before breaking.

[riverrat]

hemp strings arent too heavy unless your making them too thick.ive used them for years now. work just fine.Tony

[PatM]

Dacron IS polyester. Fishing line in made with polyethylene.

[PlanB]

Dacron is a trade name for one type of polyester. All polyesters are not Dacron. Fishing line is made from a lot of different materials. Monofilament for instance is nylon. There are braided polyester lines. Wasn't aware polyethylene was used, but not up on the latest there.

[PlanB]

Looked it up, and yes indeed polyethylene fishing lines are the thing these days. And that's the Dyneema you guys are talking about. Guess I'm behind the times on that. 

[PatM]

Yes, I was referring to the modern braids which make great endless strings   Dacron is a brand name but a lot of polyester is pretty similar when it is obtained in untwisted form.
 You can buy polyester lacing for aircraft at Aircraft Spruce or sailmaking polyester at Lee Valley  that works exceptionally well.
   For some people finding non-specific bowstring  material is a bit easier if they know the facts about what they are getting.