Some of you may find this interesting and useful... Others, their heads may explode...
Got this off facebook... It's by Sid of Border bows...
Several years ago we started advising folks not to use certain strings and to consider the strength of the string.... the strength of a string will dictate how much of its elastcity you get access too.
For example. If 1 strand stretches 10% of its length at full load. And that full load is 100lbs. And another stretches 20% at full load which is 200lbs... both string should stretch the same amount at 100lbs.
But if you took half a strand of the second string. Ie 100lbs. You would get full access to its 20% elasticity.
Overbuilding a string will make it soooo strong that you loose access to the strings elastcity.
A result of this hot topic was a customer sent us this table, with thier working out. And we smiled.
Someone fully understood our point of view.
Just look at Rhino. 122lb strength. With 2.7%elongation at 80% load.
Look at lovely 8125. 87lbs strength. 3.4% elasticty at 80% load.
Which ones going to be kind to your limbs?
We dont recomend 452x. 85lb strength. 2.4% elastisty.
The three example materials at 3 different strand counts each in the lower table. At a theortical equal 1000lb requirment delivers some horrible elongation results.
Dacron B50 doesnt break bows...48lb strength. With 10% elongation... but you do need more strands to make up for its softer nature....
Now.... it gets messy when you consider. That the actual elongation is a % of its length under a certain load. 72" bows will have more elasticty available to them, than a 58"
(Please note the coment about how the materials spun in the table)
And limb failures are a result of impact energy vs string strength.
Impact energy is a result of poundage, draw length, limb design/construction, and arrow mass. String strength is also a function of how the string is twisted by the twiddler.
8 twists per inch will deliver more elastcity than 1twists.
But the diamiter of the bundle will also effect the elasticty gained per twist.
Hope this helps show why we wish you consider your string choice.
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