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polyester rope as bow sring? Answered

Picture of

i will soon post an instructable on how to make a reverse compound crossbow. but i've been stuck into something which is quite basic,

the string that needs to be used, 

the crossbow will have a draw weight of about 150-175lbs.

i have came across a rope  which has a diameter of 4mm, and claims to withstand a tension of 1500N(150KG)

I just want to know if it would be ok to use the rope, 

i  know that it is very important to use a string specially made for bows and crossbows but we all like it dangerous(especially if you're broke)

thanks in advance

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user
Downunder35mBest Answer (author)2015-08-07

You want two qualitiy in a line for this job:
a) Breaking strenght at least 50% above the max needed for the bow.
b) No elasticity in the line at all.

Something with a wooven pattern like the one in your pic is useless, unless the outside is only for protection of straight fibres that take the actual load, on the inside.
As mentionen Paracord has these straight strands.
For my projects back in the day I only used Dyneema line.
It has superior qualities and lasts long.
But best of all: It is about the thinnest you can get when it comes to breaking strenght.
A 50LBS fishing line made from Dyneema is less than 0.5mm thick....

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user
cerberustugowar (author)2015-08-07

if you can get a few 4 foot chunks, you may be able to test it's true breaking strength weight weights or body mass. Better to find out before you draw it and end up punching yourself in the face

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rickharris (author)2015-08-07

You could try it - Many similar bows use para cord as a string although they do fray quite quickly.

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