string building length question

[michiganman]

the guy i know in ohio built me two test strings.the problem i made was i sent him a new excalibur string that had not stretched into the brace heigth lines.its a inch above the lines.so the test strings came in at 35 5/16" same length.but being 8125 material,and 452 x,they probably wont stretch at all.

should they have been a total of 36" in length,thanks as always for your help.

do i need to maintain the brace heigth in the middle of the two lines,seems to shoot best there

[Stash]

452X doesn't stretch. A poorly made 452X string may seem like it's stretching, but it's the individual strands settling in and compressing against each other that give the illusion of the string stretching. The material itself has no significant stretch to it.

8125 has a tiny bit of stretchg in it, but for a string the thickness of a crossbow string it'll take forever for the string to stretch as much as you need.

450 Plus and 452X are blends of Dyneema and Vectran. Vectran has no creep at the tension created by normal bows, therefore both 450 Plus and 452X are normally 100% stable.

(BCY website)

The difference between "stretch" and "creep" isn't in my opinion worth discussing in the context of crossbow strings.

[GaryL]

Cant say much on this one, however should be able to twist up your string or un-twist to meet your brace height. On the other hand however the way I read your post is the string is WAY too short.. If thats the case I would get him to make a NEW STRING foy ya!!

GaryL ....

[michiganman]

the strings are 5/8" above the top line.looks like they should have been 36" long.they are probably a 1/4" short.

the 452x i had on my bow moved just a little over a 1000 shots.they must make the excel strings a little short and they stretch into place after a few days,

[Boo]

the strings are 5/8" above the top line.looks like they should have been 36" long.they are probably a 1/4" short.

the 452x i had on my bow moved just a little over a 1000 shots.they must make the excel strings a little short and they stretch into place after a few days,

Jim, the longer the string the more total creep. With very few twists in the endless loop string of yours you might have to settle for something less than perfect but there's no harm is shooting your bow at or just above the highest brace height mark. You are making the right decision to wait!
I find that I like the way by bows shoot best with a brace height somewhere between the highest mark and half way with the preferred spot a string width or two below the highest mark.

[michiganman]

thanks Boo
i dont want to test them new ones out till i can afford a sts,and have shot the xbow more.i dont want to blow a limb up ,with my first dry fire,JIM

[Stash]

The Excel string is dacron, which does have considerable elasticity and creep.

"Stretch" is the term used for a material that stretches under tension but then retracts when the tension is removed, like a rubber band.

"Creep" is the term used for progressive elongation that does not retract.

Dacron has both stretch and creep - it will eventually stretch out quite a bit and you have to continually add twists for the life of the string. Quite a few the first time you put it on the bow and progressively less as time goes by, but if you take it off and let it sit for a few days, you will find it has contracted a bit the next time you put it on the bow and you have to take a few twists out of it at first.

Fastflite has very little stretch compared to dacron, but it does have some, and it also has some creep.

452 has neither - once the string settles in after the initial compression of the strands, it stays where it is for the life of the string.

[Boo]

The Excel string is dacron, which does have considerable elasticity and creep.

"Stretch" is the term used for a material that stretches under tension but then retracts when the tension is removed, like a rubber band.

"Creep" is the term used for progressive elongation that does not retract.

Dacron has both stretch and creep - it will eventually stretch out quite a bit and you have to continually add twists for the life of the string. Quite a few the first time you put it on the bow and progressively less as time goes by, but if you take it off and let it sit for a few days, you will find it has contracted a bit the next time you put it on the bow and you have to take a few twists out of it at first.

Fastflite has very little stretch compared to dacron, but it does have some, and it also has some creep.

452 has neither - once the string settles in after the initial compression of the strands, it stays where it is for the life of the string.

Well done Stan!