B50 streching AFTER break in?

[sticksnstones]

I made a Flemish twist 16 strand B50 string last week for one of my Hill bows. I pre-stretched it, strung the bow several times, and put about 100 shots on it so far. Every time I get ready to unstring the bow I check the brace and I find it's down to 6 1/4" so I put one twist into the string when I hang it up. I've probably done this 4 or 5 times.

Now the weird part; I strung it this morning and measured it before I shot it. 6 7/8"! Within a minute of just sitting it was down to 6 5/8". I hung it back up and waited an hour and it was down to just under 6 1/2" where I want it. It didn't seem to be moving so I shot it a dozen times and hung it up for another 2 hours. It hasn't moved any more.

Is this normal? I've never seen it before, but I've never studied a B50 string on a 80# longbow before either.
Thom

[Dave Lay]

i have found B50 to continue to stretch dang near forever...

[ironmike]

sounds like the string was made improperly, it is important that each strand is the exact same length and that the twist rate is right,also that the loops are back spliced right..other wise the shorter strands stretch taking all the work,and the longer ones just take a ride doing nothing..about three twists per inch in was the finished string should have, more after break in..keep at it, you'll get it..b50 is good stuff..

[LBR]

It's normal.  B-50 is very elastic--untring, it will contract.  Re-string, it stretches again.  In higher temps, it will stretch even more.  One of the main reasons I prefer HMPE materials.

[LBR]

FWIW, B-55 is better (less elastic), but it's still polyester and it will still stretch.

[Steelhead]

I keep my my bows strung most of the time and with my B-50 string they effentially settle in and stay put.These are proffessionally built strings by trad gang sponsers

A high strand count B-50 string may be best for your 80 # bow and reduce the amount of stretch.

I now use B-55 on the bows that I use polyester strings on.

[sticksnstones]

Thanks for your thoughts Chad, I always appreciate your insights when it comes to string making!

I wasn't aware of the contraction aspect of so seeing it this morning was pretty alarming. I'm guessing 14-16 strands on a 40-50 pound bow wouldn't be so noticeable.

Usually I just use B50 for selfbows, old recurves, and pike flies. Probably won't buy any more of it.
Thom

[**DONOTDELETE**]

Can you say rubber band bro...  They creep at anchor if you hold long enough...    

There are way too many good products out there to mess with B-50 bro...

[LBR]

Glad to help--I don't claim to know it all, but I've picked upon a few things here and there.

On my stretching jig you can watch the string contract--I've shown it to lots of folks, always enjoy the look on their face--lol.

[TSP]

Coincidentally, I just came in from shooting one of my Hills, equipped with B-50.  The brace had settled slightly from the last outing with it about a month ago, and it's an older string, but dang if I could tell any difference in accuracy between the B-50 and my other two Hills that have FF strings.  The differences I see with B-50 are that B-50 produces a bit more hand shock (but not by much); it stretches more (but not a big problem); it's quieter than FF; and it is a bit slower than FF (some of that is probably due to less string mass on FF).  I've swapped strings among the three bows (they are all 66" and all within a few pounds of each other) and these differences seem consistent.  This is after shooting these bows for several years now.  

I believe the only sizable advantage of FF over dacron is it's durability...the FF strings last a LONG time.  But then again, dacron string materials are soooo much less expensive (like 75-80% less).
 
Both work well for hunting and regular fun shooting.

[LBR]

There are tons of variables--whether they matter or not depends on a bunch more variable.  I've shot bows where 1/4" difference in brace height made a big difference in the way it feels.

Durability is a big one.  Lack of stretch and creep are big for me, as is reduced hand shock.  Haven't had a problem with bow noise.  The tiny performance difference doesn't matter to me one way or the other.

A spool of polyester ("dacron") string material is a lot cheaper...but break it down to a per-string cost, the difference is still minimal.

I'm to a point where I won't buy a bow to shoot if it's not made to accept HMPE materials.  I own a few, that have sentimental value, but I didn't buy any of them.

[nick straatmann]

I will usually throw a new b50 on hit it with a hair dryer (even though I have no hair) for a few minutes to let it settle before shooting in. Seems to help on break in time

[fujimo]

Ok, so heres a million dollar question-
and i know it has been beaten to death, but just asking you guys- what is the best string material- i only use endless loop strings.
glass( kenny - m) bows and wooden self bows.
by best i mean; best performance, at the best price- not trying to eek out every last fps. just want good consistant performance- that will enhance potential accuracy and not detract from it---i need all the help i can get!!  :rolleyes:

[TSP]

Honestly, it's hard to find any string material made today that won't deliver 'good consistent performance'.  There are lots of other places to look if you want to find performance problems/opportunities to improve...usually starting with the shooter, lol.

[Gordon Jabben]

Thom, it sounds normal to me for B-50 especially if you have a lot of twist in it.  As for the best string material, I like the feel of B-50 when I shoot probably because it is what I'm used to and I don't have any reason to change.  Some of the new materials are more durable and have a different feel that most people like.

[LBR]

what is the best string material-

From a technical standpoint, BCY-X.  In incorporates the highest grade Dyneema (SK-90) with a small amount of Vectran (17%) for the best durability and stability, plus it's quiet.

How the string is made will make as much or more difference than the material itself though.  A lousy string is a lousy string, even if made with the best material.

[Bldtrailer]

I found that B-55 has less strech(than B50) and seems  quiter, but I also find that my D97  strings seem to also strech  for a long time.

[**DONOTDELETE**]

Originally posted by Bldtrailer:
I found that B-55 has less strech(than B50) and seems  quiter, but I also find that my D97  strings seem to also strech  for a long time.

If you have D-97 strings stretching for a long time i'd say the string wasn't built well. Nothing streachy about that product at all.

[LBR]

B-55 is a better quality polyester ("dacron")--less stretch and creep than B-50 or B-500, but still considerably more than the HMPE materials.

The stretch/creep with Dynaflight '97 varies depending on a few things:  draw weight, strand count, temps, and how the string was built.  The things that will cause it to stretch/creep more are:  higher draw weight, lower strand count, higher temps (any 100% Dyneema string material will stretch more in higher temps), and obviously how the string was built.

BCY-X pretty well takes care of most of those problems.  Tiny strand, so you can make a fairly "skinny" string if you want, but still have a moderate strand count.  Higher grade Dyneema plus Vectran, so it's not affected much by high temps.

Dynaflight '97 was my "go to" material for years, but the X has taken it's place at the top of my list.

[Walt Francis]

Chad,
How does the BCY-X compare to  Brownell's Astro Flight.