String material?

[Hawkdancer]

Is there any real advantage to using "Fast Flight" or B55 over B-50, or "Dynaflight 97?  I currently use B50.  I am assuming that "creep" and "stretch, are the same term.  I have a very old fg  longbow, an Osage selfbow, a Bear Kodiak Magnum, and a pair of old "ShimBows",  haven't worn out a string, as I haven't been shooting that much.  Almost always use a stringer to brace.  Thanks for your opinions.
Hawkdancer

[PatM]

Yes. Very many real advantages.

[High-Desert]

Got extremely frustrated with B50, Switched to FF, and won't even consider Usin B50 again. FF is cheaper too for the amount of strings you can make from a roll.

[DC]

Creep is permanent, stretch is temporary I believe.

[NorthHeart]

Fast Flight is much faster than B50(i have material in both).  Fiberglass trad guys claim that without a hard material tip overlay the non stretch material can crack the tip of the limb.  On my primitive bows as well as every glass trad bow ive owned ive never once had this issue.  Knock on wood(no pun intended).  Have yall had any negative experience regarding this?

[PEARL DRUMS]

I use nothing but low stretch materials and have for years. Hard to beat in every aspect from durability to cost.

[gfugal]

B-50 is made of polyester no? I once read that polyester has a stiffness (MOE) of around 8 GPa wheras Dynema (which fast flight is made of) has a MOE above a 100 GPa. Now B-50 may be a higher grade polyester than the polyester they may have tested that gave that number i read about, but it illustrates the stark contrast between the two. Even a flax/linen string which is all natural should be stiffer than polyester.

[pnwarcher]

I read somewhere (one of the bowyer' bibles?) the switching from B50 (polyester) to a fast flight (UHMW polyethylene) material is roughly equivalent to adding 5 pounds of draw weight, in terms of effect on cast. That is, for example, a 45 pound bow with fast flight will shoot an arrow with equal cast as a 50 pound bow using B50. Based on my anecdotal experience with the two, I believe it.
I think the real advantage is that the high stiffness and strength of fast flight material allows you to make a string of fewer strands, which is therefore lighter weight than a B50 string and therefore less of the bow's energy is lost to accelerating the string, leaving more to go into the arrow.

[simson]

Maybe this is helpful:
http://primitive-bows.com/about-strings/

[gfugal]

I read somewhere (one of the bowyer' bibles?) the switching from B50 (polyester) to a fast flight (UHMW polyethylene) material is roughly equivalent to adding 5 pounds of draw weight, in terms of effect on cast. That is, for example, a 45 pound bow with fast flight will shoot an arrow with equal cast as a 50 pound bow using B50. Based on my anecdotal experience with the two, I believe it.
I think the real advantage is that the high stiffness and strength of fast flight material allows you to make a string of fewer strands, which is therefore lighter weight than a B50 string and therefore less of the bow's energy is lost to accelerating the string, leaving more to go into the arrow.

Stiffness and tensile strength aren't the same thing. Theoretically you could have a stiff string that broke fairly easy, or a stretchy string that could handle a lot of weight. The higher the tensile strength the less material you need thus reducing weight. The higher the stiffness, the less the string stretches when shooting. Linen string is an example of a material that is stiff but has a lower tensile strength comparatively, especially when dry
 Dyneema in fast flight, on the other hand, happens to be both stiff and very strong. Most people with fast flight overbuild their string significantly only for the sake of having a string thick enough to nock well. B-50 has good tensile strength and is probably why it's used so frequently. They tend to be overbuilt as well, when a thinner and lighter string would technically work if it wasn't for nocking purposes. I think the improvement from switching to fast flight is not in weight but stretch.

I made strings from polyester thread, which is technically the same material as B-50, since davron is a brand name for polyester (PET). However, when i videod me firing my wimpy 30 lb bow i saw the string stretched so much that the limbs practically returned to their embraced profile. And despite a 6" brace it just barely missed smacking my wrist. You can try it yourself if you have a new smart phone, to see how much it stretches. I'm not entirely sure how it works but essentially it boils down energy that could have gone to arrow speed is rather lostt in the follow through of the limbs and string stretching

[Pat B]

I've been building wood bows for 30+ years now and have always been satisfied with B-50, B-55, mostly B-50. I've had people try to convince me otherwise but as far as I'm concerned B-50 is good enough for me and my bows. 

[gfugal]

I've been building wood bows for 30+ years now and have always been satisfied with B-50, B-55, mostly B-50. I've had people try to convince me otherwise but as far as I'm concerned B-50 is good enough for me and my bows.

Never said it wasn't good enough. It makes fine string material, as will sinew which also stretches quite a bit. But the question was if there was a difference.

[Pat B]

Yes, there is quite a difference.

[Springbuck]

Fast Flight is much faster than B50(i have material in both).  Fiberglass trad guys claim that without a hard material tip overlay the non stretch material can crack the tip of the limb.  Have yall had any negative experience regarding this?

I ripped the entire tip off a 1992 or so 65lb Martin Hunter (made pre-FF era) when I had an arrow nock split, causing a dryfire.  The string split the top limb lengthwise into three sections, from the deepest part of the string nocks down about 3" down into the fiberglass,.  Basically it ripped about a 1/2" splint out of the middle of the limb, leaving splints on each side.

Most bowyer upgraded their limb tips short after with linen micarta, carbon, and phenolic overlays to shoot FF, but I would be careful using it on older "classic" bows from the 60's, 70's, and 80's.

However, on wooden bows, I have never had a problem.  I think most designs just don't store the energy something like a high draw weight FG deflex/ huge recurve does, so I use bot low stretch veg fibers and FF on my selfbows, too. If I make overlays, I use multiple thin layers and very strong glue, so the grain of each sits at a slight bias (sort of like plywood, I guess?)  I also learned not to make overlays from wood that is super soft or splits easily.  BLOCUST is very strong, but will split clean and easy, as will black walnut..  So will some exotics like purple heart.  Mulberry heartwood or pear won't so much.

[Weylin]

Big difference. I only use fastflight or D97. I would like to learn to work with linen at some point but have no interest in using b50.