Out of Curiosity......("FF" strings)
 

Has anyone ever seen, or heard of, or even had it explained to you, how a "FF" string can cause a bow to delaminate?

I asked for some facts on a different board, but evidently none can be offered.

I honestly don't know. The majority of bows I've seen fail, and the ones that failed with personal friends, either did it with a dacron string or on the first pull.

When a bow has a FF type string on it and it fails, the "knee jerk" reaction is to blame the string. I dare say that at least as many, and probably a lot more, bows have failed with non FF strings on them--so what gets the blame for those?

On the other hand, lots of bows have been shot for years and years with FF strings on them. Some folks are using FF strings on old bows (I don't suggest doing this) with no apparant ill effects. What makes one go and the other blow?

Another thing--one way to "tame" a bow with a lot of hand shock is with a FF type string. How can less shock be harder on the bow? Seems to me the opposite would be true, but I'm no bowyer so maybe I'm missing something here.

Hoping I can get some information on this here, or at least not get attacked over it. Took about 10 seconds on the other board before I got accused of saying things I didn't. Oh well....

Too fast for the tip overlays. When the tips fail, the lams pull. I make all my bows with tip overlays that will support ff stings, but i never use ff materials.. The little extra speed is negated by my heavy shafts. I have used dacron for years and do not plan on changing any time soon.

Never heard that before--that's an interesting theory.

I don't think speed has anything to do with it though. We're talking about an average of 5 fps or less difference on average, maybe 15 fps on the extreme side. You'll get more than that by switching from a guy with a 25" draw length to a guy with a 32" draw length--a lot more. Bows don't blow up just because someone has a longer draw.

On top of that, the speed gain is primarily because the HMPE string is more efficient--the difference in speed with the limb tips is very slight. We're talking grains of difference in string weight.

HMPE (FF type) materials don't turn a VW into a dragster. My theory on hand shock is this:

Hand shock is energy from the limbs not transferred to the arrow. It travels down the limbs to the riser and to your hand. Less efficient strings impart more hand shock, as do lighter arrows. HMPE materials are more efficient than dacron, so they impart less shock. Won't mean a lot to most recurve shooters (although I have shot a couple of recurves that were as bad as any longbow I've ever shot), but it will to a lot of longbow shooters--some designs, coupled with featherweight risers, can tear up an arthritic elbow.

Usually the slowest bow has the most shock: i.e. a lot of Jerry Hill longbows, the Martin Stick and Twig, straight limbed Hill and Hill style bows, etc. Tiny tips on some, but lots of shock. Usually it can be calmed down with a HMPE string.

That's my experience to date. The other thread had calmed down quite a bit, but seems to have dissapeared. Oh well....

That thread is back, but my last post is gone and it's locked. So much for honest debate and sharing ideas....

Counter productive to fuss over what admin at other sites do.

I don't think bows delaminate because of the type of string material, if I understand your meaning. When I think of delam, I think of the glass separating from the inner (wood) layers, more the inner wood layers tearing apart themselves. The former usually because of glue or fit failure, the latter frequently because of too much strain (or stress, I get them mixed up), usually in shear forces (where the lams move or attempt to move parallel to one another).

A bow don't know what kinda material the string is made of, strings don't break bows. Linen is both less mass and less stretch than Dacron, less than the new FF+ material I think. It's been used for millenia, and much preferred for these reasons. But a bow knows if the string has less stretch than it can handle, or (in combination w/ the arrow) less mass than it can handle.

Chad you can spend a decade, as you have and more, investigating this question with run of the mill folks on the internet, and you'll learn a whole lot more about the nature of men than the nature of bows and string material. Sorry to say this, but the "simple stick and string" is a misconception. Fact is, at least in terms of the down and dirty math, bow-n-arrow is a damned complex thing to model. Consequently, not much info is available mass market. The fllight shooter boys, over at paleo mostly, have got some computer models (spreadsheets) that do a fair job. String mass and elasticity can be "plugged in" to get an idea of how it influences the rest of the system, in terms of strain, performance, etc. But I'll warn you (having read older stuff from Kooi via Tapley) the math side will break your brain.

Other than for entertainment provided by interacting with others, little can be gained/learned from laymen. Sorry to sound such as arse. I'm not really. Hell I AM a layman, in these terms. But I am speaking from direct, personal experience, having done my decade too.

You make a lot of sense David, and I appreciate your input.

I know I was grasping at straws, but I really would like to know if anyone has done any kind of testing, and what the results were.

I couldn't remember if it was silk or linen--thanks for the refresher. I believe it has as little, maybe less, stretch as any of the FF type materials, but nobody blames it for blowing up bows.

I guess I just ask for too much. I thought that surely, as much as people proclaim without a doubt the evils of "Fast Flight" on traditional bows (especially older ones), surely someone had actually bothered to verify something.....ANYTHING.....pertaining to their steadfast declarations. After reading some of the claims made by a few so-called "icons", I should have known better.

I realize people have had old bows "blow up" while using "Fast Flight" strings. I dare say many more have "blown up" with linen, silk, dacron, etc. The only thing I can honestly garner from that is that bows sometimes break.

I'm not going to look for a flight shooting site....math makes my brain itch and my bowels irritable.....:bash:

I had a FF string on an old "zipper". The overlays were wood and fiberglass. I was getting cracking around the top. Bill Dunn, said FF did it. It confused me. I told him I shot well over 3-4K shots with FF on that bow. He said I was lucky. I ended up grinding off the wood/glass, and putting phenolic on.

I myself don't see how padded ff can cut thru a lam.

ff string damage is tip damage. Tip damage leads to limb damage. I know when I build a bow for a person using ff strings, there are only a few tip materials I can use. Wood tips will not support a fast flight string. Seen lots of people screw up bows with ff strings on wood overlays. I have fixed many, personally.

Which is what makes this question so perplexing, contradicting testimonials from credible sources.

I've put new new overlays and string grooves on perhaps a dozen glass bows. Some from scratch projects, some rehab jobs. Never used phelonic, only glass and wood, usually wood as the last or top layer.

I have an old Bobby Lofton bow I shortened, piked, and re-tillered. I used elm on top of the existing (looked like .040) clear glass. No worries. Bow is mid 50s at 30", shoots like a house afire compared to typical production mild r/d bows, especially Bobby's run of the mill bows.

As importantly, in my view, I've made dozens of self bows, up to 70#, of woods as soft as yew (althought that bow only 50#) on up as hard as ipe and osage. Rarely use an overlay, even on boo backed, never had a problem.

It can drive a person to madness, because I refuse to take the easy way out by assuming the contradicting antecdotes not credible. But I certainly can't account for the vast differences in experiences.

I tend to fall back upon the theory we aren't really comparing equally in some way, that my experience is subtlly differnent than others. For example I rarely shoot less than 8 grains per pound, rarely shoot over 70#. But I do draw a full 30", and on bows optimized for cast, r/d longbows as short as 60" and use reasonably low mass, low stretch strings, 12 to 14 strand FF, d97, 6 to 8 strand 450+, etc., even linen. And I'm very meticulous about how I design and shape string grooves.

The thing about the flight shooter boys is, they don't mess around about working within the limits of the bow. They run right up to edge of the envelope, and frequently beyond. If they don't know what breaks bows, unlikely yer average 10 gpp hunter, setup with a 400 grain string for "quietness" is gonna stumble on any epithany they haven't already exercised thoroughly. Very uncommon to have an experienced flight shooter scapegoat a string. Rather they tend to accept they've crossed the line in terms of (bow) materials capacity and/or bow design, because their purpose is to use as little string and arrow mass as they can, designing bows accordingly and literally breaking bows occasionally, frequently breaking strings, to find that fine line.

No question a bow string can tear out string grooves. But I don't think you can accurately, fairly, lay all that at the feet of the string material. Rather the size and shape of the string grooves makes all the difference. From an engineering point of view, a chain is only as strong as it's weakest link. Similarly, if you concentrate forces, for example with improperly shaped grooves, stress will exploit that condition... to failure in extreme cases.

I understand what everyone is confused about.

I know when Bill from zippers saw I had a FF string on, he was really alarmed and told me to immediately quit using that string. He asked how many times I have shot that bow with FF on. I expalined 3-5K shots.


I think bill knows what he is doing, but the proof was in the pudding. I shot lots of shots with FF and the glass just began to crack. It could have cracked with dacron.

Once again, David is spot on. I don't doubt Bernie's skills or knowledge...but I know Eric Krewson normally uses wood overlays on his selfbows, and HMPE (usually Dynaflight '97, I think) strings.

I know my own favorite bow, that I pull [email protected]" on, that I've never shot more than 10 gpp on and generally less, that I draw to 30", that I get well over 180 fps with, that I've shot tens if not hundreds of thousands of times over the past 12-15 years....has wood overlays on the limb tips, and it's doing just fine even though it's NEVER had a dacron string on it.

Back to the discussion on speed.....I accidently ran across an interesting tidbit about picking up 6-12 fps just with a proper anchor and release (it's on the safari tuff site under "tips and trophies). That's as much or more than you'll typically pick up by changing strings.

This has been very interesting and enlightening, even if there hasn't been any real testing done. Thank you all for your input, and the civil way you presented it.

When it come to tip overlays, I go by the books. None of my bows, that I have built have ever suffered from limb damage. The bows I have repaired, due to string damage, have all followed along the lines of what I have read and studied. Personally, I have never pushed it. It is much easier to make a bone, phenolic,etc tip, than to risk other materials for the simple purpose of testing the limits. So I assume that is why I have never had any tip failure. I have yet to have a bow returned or brought back due to damage, and knock on wood, i wont. But I do insist that if a person is going to use a ff string, that I will use materials suggested for said string. Actually, most every bow i have ever sold has had tips made for any string. Like I said, it is much easier to just make a tip that can handle it. No need in pushing it.

After reading my reply's, I noticed I did not get across my point very well. To sum up what I was trying to say, and more so forgot to mention, is that ff strings do not stretch. The inertia created by the limb is stopped by the tips more violently, which lead to tip failure in softer material. I guess thats more along the lines I was trying to get at. This concept is one of the reasons, regardless of string, for tip overlays.

Think of it this way. Take a stick and strike a tree with it, the tree will not give and snap the stick. Hit a bail of hay with a stick and the hay will absorbed the strike and not break the stick. Dacron is hay and ff is the tree. After thinking about it, I get what you were saying about hand shock. I was not quite thinking right when I read your post. Sorry.

That makes sense (tree and stick). FF materials do have some stretch, just not nearly as much as dacron. The amount of stretch in dacron (or really any material) will vary with draw weight, draw length, strand count, etc.

I agree on not pushing the limits--that's why the latest "fad" of tiny strings makes me very nervous. There's quite a few advocating 4-6-8 strand strings. To me, that's nuts. Same fad went around some 12-15 years ago, but then it didn't get as low in strands as now. Thankfully, that one passed and I expect this one will also.

I'm not going to be the one that does any limit testing--I'm in the "better safe than sorry" crowd. I will constantly be looking for more information on strings though. If someone can show that HMPE strings will cause damage to certain bows, and why, then maybe we can figure out how to modify the string to avoid that and get the best of both.

There's some things about strings which may be counter-intuitive.

Handshock. An elastic string promotes vibration after the shot, because the string stores energy (like a rubber band) that has to go somewhere once the arrow has left the bow. Back to those flight shooter boys, the math indicates string mass is important, for maximizing cast, but also elasticity. When elasticity is set to zero (for modeling purposes), arrow goes faster. If the arrow goes faster, less energy is left in the bow, less handshock.

Low strand count strings. They have MORE elasticity, but less mass. If you don't offset the less mass by adding arrow mass, it's in effect the same as using (too) light arrows from the bow's pov. Also, when a strands breaking strenght is 150#, compared to inside of 50# for Dacron for example, you can, obviously, use 1/3rd less strands and still have the SAME breaking strenght. Elasticity is directly related to breaking strenght, one goes up so does the other. You do have to be careful about diameter, around the string loops, as a tiny string will obviously focus the strain on a smaller area. But if a 12 strand Dacron (600#) is "enough" string, so is 4 strands of 450+, for example.

The Walk the Talk boys found the more efficient (as differentiated from simply "faster") bows also had in common the least handshock, the least noise. Kinda counter intuitive, until you think about it. Energy leaving the bow by way of the arrow beats energy being absorded by the bow, for longevity, performance, quietness, everything. A bow can be faster because it stores more energy (a recurve), or because it delivers more of it's stored energy (an optimized r/d longbow). Of the two, the recurve is frequently the louder... because while it stores more energy and even though it puts more energy into the arrow it also wastes more energy slinging around that extra limb mass, which has to be consumed by way of noise and handshock. That recurves typically have such massive risers, in comparison to the more efficient r/d longbow shape, the handshock difference is frequently masked, not always obvious in the comparison.

Here's some of what bothers me with the tiny strings. On paper, it makes sense that a strand that is 3 times stronger would let you get away with using 1/3 the number of strands...but paper doesn't take other things into account.

Load testing. I hope I get my terms correct here....the breaking strengths are tested under static weight (stationary), not shock load--I think that makes a big difference.

Flexing. Every string material I know of that has been removed from the market (removed, not upgraded) was due to failure at a flex point--usually the nock-set. Some materials act like a wire--when they get flexed at the same point over and over, it breaks down the fibers and consequently the string breaks. I don't know how the load strength correllates here, but I do know the strongest material on the market today is the one I've heard about breaking the most--by far. It's also the one that has been used the most in tiny strings to date--450+.

The other thing that bothers me is durability. I can break an anvil with a feather, and I've had folks with similar luck contact me needing a string "right now", because of a mishap. Usually a case where broadhead meets string (like putting an arrow back in a bow quiver at dark), but there's also fences, sharp rocks, etc. One or two cut/broken strands might end a hunt, or might not. Three or four might require a new string, or might get you slapped upside the noggin by your bow limb. Either one depends on how many strands you have to begin with.

That's how I look at it, and what makes me wonder how dacron can be "easier" on a bow when it resonates all that vibration down the limbs at every shot. Another reason I don't care for tiny strings, is they can act the same way. All materials have some amount of stretch/creep. The lower the strand count, the more you increase the stretch/elasticity. Getting away from that is one of the main reasons I prefer HMPE materials to begin with. That, along with increased durability are pretty much the ONLY reasons--I'd use them if they were a little slower than dacron. Going with a tiny strand count takes away the two main reasons for using HMPE materials to begin with. That's why it puzzles me so much when I hear people brag on them....I just don't get it.

To be honest I don't know the relationship between breaking strenght (static) versus under shock load, but I'd imagine directly related. I found a fair bit of reading a while back on the topic of comparing materials in the context of rope, marine applications. Seems like I read Dacron stretches 5% compared to the HMPE stuff closer to 1%-2% as a function of breaking strenght (eg. size). They are all about stretch, shock load too, I'd be surprised if that testing didn't get done as well.

You make an excellent point about work fatique. Linen suffers from this, as you describe typically at the nock point. And I read with interest your thoughts about Vectran (I think, aka 450+) being particularly brittle.

I don't shoot enough to be overly concerned with plain durability. I've had two strings on that bow I bought from you (what 6 - 8 years ago). But risk of failure from calamity, intimacy with broadheads is certainly a legit argument.

I don't favor skinny strings, unless it's for a tiny little bow like wife or dotter. But I don't begrudge them either. I think folks generally delight in doing, proving from their pov, they can do what they've been told they can't, hence the brag, although it might be more tactfully label "enthusiastic sharing of information." ;-)

I like FF-like materials for the low noise, low handshock. In the selfbowyerin game it can be quite dramatic, the difference. And also in that game having even just a few fps more cast counts for a lot, since in effect you use up your bow, like a battery, with every shot. The more "overbuilt" it is the longer it lasts sure, to the point it's not necessarily relevant. But the more wood you sling (being overbuilt), the slower the bow, the more the handshock. It's a match made in heaven for selfbows.

I'm the kinda guy, although I got my wings clipped a fair bit lately, I got two speeds: off and fast as is legal. I'm the last person to leave performance on the table for a promise of a relatively insignificant amount of longevity. I've shot that Kings Pawn for what, 6 - 8 years, almost exclusively and if it blew up today (I've been rough with it, and modified it a fair bit), I'd feel I got exceptional value. It's had two strings on it, your d97 which is my backup string, and a 450+ (8 strand) I made maybe 3 year ago. I didn't like it with FF. If I'd had a spool of d97 I'd a put back on it. The idea of using B50 for anything but string puffs just doesn't enter into my thinking.

This is why you have so much differences in opinion on this topic. Folks have a wide range of expectations, experiences, knowledge, requirements, what-have-you.

You can safely use FF on any trad bow.The important thing is you have to use fewer strands than you would with Dacron (to allow/match safe stretch of the string) and build up the loops to prevent the thin FF from cutting into the bow.The safest easiest way is to double serve the string loops and the serving area where you draw and contact the bows builder to determine how many strands to use.Theres info on all this in one of the three "Trad Bowyers Bible" series of books.

450+ is 30% Vectran and 70% Dyneema. The Vectran is the cause for concern--I think there's been one or two 100% Vectran, or similar, materials put on the market that caused a lot of grief for the manufacturer.

I hadn't even thought to look at the TBB (I have all three)...but those have been out for several years, and a lot of materials have come out and/or been changed since then.

Using fewer strands so you get more stretch makes sense in a way, but on the other hand that's the reason I prefer HMPE materials to begin with. Seems pointless to me to modify an HMPE string so it will act like a dacron string. :confused0024:

The biggest problems I have with promoting skinny strings are, IMO, a lot of "information" purported about them that just isn't so (i.e., "I had to go up two spine groups because I got so much more speed")--at least not in my experience; and that makes people curious and they want me to make them. I will only go so low in strand count, due to the liability involved. Well, that and my concious--I'd feel awful if someone were to be injured because I made them a string I knew was not safe.

There's been too many challenges put out for folks to prove these things--like Ken Beck's offer of a free bow for proof of a gain of...2 fps, I think? 'Course there was a flip-side of forfieting your bow, or having to order a new BW at retail if you lost. I believe that challenge was out for a full year, with no takers. That says a lot to me.

The reason FF is faster is because of it's thinner/lighter strands so you will gain a few FPS all else equal.Reducing the number of strands also reduces weight increases speed more and allows some give in the string so it will transfer more energy to the arrow rather than over-stressing the limbs causing them to delaminate.

I hate Dacron,
I love DF97 and 8125.I use them on all of my bows including the self bows.
I have found that some bows give better gains than others with diferent strings, and the string maker has a lot to do with the gains.Take 2 identical strings and stretch one to 300# and just let the bow stretch the other one, or stretch it to 50# or so.. The diference is big. Pre stretching is a good way to get the max benefit.
As for failures again I think the string maker has a lot to do with it, particurarly with skinny strings.
Take 10 strands of DF97 and see the loop size in a flemish twist. That is concentrated forces and a failure is more likely to happen, however pad those loops to 16 strands and look at the loops again. The padded loop is a solution I like. It spreads the forces over a larger area. The padding materialmakes no diference, it is just filler to spread the forces over a larger contact area.
Lift a heavy weight with 1/4" rope by bare hands, then the same load with 1/2" rope.
One more point for those that like to compare things. String up your bow and shoot it thru the chrono, now shoot 10 arrows and chrono it again. It will be faster.
So when you want to compare strings shoot 6 to 10 arrows before recording the numbers. The strands need to seat in to be be consistant.
I never bothered to much with real skinny strings, but do have a couple 8 strand padded loop strings I use with 40# limbs. The rest all have 10 strands with 16 in the loops.

Pete