Carbon Arrows Weakening In Spine, Over Time

[Whitetail Addict]

I read something online the other day that I'd never given any thought to, but does seem to make sense.

I read so many different archery related articles, that I can't remember where it was, or who wrote it, but I thought I'd bring it up here, and see what you think.

Before I read the article, my first thought was paradox. I wondered if over the course of many shots, the strain put on the arrow as it goes around the riser, may eventually weaken it to the point of reducing spine.

I'm not what you'd call a technical archer. I've found what works for me over the years, and I stick with it, but I do find things like this interesting.

Anyway... The article dealt with target shooting, specifically carbon shafts. The author stated that repeated shots into foam targets, can eventually wear the outside of carbon shafts to the point that it can weaken the arrows spine.

like I said, I don't get too deep into the technicalities of the sport, I'm just an old hunter at heart, but I thought I'd bring it up here, and see what those of you that do, have to say about it. Thanks.

Bob

[The Whittler]

If you have a spine tester you could find out fast enough. Over a 3 to 6 month period shooting the same 2-3 arrows 30-50 shots every day.

That would be kind of cool to find out. I don't have a spine tester so I can't help you. Maybe someone would volunteer, hint, hint. :-)

[Whitetail Addict]

Originally posted by The Whittler:
If you have a spine tester you could find out fast enough. Over a 3 to 6 month period shooting the same 2-3 arrows 30-50 shots every day.

That would be kind of cool to find out. I don't have a spine tester so I can't help you. Maybe someone would volunteer, hint, hint. :-)

That's a good idea. Unfortunately, my rotator cuffs being what they are, 30-50 shots in a day would probably put me out of commission for about a month, lol.

Bob

[Pete McMiller]

My first question would be - what did the author mean by "repeated shots"?  I have shot the same arrows at the same target thousands of times and have not seen any wear at all on the shafts.  They were GT blems (woodgrain) so it certainly would have shown up if it was happening. A few ago years when I was trying to develop my form I know I shot the same arrows at least 10,000 times and in fact still have those arrows.

Without reading the article myself I won't disparage the author but it doesn't sound reasonable to me.  Then again, I don't know everything - that'll come as a shock to my friends, I know        :rolleyes:

[nineworlds9]

I think this article youre talking about might refer to light spine thin wall black carbon target shafts, also, I'd want to see some scientific evidence as carbon fiber is one of the toughest man made materials around.  Higher gpi hunting shafts with any kind of coating I doubt would suffer from this until after 10s of thousands of shots.  I dont think there is a need to get worried.  The only thing I check mine for are cracks.

[M60gunner]

I shoot with some guys that have arrows (GT Trads) that the first 3-4 inches of finish is gone. It does not seem to bother there arrow flight. Of course we are not shooting in competition with fancy target rigs. Not picking on target shooters but some of them are good enough to see the differences. I am not.
I am of the group that thinks all arrows lose some spine after a given number of shots. One reason we like to have a fresh set of arrows for hunting or that big tournament.

[TOEJAMMER]

I would think that the manufacturers of the carbon shafts i.e. Easton, Gold Tip, Carbon Express et al, would have the scientific answer and the data to back it up.

[Whitetail Addict]

Originally posted by Pete McMiller:
My first question would be - what did the author mean by "repeated shots"?  I have shot the same arrows at the same target thousands of times and have not seen any wear at all on the shafts.  They were GT blems (woodgrain) so it certainly would have shown up if it was happening. A few ago years when I was trying to develop my form I know I shot the same arrows at least 10,000 times and in fact still have those arrows.

Without reading the article myself I won't disparage the author but it doesn't sound reasonable to me.  Then again, I don't know everything - that'll come as a shock to my friends, I know          :rolleyes:  

I apologise, I can't for the life of me find the article again, or I'd post a link to it.

Like I said, I read so many different things related to archery, and this kept coming back to my mind and got me thinking about it. It seemed interesting, so I thought I'd post it.

Friction will cause wear on anything in time, but like some of you said, it would seem that in the case of an arrow being shot into something like a foam target, it would take a lot of shots to show any.

Bob

[halfseminole]

It has to do with the quality of the epoxy holding the strands together.  Most carbon shafts are unidirectional, so removing a layer on the outside will allow them to bend further.  Shouldn't be an issue with hunting weight shafts.

[old_goat2]

Maybe, but i break them or lose them way before it becomes a measurable amount!

[kat]

If they do weaken over time; I would be curious as to how much. I shoot C.E. Express Heritage arrows, and I have seen .015" difference in deflection in a given dozen.
I can't tell the difference in how these arrows shoot, so I doubt that I am good enough to tell if the spines are weakening over time.

[Whitetail Addict]

I shoot Gold Tip trads. I'm going to get a hold of them and explain what I read, and see what they have to say about it.

I can't say that I have arrows that I've shot tens of thousands of times like some of you folks, but I do have some that have been shot what for me, is a lot over the years, at both targets and through a bunch of deer as well. Refletch as needed, and they seem to fly as well as the new ones. Then again, I'm sure I'm not good enough to notice any slight differences in spine either.

When all is said and done, what weakening there may be is probably so slight, that it wouldn't make any difference to the average hunter/shooter, but again what I read made me curious.

Bob

[Bladepeek]

As someone with an engineering background, I agree with Whitetail Addict. Whether or not a weakening of spine occurs over time, or over continued flexing during shooting is interesting to me.

I fully agree I don't shoot well enough to tell the difference. I can't tell the difference between arrows with 6% spine tolerance vs 3%. That doesn't mean there isn't a difference.

It's difficult for me to believe that a constant flexing of a shaft with the continuing shock of impact would not have some effect.

Seems it would take at least at least a dozen or preferably more arrows, numbered and very carefully spined when new. Then, after several thousands of shots, measured again. Worth the trouble? Not to me, but I'd be interested in seeing the results if somebody else does the testing    

[Whitetail Addict]

Just emailed Tim Gillingham at Gold Tip. Hopefully he'll get back to me with some data, or at least, his opinion. Thanks.

Bob

[Alexander Traditional]

I think this is a very interesting question. I thought of it a while back,and was too chicken to ask. Glad you called the factory,and it will be interesting to hear what they say. I think it would. Anything else you use that gets flexed over and over like a spring loses potency.

[mangonboat]

Basic engineering maxim is that every structure has a limited number of stress cycles and will ultimately experience end-of-utility failure  when used as intended. The granite and basalt of the Appalachian Mountains used to be over 17,000 tall feet in  places, but these mountains are over 1 billion years old. A carbon, aluminum , wood or fiberglass arrow , when shot enough times, will fail. It's just a matter of how many cycles. The performance curve is probably very flat until structural failure starts at the molecular level and goes downhill increasingly steep from there. I bet the manufacturers can either tell you or give you an educated estimate of the cycle -life of their arrows.

[mangonboat]

I am also guessing that the odds of an arrow experiencing end-of-useful life failure are minuscule compared to the likelihood of external structural damage. One nick from another arrow's tip....

Way off here, but 17,000 feet, fascinating.  My favorite mountain range is the shield of Quetico Provincial Park, I was told it is the oldest mountain range on the planet.  Back to the thread, could UV damage be part of it or just plain old radiant heating from the sun?

[bamboo]

don't forget the flex cycle induced at the target impact--

[halfseminole]

I find this interesting.  Carbon fiber in artificial feet (the "blade" legs) doesn't seem to lose elasticity-they are often replaced because other hardware wears rather than the blade is damaged.  This comes from personal experience working on such.  You'd see it replaced for a better fitting socket or a busted bolt.  

I think it has to do with the quality and type of epoxy.  I know that I could make blades that wore better than iron, but I don't know what the carbon makers use for epoxies.