What is the true story about high modulus graphite being more sensitive to impact failure. I have a lot of stories about rod tip fractures where the "better" the rod the more susceptability to fracture. Thanks.
Graphite composite versus fiberglass
What is the true story about high modulus graphite being more sensitive to impact failure. I have a lot of stories about rod tip fractures where the "better" the rod the more susceptability to fracture. Thanks.
Ray,
My guess is that this question would be difficult to answer for even a plastics expert. You might get an answer for a test sample subjected to what is called an Izod test for either knotched or unnotched samples. But this would mean little in the real world. Things like resin type, surface treatment, scratches, section, reinforcing material (graphite or glass), age, temperature, scrim type and angle, load application, and much more would influence the outcome in an acural rod. But I bet, in the real world, whatever breaks a glass reinforced rod would most likely break a similar rod with graphite reinforcement with all other items being equal. I would be careful with both and if I broke it, I would blame it on me rather than the reinforcement type.
Bob
Speaking of breaking rods, a friend of mine is a die hard bamboo rod person. He owns a number of boos, several made by the same person who made one for me. Anyway, my friend was at a show last year and someone was selling bamboo rods. He asked if he could cast one of them. He likes to and can cast a lot of line (he cast 90 feet using my rod and did so easily). So, he stripped out a lot of line and started false casting and broke the rod. The seller supplied him with an other rod, (bad mistake) and my friend also broke that rod when he had a lot of line out. Obviously the seller needs to make a better bamboo rod.
Larry ---sagefisher---
An old article on boo vs graphite.
http://www.hatofmichigan.org/uploads...romthepast.pdf
Bob
Oops.
I think I found a mistake in Harry’s paper.
From Wickapedia "Toughness can be determined by measuring the area (i.e., by taking the integral) underneath the stress-strain curve and its energy of mechanical deformation per unit volume prior to fracture. The explicit mathematical description is:
Energy/volume= the integral from 0 to failure of σ dε
Where ε is strain a σ is stress
Another definition is the ability to absorb mechanical (or kinetic) energy up to failure. The area covered under stress strain curve is called toughness.
If the upper limit of integration up to the yield point is restricted, then the energy absorbed per unit volume is known as the modulus of resilience. Mathematically, the modulus of resilience can be expressed by the product of the square of the yield strain times the Young's modulus divided by two."
The curves shown by Harry are wrong because he assumed the failure stress is equal between the different modulus’s. It is not.
E.G. Do the math and the IM6 the Modulus of resiliance is essentially equal to the S glass. So the lower modulus does not have a theoretical advantage as stated.
Last edited by Bobinmich; 11-16-2011 at 01:37 PM.
I have only broken two rods. One when I slipped and fell on some rocks. I had not yet learned to sacrifice my body for the rod...Originally Posted by sagefisher
The other one was an Orvis Silver Label 4pc 8wt rod. I was lawn casting it and it broke just above the middle ferrule. The ferrule was tight and the break was about an inch above where the butt section would have reached, so I chalked it up to a manufacturing defect. The rod was replaced without a problem. Defects do happen and it is good to have a good warranty when they do.
Ted
Ted,
I broke a 9 wt. Silver Label in exactly the same way at exactly the same point. I think it is a design flaw in that series rather than a manufacturing defect.
Bob
Bob,
Thanks for the info and idea that it was a design flaw in the rod. I was really surprised when the rod broke and have never really felt the same way about Orvis rods since. The new Hydros and Helios rods are getting great reviews though. A friend used the replacement Silver Label rod on a multi-day float in Alaska to catch numerous silver salmon, so the replacement seemed ok.
Regards,
Ted
Ray,
I seems you and I have come to the same conclusion cheaper rods are more foregiving of rough handling that higher end rods. I don't know but have thought perhaps there's more resin and less fiber in lower end rods and resin is tougher, but does not have the desirable qualities, of fiber. Not being given to following the development of the technology of fishing rods, etc., I wonder if there has been much development in a stronger resin to go with the higher performance fiber and better protect them.
Want to hear God laugh? Tell him Your plans!!!
I think there is some variant of "the cockroaches will always survive" law at play here. Back in my younger days, when I spent a bit of time working livestock, I usually wore jeans and t-shirts. (Actually two pairs of jeans, to protect against getting kicked.) My "nicer" t-shirts got ruined quickly. I bought a bunch of the most unasthetic t-shirts the campus bookstore had to offer (and UT Martin had some ugly t-shirts). They were worn hard but not worn out. I still have the ones I didn't gratuitously discard. So it is with cheap fly rods. (I still have all of them, too.)
Ed
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