I had an interesting discussion with a friend of mine the other day and thought I would put the question that arose to the members of the board.

My friend is a striper fisherman (fly rods, San Francisco Bay) and also a tennis professional. He states that his composite tennis rackets have a definite life to them. He says after some duration of use, the racket becomes "dead", at which time re-stringing does no good. When they get that way he replaces them.

The question is does the composite material in fishing rods fatigue over time, not necessarily to the breaking point, but to a point where the action of the rod changes noticeably?

Walt Natzke
Ripon, CA

Great question, Walt ! I'll be vary interested in the replies. Just got off the Delta Friday and the only noticeable fatigue was in my arms and shoulder.

I have several rods at least 10 or 12 years old, to me they seem pretty much the same as when I got them. The newer rods seem to be better made, but I am one of the 95% that could not really tell the difference in subtle differences. I only fish once a week, due to work demands, sometimes not even that. I think tennis players generally place a lot more repetitive stress on the racket than I will ever place on the rods, 'cause they play tennis a lot more than most people fish. Not sure if any studies have been done. John

The fatigue life of a graphite fishing rod is so long that it would be extremely rare that any fisherman could possibly use one enough to see any noticeable difference in power or stiffness even over many, many years of hard use.

Older glass rods with phenolic resins, however, had a much shorter fatigue life and some fishermen that used them for casting heavy weights found a noticeable difference in power in just a few seasons.

This question has been covered here in great depth previously. Do a search and see what turns up.

If you want to try an experiment, you can run a CCS ERN measurement of a new rod and then do the same a few years down the road and see if any measurable difference occurs.

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I don't believe that tennis racquetts change with use unless the use includes striking the ground with them, either from errant strokes or throwing them. I play a lot of tennis and have never heard of anyone mentioning this. I recently played with my 6-8 year old racquette while having my newer one restrung, and it didn't seem any worse than I remember it, and in fact, I was impressed by how good it felt compared to my newer one.

I've never felt that any of my rods have changed. (all fresh water use).

One of the commonly recognized advantages of graphite composites is the very high fatige strength, approaching the ultimate strength of the material. One of the disadvantages is its brittle nature.

I would be very surprised if anyone could prove that the modern graphite rods change with use.

Thanks for your input.

Tom, I did some searching prior to the post, but the search terms "rod fatigue", "fatigue", and others similar returned very little results. I must re-think my queries.

Your mention of fiberglass got me thinking. I have a 25 year old 3wt Winston Stalker that I have used very consistently. I recently re-built it and while I had it stripped down I ran the CCS on it and it came out as a ~1.7. I'm not sure this is inconsistent with the original value, not having tested it back in the day, but it sure was a surprise. Needless to say, the rod loads very well with a 3wt line!

Michael, as for the tennis racquet (thanks for correcting my spelling), my friend is an instructor and teaches on average 25 hours a week. I am not doubting your experience, but I would expect that my friend puts in a lot more time with his racquets than the average player.
In addition, I would think that the affect of thousands of high speed impacts on a composite frame, albeit through the strings, would be much more significant than the consistent strain on a fishing rod. This is not to mention the constant inward pull of the strings themselves.

Walt Natzke
Ripon, CA

A rod with an ERN of 1.7 should indeed load very easily with a 3-weight fly line.

I don't want to start comparing sporting goods implements with aerospace components and frames, but carbon fiber excels at providing an extremely long life which isn't prone to early or significant fatigue even over many decades in some cases. Mere "thousands" of cycles aren't going to affect such composites in the least - you'd have to start talking about hundreds of thousands or even millions (and this is compounded by how much stress we're talking about). But I have no idea what particular material your friend's racquet utilizes nor how many "hits" he makes in the time span you mention. All I can tell you is that you're highly unlikely to find your graphite rods losing any power or stiffness over many, many seasons of hard use.

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Tom Kirkman Wrote:
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> All I can tell you is that
> you're highly unlikely to find your graphite rods
> losing any power or stiffness over many, many
> seasons of hard use.

And that is exactly the information I was looking for.
Thanks again!

Walt Natzke
Ripon, CA

I seem to remember an advertisement from the years when graphite rods first appeared. They were comparing the new graphite rods to the older glass and bamboo. I am going by an old memory stored in a much older brain, but I think they said bamboo was good for 15 to 20,000 flex cycles, and glass was good for some 60,000 flex cycles. Graphite was rated at above 100,000 cycles. I have no idea what they were calling a flex cycle. I can tell you that at the time I was building on Fenwick Glass blanks, LCI, Lamiglas, Winston, and later Talon graphite blanks. This might have been in one of the old Dale Clemens books. I can't remember where I read it, just remember reading it years ago.

Mike Bradfrod
R.M.B. Fishing Rods
Nampa, Idaho

Long rambling post, read at your own risk.

I have no idea about any other sports equipment and doesn’t really interest me however the blank thing is a bit intriguing. Not sure if anything could be “felt” as in a loss of power or difference in response however I suppose fatigue leading to failure can arise from several factors such as use/abuse, material and probably more importantly design. Maybe some slight loss in power or change in action etc. would occur prior to actual failure but I doubt it’s anything measurable. I have several favorite rods that I have “retired” from use, a couple each in s-glass & graphite/composites and one in e-glass. They were my favorites and I used them quite a bit but learned years ago that when they showed visible signs of deterioration that they would eventually break. Being favorites I chose to hang them on the wall rather them use them till the end. I have had this happen on blanks from several different manufacturers so I don’t think it’s an isolated issue.

The very first custom rod I made was used for everything in salt water from inshore bass fishing to tuna, sailfish and one marlin (was rated 15-30# line l think). Was S-glass sabre blank, loved it until I saw some marks below the surface in the upper third of the blank (many years later). Eventually the number of these spots grew and one day I was setting the hook on a small fish and the tip collapsed right where the spots occurred. Same thing happened to another of the same material blank but different models. When it spread to a stand up rod that I caught my first tuna over 100# on I decided to retire it to save it from its eventual demise. I switched entirely to e-glass after that but encountered it in other blanks in different materials including graphite. Now when I see these spots where the rods shuts off I know it’s only a matter of time. While we(family & friends) fish hard with some rods landing literally hundreds of fish over the years I cannot blame it on manufacturer defect but it seems that the longer I have the rod in service the more likely this is to occur. In the past I have also found newly constructed “blanks” still in the plant that can be deflected to produce these white spots which eventually grow in number and size until the blank breaks. Usually, changing the patterns or not over-sanding has eliminated the immediate issue but I often wonder if in time, the same type of delamination will occur. I always wonder how many people have this happen to them and if my “usage” increases the percentage of it happening to me.

Here’s what I was thinking while reading this topic:

1. I wonder if the blank becomes weaker, not in actual strength but in power as it goes through the process? Would seem likely, but probably not measureable or noticeable.

2. If material has a life span or blanks have a life span of deflection cycle counts etc. it must all be changed by function, design and so on. Like if I tend to “high stick” my rods more than others or use light fast action blanks for downrigger applications…... Thick walled blanks or slower actions…..

3. Remembering back, at one time I had regular access to a blank breaking machine totally enclosed for safety of course. I was able to watch blank after blank breaking to check out the process as it happened and average strengths etc. Notable to me was that the angle at which the blank was mounted made huge differences in the deadlift capability however often action was directly related to these results as well. Also if the deflection was held, in time the blank could come apart even after it initially lifted well.

4. I wonder if there is something to the new nano sphere resin systems creating a reduction to this type of event from occurring. It was explained to me that the spheres add strength and reduce micro fractures from enlarging causing failure. I saw test results that were impressive and blanks that broke abnormally when deadlifting significantly more weight.

5. Why the heck do I break so many rods? Oh yeah, testing. Putting it into perspective, I am only talking about a dozen or more(not all broken) out of hundreds over 30 years of fishing fairly hard. Now I try to keep my rod accumulation down to around 100 at a time but I used to collect quite a few.

I know it’s a long post, sorry to waste your time if you don’t find anything here interesting.

Darrin Heim
American Tackle Company

Great post Darrin. There are many questions I could (and many I would like) to ask. Instead I'm going to throw out an "idea" and see what everyone thinks. I'll need to make an analogy of sorts so bear with me.

We grew up in an age of steel. If we have a load bearing member we know it will sag a little under its own weight and will sag more as load is added. However all is well until we load to a point of permanent deformation. By that I mean the unloaded beam will not return to its normal place.....it is kinked/bent/etc. At this point we know we overloaded things and try as we might to right matters it is compromised.

I'm going to suggest rods (composites) are a little different in that an overload doesn't deform so we are lulled into a sense that all is well. Instead it is a little like our own body in that we can overload and abuse a number of times in our early age, but eventually it catches up. I don't see repetitive stress as a bunch of events that have no effective until it rears its ugly head. I see it as a slow and steady death fiber by fiber until the whole is weakened to the point where failure occurs when asked to perform at normal (or peak) levels.

Many desire CCS numbers from rod makers. I desire to know what is the max dead lift I can expect without causing long term harm. I should inquire but I have never mustered the courage to ask point blank. As you know, the light tackle salt water game fisherman can push their equipment to the limit. At that same time these fisherman are also great judges of the limit they are pushing the equipment to and have total control over those limits. Would you have fished those Sabre's with 2#'s less drag, or a different line class, if it equaled lasting forever?

Russ in Hollywood, FL.

Graphite rods do have both an elastic and plastic range. The former is quite broad while the later is sudden and rather narrow. Going from the elastic to the plastic range generally results in sudden failure. That plastic range is just very narrow where these materials and structures are involved.

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Modern aircraft make increasing use of graphite components. I think rod builders originally "borrowed" graphite technology from the aerospace crowd. Aircraft parts are subject to constant, repetitive, and sometime harmonic distortion. I have never heard of a graphite component in an aircraft suffering stress fatigue, although it may happen. At any rate, the graphite used in rod blanks and airplanes is apparently quite similar. The environment faced by aerospace graphite parts is much more severe than that faced by rod blanks. If aerospace graphite components do not exhibit much stress fatigue, crystalizing, or loss of elasticity it seems likely that fishermen have little to worry about their graphite blanks.

There have been airline part failures, but the one I'm familiar with was due to delamination originating from the attach points (Airbus A300 tail sections) This doesn't really apply to our rod structures.

Great discussion, since I just broke my switch rod last weekend. Overloaded I fear with a sink tip and weighted fly. Broke just below the ferrule at the top of the second section on the male side. Now I get to practice repair. :-)

Terry