Allow me to offer a little background of carbon fiber (CF) and fiberglass (FG) and then compare the two, hoping to explain and eliminate some of the misconceptions. Concerning our fishing world, FG became the new state-of-the-art material for blanks in the late1940s and quickly displaced the use of previously premier split-cane bamboo; FG was lighter, immensely less labor-intensive = lower cost, and produced a favorable “feel”. It is no wonder why bamboo was ignored by so many in favor of FG. 25 years later in the early 1970s, the newest wonder fabric, CF began to displace FG in the same fashion; while it was lighter yet and displayed noticeable other performance gains, the cost was quite substantially more and initially available only in unidirectional form = difficult to wrap on a mandrel. None the less, rampart advancements with the newest state-of-the-art CF (the ability to weave it being number 1) almost left FG to the wayside.
Let’s start with the older material first, FG. It is produced by extruding fibers of molten glass (not unlike plate or window glass) under pressure in a controlled environment. Presently, at least two different types of FG are available; E glass and S glass. While there are those who say E stands for Electrical and S stands for Structural, I cannot confirm that, but S-glass definitely has a higher modules of elasticity and hence stiffer. Initially, the fibers were confined in a number of different plastic matrix, polyester (commonly referred to as fiberglass resin) being the most popular; while polyester is still the preferred bonding agent with its lower cost, FG responds very well to modern epoxies as well. With its typically and relatively short pot life (at least commonly available polyester resins), quality epoxies with varying-time catalysts can prove to be invaluable when producing involved FG composites.
Enter CF. While the production of CF is much more involved and scientific than FG, it is basically carbon atoms bound together in long chains; do not expect me to elaborate as I am admittedly unqualified. Originally, CF was manufactured from Rayon but presently, about 90% is manufactured using the polyacrylonitrile (PAN) process; again, do not expect me to explain further. The original manufacturer was probably (but unconfirmed) the American-based Hexel Industries, with Toray (Japan), Axiom, Teijin and Misubishi following. While Toray seems to be the buzz-word these days, I would like to believe Hexel is still at the forefront of CF development. The result is astonishing hence why it is rightfully the modern-day wonder fabric. It’s modules of elasticity is considerably higher than FG making it much stiffer; this equates to CF structures requiring less material to support the same load with an overall weight savings. CF’s attributes for blank construction does not stop there; it’s high modules (density/stiffness) also affords more precise transmission of vibrations (sensitivity) and higher/faster dampening of oscillations (recovery) of the rod tip after a cast. Again, and in retrospect, it is no wonder CF has displaced FG for blank construction. In many cases of blank construction, CF might appear to be the best choice but further enlightenment is required for the ultimate choice of blank construction.
Per volume or displacement, CF weighs minimally less than FG. It is the simple fact that with CF’s higher modules/density/stiffness, less material is required to support the same load which equates to less material and thus ultimately lighter overall weight. Without a doubt, 75% of the custom rods build will benefit from the attributes of a CF blank with their inherent weight savings, smaller diameter, sensitivity and rebound dampening. But strength has yet to be addressed.
“Strength” is a relative term and can be observed from different perspectives, and possibly ultimately the jest of this post. One contingent may consider “strength” as what it takes to make a structure catastrophically fail while another views it as how much the structure can repeatedly endure before failure; they are not the same. For comparison, consider the difference between a carbide drill bit and a high speed steel (HSS) bit. Because the carbide bit is much harder and stiffer than the HSS bit, it will drill harder materials and its stiffness, resistance to flexing, will drill a straighter hole, hence why carbide is the preferred material for machining on a mill or lathe where the part and bit are held very rigidly. But carbide is not recommended for hand-held drilling where the slightest movement of the part or bit will cause the bit to easily snap in two. Viewing the same two bits in another way, clamp both bits in a vise; tap the HSS bit with a hammer and it will flex and return back to straight where the same tap on the carbide will easily snap it in two. With its inherent higher modules, stiffness and consequent yield-point, one could argue CF is stronger. But that greater stiffness inherently makes it more brittle. On the other hand, one could argue the toughness/ability of FG to yield makes it stronger. There is a reason why so many heavy, offshore rods continue to be constructed of FG. While not a mood-point, both needs to be considered for each rod application. I suppose my intentions are for all to not rule-out FG; correctly applied it can be as beneficial as CF in certain applications. From simply a personal perspective, I enjoy the Fish-Fighting-Fun-Factor of a full-flexing FG trout rod over all the CF counterparts in my arsenal, but that is just my opinion. Yes, I build CF rods also. While I will not argue with those who say FG rods feel “sloppy”, I consider the term harsh and unjustified while thinking of them as full-flexing with the ability of possibility casting very light lures a further distance.
One way or the other, the dynamics of FG and CF differ; it is up to the educated rod builder to utilize either to the best advantage; do not rule FG out simply because it is not the main-stream present-day wonder fabric; it could very easily produce a wonderful rod!
It only seems logical to expect another new wonder fabric (Unobtainium) to be developed in the probably not too distant future which may replace CF just as CF and FG displaced their predecessors. Who knows, maybe the new material will allow us to wad-up the rod and stick it in our pocket and then pull it out and let it unfurl when time to fish!

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

I just built a 3 weight, CTS fiberglass fly rod. This rod recovers from vibration as well as my Winston BIIIX. The Winston is a CF rod with moderately fast action, which is the same rating on the CTF FG rod. Both will lay a dry fly on the water delicately, and both are soft enough in the tip to protect a light tippet.
They are both well balanced as well. My issue with CF is, as you mentioned, that it can be brittle. It's tensile strength is greater per unit weight, but it's shear strength is not as good as is fiberglass. I once pulled in a very large King Salmon with a $15 FB rod purchased at a sporting goods store. The rod was made for panfish, and brookies. The rod didn't break, which amazed me at the time. I know from first hand experience tough a glass rod can be. And with modern wrapping designs, they are nearly as powerful as their CF cousins, but I think a bit tougher, if a tad bit heavier. I love the idea of composite rods, with the blank construction using both CF, and FG in the parts of the blank that the fibers are best suited for. I know that both North Fork Composites, and CTS make composite rods. There are probably many others as well.

I think carbon nanotubes, or graphene will be the next big thin. The materials are super lightweight, much stronger than the strongest fibers we now produce, are flexible, and have amazing tensile, and shear strength. Only time will tell.

Tight lines and frisky fish

RJF

Oh and remember the Boron rods also. Mark excellent article you posted, Like you say they both have a place in the sport, Plus it gives us rod builders more tools in our arsenal.

Robert,
Thank you for taking the time to reply and not only offer your observations and opinions, but informing me of “graphene” which is news to me; you are obviously well informed of the composite industry and I appreciate the information. By the way, you explained it better than I did with your comment,”its [CF] tensile strength is greater per unit weight than FG, but its shear strength is not a good as is fiberglass” = well said.
I continue to be perplexed as to how and why the rod building world has bastardized the term “composite” and confused its members by implying it is a combination of different fabrics in one structure. In the true sense of the word, a composite is simply a single (or combination of) reinforcing fabric (such as CF, FG, Aramid, cotton, or even graphene) within a matrix of plastic (usually epoxy) to produce a fiber reinforced plastic (FRP). Thus a part made entirely of FG is a composite as is one made with only CF as well as one made of a combination of all the reinforcing fabrics. Originally, the term “composite” referred to a composition of fibers and a binder (matrix), not necessarily a combination of more than one fiber. Maybe I am being nit-picky but it is none the less baffling to me.
A FG rod will usually be heavier than a CF counterpart when “dead-lift” is the only concern of strength. However, when ultimate toughness is the main concern of strength, the additional plies of CF required would offset any weight savings and consequently the rod would be excessively stiff; hence why the rod builder who understands the differences can ultimately afford a superior specific rod.
Hopefully others will chime-in and enlighten all of us with their experiences, observations and opinions; I am here to learn.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

John,
Thank you for your input as well. While seeing ads for boron rods, I know dittly-stink about it/them. Can you, or anyone else for that matter, afford a little more insight as I am quite curious.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

boron is a metalloid that is rare in the Earth's crust. It is mined in it's most abundant compound form, borax. Boron is used in high strength ceramics, and where structural strength can be improved by the element. It has a much higher modulus than carbon and so seemed perfect for the fishing rod industry. However, boron filaments are expensive, and due to its stiffness, hard to wrap around a mandrel, especially the narrower portions of the mandrel. It was at one time used by Sage, Ross, and Fenwick, among others, in their rod blanks. Initial high cost, and difficulty in using it, especially in mass production, rods doomed it. Only R.L. Winston still uses boron, and only in the lower section of the blank. It adds stiffness beyond what carbon fiber is able to, allowing the use of less CF. This improves the power of the rod, while making it lighter. It allows the blank to have great power, but maintain a moderate, to moderate fast action, while creating a light weight rod blank. I built on 7 weight, 9 foot Winston BIIIX, and it is a truly great rod. It does exactly what it is supposed to do.

As far as graphene in rods, there is one company using it - [g-rods.com] Graphene is an atom thick honeycomb lattice of pure graphite. Though it is still an expensive material to obtain, it has amazing properties. It is 100 times stronger than steel, and is highly flexible, and virtually transparent. it is a two- dimensional substance.. When two sheets of graphene are bonded together, it becomes very stiff, and strong enough to stop a bullet. So, imagine a sheet of highly flexible graphene wrapped around a mandrel, ore over spiral wrapped CF on a mandrel., with a second layer then wrapped and boded to the first, then with a layer of CF filaments running from butt to tip, all bonded in a micro-silica resin. Can you see the potential? The cost of graphene is coming down as its unique electrical, thermo, and structural characteristics make it one of the most sought after materials on the planet. When graphene production costs get low enough, I believe you will see graphene used in many, many different applications, including fishing rod blanks.

There is one more super material that I know of, used in fishing rod blanks, Kevlar. I've only seen it mentioned one time. But i know Kevlar is used in body armor, vehicle armor, motorcycle helmets, and bullet proof shirts. It too is 5 times stronger than steel. There are several types of Kevlar, some with great ballistic properties, some with a very high modulus, and others with great flexibility, and fatigue resistance. Though i haven't owned a rod with Kevlar in its make up, I have owned multiple motorcycle helmet made with the material. One time, while dirt biking, I flew off of a hidden cliff, to fly at least thirty feet befor colliding with the downward slope of ground. The bike flew further,, and fortunately landed in sage brush, which prevented major damage. While tumbling ferociously, my head struck a large rock. Thanks to the helmet, iI didn't even feel it. I was uninjured. The problem with Kevlar is that ultra violet light degrades it, and so for outdoor use, it must have ultra-violet protection.

So that's what I know about exotic materials that are sometimes used in rod blanks.

And just so ya know, I know much more about all kind of cooking. Send me an email if you want to learn virtually any cooking technique, or recipe.

Tight lines and frisky fish

RJF

For a very short period of time, there were rods and blanks made from Kevlar. It was too heavy to allow for much in the way of a responsive rod and was quickly phased out. The rods were tough, but heavy and slow.

..............

Robert,
Thank you for the in depth reply; you have been a wealth of information.
You are correct in that there are basically two different types of Aramid (commonly referred to as Kevlar); para-Aramid and meta-Aramid. While both are quite similar molecularly, para-aramid is intended for structural applications while meta-aramids are designed for ballistic and thermal (such as firefighter suite) applications. Both respond very well in tensile strength, thermal stability and abrasion resistance but, as you mentioned, suffer from UV degradation. Of the three major composite fabrics, FG, CF and Aramid, Agamid is by far the toughest, mainly due to its abrasion resistance which relates to the molecules resistance to being separated. Aramid fabric is typically priced between FG and CF.
As far as Aramid used for blank construction, it would certainly blow-away either FG or CF from a toughness perspective. I have been surprised to not find it used for heavy offshore blanks. I purchased a Phenix Black Diamond Hybrid due to inclusion of Kevar for that very reason but there is no visual indication of it existing. The only reason I can see is that most structural epoxies do not bond quite as well to Aramid as they do to FG and CF. As with nylon, Aramid is prone to absorbing moisture as well. Weight would certainly not be a factor as an Aramid rod would be considerably lighter than one of FG, at least for offshore applications.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Zentron fibers are showing up in some fishing rods. It is used to make composite blanks with either S glass or carbon fibers. Supposedly makes the blank much tougher, and gives it some other unique properties. NFC uses this material in their Delta and Neo X-ray blanks, and Epic uses it in their Fast Glass fly rods. I know very little about Zentron except that it exists.
Norm

I'm reading these posts during a break from wrapping silk on a bamboo blank. Makes a fellow feel out of step and a little bit - old.

I did some research on Zentron. It is a thermoplastic that has longer fibers compared to but not nearly as brittle. carbon fiber. According to the manufacturer, this makes it superior to CF as it is comparably ngth, and toughness is supposed to make it easier to work with in pre pegs, and less expensive as well. Coupled with fiberglass. with resin, tests show that the resultant blanks are lighter, with better oscillation recovery, greater sensitivity and resistance to collision damage when struck against hard object. According to the manufacturer, this makes it superior to CF as it is comparably strong, Here's the link from where I got my info - [www.nasampe.org]

The Epic link where they talk about using Zentron - [swiftflyfishing.com]

There are other, more technical articles tobe found online. However, unless you are designing high strength ballistic armor, helicopter rotor blades, pressure vessels, or dishing rod blanks, or are simply a curious person, like me, who wants to learn about everything, they aren't really useful here.

Zentron just may be the next big thing. Thanks for bringing it to my attention.

Tight lines and frisky fish

RJF

I thought it was a fiberglass imported from India..lol..

My digging showed that Zentron is a silica based glass fiber developed by Owens Corning here in Ohio. Another manufacturer markets a similar product as S-2 glass and is a bit cheaper to produce. It has modulus of elasticity ratings about 10% higher than typical S-glass. I would welcome the. Material in my crank bait rods but it is not going to supplant carbon fiber in the fishing rod industry.

The material certainly has a future in glass composites.

does anyone make a 100% carbon rod? aren,t they mostly a blend with fiberglass in the tip section and graphite in the butt or lower modulus carbon in the tip..Mark like you i have gone back to glass rods..better fish fighting qualities and i like the slower gentler actions..getting old i guess..lol..even for fly rods, i find that using glass rods under eight feet i can use regular ceramic guides and not the more costly titanium guides for less weight..this is for bass fishing not trout in streams..on the spin or cast rods i regain the sensetivity of carbon by using braided line on my glass rods..all my glass rods are E-Glass which has the slowest action and response that i like..

No one makes a 100% carbon rod, you need a resin to keep it together, but there are some that make rods without glass. Hydra makes a line of blanks without a glass scrim fiber. The old RX8+ blanks had no glass in them. I believe they used a paper scrim of some sort. I think I've read some of the old Loomis blanks, likely the GLX were without glass. In the late 90's I had a Mitchell K-Mart special rod that had 100% graphite painted on the blank. I highly doubt it was, but was a surprisingly nice rod for its price at the time.

"100%" is a tricky way to word things, but some have for advertising purposes.

What most rod builders and manufacturers are referring to when they say "100% carbon" is the fibers (main and scrim) used to make the blank. Not the overall percentage of total blank make up that would also include the resin, coating/paint, etc.

............

Thank you to Norman, Donald, Robert, Ben and Joe for contributing to and continuing this topic of blank construction. All of you have supplied valuable information regarding relatively unknown fabrics which could possibly, and may be, employed in the construction of blanks; Boron, Graphene, Zentron, S-2 Glass, and still my favorite, Unobtainium.
In CF’s defense, if Zentron/S-2 Glass exhibits a 10% gain in modules over typical S-Glass, it would still fall short of CF in that respect; and that respect is extremely important from a vibration sensing and dampening perspective.
After viewing Robert’s second post on this topic, my initial observation is that Graphene may be a two-sided-sword; as with most aspects of life, there are checks-and-balances, pros-and-cons, can’t get something for nothing, universal mortal rules. The greatest tensile strength of ANY fabric composite will be achieved when the fibers/molecules are aligned parallel/inline with the force applied. Stating the obvious, the shortest distance between two points is a straight line. Basically, the higher the modules and length of the fibers = the higher the tensile strength/yield point the structure will be able to achieve. If Graphene exhibits a “honeycomb” structure/nature, this would eliminate a straight-line, parallel path for the implied forces to follow and ultimately produce a structure which would be less stiff. But, as Robert offered, that structure may provide a more resilient/ less brittle nature. I am certainly not arguing that Graphene has promise; quite the contrary as I am indeed intrigued from my modest knowledge of physics and the composite industry.
All said and done, I am still curious as to why Aramid (Kevlar) has been basically excluded from blank construction. While it is notoriously and virtually impossible to cut with common cutting tools (which exemplifies its abrasion resistance), and certainly not applicable to all rods, I am confident it would produce the ultimate toughness for heavy (but lighter weight) offshore blanks!

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Donald,
Do not despair or sell yourself short! The entire rod building world is blessed with the remaining veteran builders, such as yourself, who continue the old-school traditions for the benefit and enlightenment of all. While a modern CF rod (be it fly, cast or spin) may be the ultimate in precision, vintage-style bamboo or even FG rods can produce the ultimate Fish-Fighting-Fun-Factor!!! I am a believer!

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.