Just the facts!

A PRIMER ON GRAPHITE FLYRODS!
          Graphite is a fiber composed of from 94% to 99% carbon, and is processed from an organic mixture callled Polacrylonitril, through a heat process with temperatures ranging from 1300F to 4000F for standard and intermediate modulus fibers to as high as 5500F for high modulous fibers. (It's this high heat and energy requirements along with processing costs which drive the cost of graphite.
          The resulting fibers are laminated into a sheet and their modulous typically control the strength and stiffness characteristics of the laminate. For example, the higher the modulus the stiffer the rod, but the strength factor drops off, allowing for a possible higher failure rate, which then must be compensated for by design (i.e. thicker wall or mixture of different modulus fibers or materials, such as boron.)
      The second base material is the matrix or resin and is the binder that contains the fibers and transfers loads to the fibers, the latter being the most significant. Therefore, a low strength matrix or a poor fabrication process will yield a higher product design failure rate, particularly in the compressive mode.


THE IMPORTANCE OF MODULOUS!
          Modulous or more correctly the Modulous of Elasticity is a ratio of stiffness to weight. As you cast, the rod flexes with the weight of the line, storing energy as it flexes. When the motion of the rod stops, the rod reflexes and releases all of its stored energy to propel the line.
          When you increase the modulus of the graphite, the ability of that graphite to store and release energy is also increased. This also increases the speed of the rod when releasing the stored energy, and thereby, increases the line speed that is generated by the cast. Increase the modulus, and you increase the reaction speed and power of the rod blank while decreasing weight.
          Unfortunately, as indicated above, the process of creating higher modulus graphite is a costly one, with the cost of the highest modulus material as high as ten times more than standard graphite, which is then passed along to the angler when he or she buys the rod. For many, including myself, the increase in rod performance justifies the increased costs.
          The higher modulous rods can be somewhat more brittle and susceptable to breakage from impact and breakage which is usually caused by being struck with beadhead flies, or other hard bodied flies, or by striking, dropping or banging the rod on hard surfaces For instance, hitting thte rod racks or a light fixture in a fly shop while whipping the rod back and forth to test the action. Always closely inspect that new rod and entry level anglers might be wise to consider this and select their first rod with a mid-range modulous.
          The rods and blanks on the market with the highest modulous are offered by G. Loomis in their GLX model and Sage in their SP or Graphite IV and a few others. These range somewhere near 65 million modulus. Next down the line is Sage Graphite III found in their VPS, XP, and RPLXi rods. These and the G.Loomis GL4, IMX, the Fenwick Ironfeather and several other rods on the market are in the range of 55 million modulus.
          If you back down a little more to the mid 40 million modulus range, you find a group of rods including the Sage DS-2 or Graphite II, the G.Loomis GL3, Redington Premium and rods with the IM8 and SC44 ratings.
          Yet lower on the ladder is IM7 at 42 million modulus and IM6 introduced in 1986 and still a very popular material, with a modulous of 38 million which is much more lively and lighter than standard graphite at 33 million modulus. This along with the IM6 and IM7, is as high as some rod manufacturers get.
          Most of the graphite used in rod construction is available for any rod company to purchase. However, there are a few rod companies (ie Sage, Winston) which use a proprietary graphite (made exclusively for them) in their rod blanks. By this, they control the modulus, tolerances and quality of the graphite. The rod builders receives their graphite on a big roll which looks much like a big roll of paper. In actuality it's a dark fabric with paper on one side. The materials in this fabric, the way it is woven and the resins on the back of it are all very important to how the rod will perform.


IM-6 -- ALL THE SAME?
        Let' s take a look at a roll of IM-6 material. Lying it paper side down, you can see the material of a rod blank. The top layer which runs lengthwise as the material comes off the roll, is the base IM-6 graphite that runs lengthwise through your rod blank and gives us the modulous of the rod. The next layer we find is called scrim. This is a fiber composed of fiberglass, graphite or a mix (all IM -6 rods are not equal) and runs crosswise to the top layer of graphite or is woven, depending on the manufacturer. This layer adds strength and keeps the linear graphite fibers from separating in the finished blank, thus keeping the walls of the blank from crushing.
          The last layer (not counting the paper backing which is discarded after the graphite sheet is cut), is of resin. The resins are the glue that holds everything together in the finished rod and top companies pay a lot of attention to the formula and process of making their resins. If you get this step wrong, the rod will not perform or last as it should. ( again all IM-6 rods are not equal)
          As you can see, the resin process is a heat sensitive one and even after the rod is made, heat can ruin it. A common mistake folks make paving the way to rod failure is to leave their rod in the car on a hot day. Even the best rod will not withstand the heat in a car's back window for long without damage.


ROLLING A ROD!
          Any way, back to the construction process, Following inspection the graphite is cut into long, thin triangles. This step is critical as the dimensions of the triangle is greatly effects the action and performance of the rod.
          This triangle is then wrapped around a mandrel (a thin metal rod) The action of the rod is greatly effected by the mandrel's shape and the cut of the triangle. Once the graphite is rolled around the mandrel (linear fibers running lengthwise, resins on the outside), cellophane is wrapped around the graphite to hold it together while during the baking process.
Cellophane won't melt, that's why they use it. The graphite covered mandrel is then placed in an oven and baked, thereby liquifying the resins which penetrate throughout the graphite and scrim. The baking time and temperature is critical and part of each rod companies unique formula.
        Once the baking is complete the blank is removed from the oven and cooled and the cellophane removed. The blank is usually sanded to remove the ridges caused by the cellophane. Several manufacturers don't sand their blanks (Scott at one time and may'be still doesn't), leaving the ridges on the finished product as a sort of a trademark. Most do sand the blanks, feeling the resin ridges serve no useful function and only add weight to the blank.
          Next a clear, sometimes colored, finish coat is applied which protects the rod from impact fractures and adds to the aesthetic of the rod. Some manufacturers such as G Loomis omit this step leaving the blank dull since they feel the reduction in flash while casting and reduces in weight makes a better rod.
          From start to finish making the graphite blank used in a rod is a very complicated process. It may be an IM-6 rod but the scrim, the resin, the mandrel shape, the cut of the triangles, the heat of the cure, etc all effect the action of the rod not to mention the wrapping, hardware, ferrule construction and other factors. There is just one Winston IM-6 just as surely as there is just one Sage Graphite IV.

Good Fishing
Chuck Scheerschmidt