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Bamboo

Vince Marinaro on Bamboo Rods:

from Ring of the Rise

Part 2
January 12th, 1998
"Bamboo, being a natural product like flesh and blood can establish a greater a ffinity with its owner than with any other material. There can be a powerful personal bond between them, and identification, that lets the caster feel the rod is an extension of his own personality. It goes beyond mere pride of ownership.

"This is the romantic side of bamboo ownership, of course, and if bamboo is to maintain its status as a material, it must stand or fall on the basis of measured mechanical efficiency ag ainst any other material. And today, with all its faults, I do not hesitate to say, emphatically, that nothing on this earth is more suited for a given job than bamboo is for fly rods. I say this because bamboo has one outstanding and desirable property not contained in other materials: It has that wonderful property of allowing the caster to deliver a cushioned stroke. This is a priceless quality, or property, that forgives all its many faults. The reason for this lies in its peculiar physical struct ure which is like other grasses and reedlike growths.

"The outer skin is a hard siliceous coat of no value. Next to this is a cambium-like layer with a paperlike texture. Both of these are removed in rod-building. The remainder is composed of two very dissimilar components. One of these is the bundle of long hard fibers mostly concentrated near the outer skin. The other is a soft pithy material that serves as a bond and matrix in which the long fibers are embedded but separate d from one another by the pithy material. The valuable sense outer layer of fibers is not much more than 1/16 inch thick. This is a very fortunate arrangement because the interior of the rod when completed becomes nothing but soft pith, keeping the rod light, and gives the hard outer layer some place to go during the violent displacement of the fibers when the rod is under tension and compression in the act of casting, besides which there are no useful dynamics in the center of the rod. It is a dead ar ea. That is why older techniques of double-building and steel-centering were worthless and actually harmful. In the act of casting the stresses created by bending cause those long fibers to move in different directions sideways, vertically, and horizo ntally pushing hard against the pith which is so soft that it can be cut with your fingernail. That is the cushion against which the hard fibers are working. As a result of this cushion, reaction or recovery from the violent shifting and bending is de layed and dampened so much that the line or projectile is allowed to go smoothly on the way while it is still in contact with the rod tip. What's more, the line goes on its way unhampered by wavy impulses because the tip does not vibrate or react violent ly. That is what is meant by a cushioned stroke.

"It is the closest thing I know to a denial of Newton's Second Law of Motion. To be sure, the reaction is there but it is held back and delayed or softened even from th e slight pressure of the running line. It is remarkably similar to the sudden forward motion of the barrel of a big naval gun, after which it recoils slowly and smoothly against the cushion of a spring-loaded carriage to dampen and kill the vibrations.

"Rod manufacturers have known about this for some time and have been battling to obtain that same beautiful performance with new materials from time to time. My own belief conce rning these efforts is that it is a mistake to reply on homologous or single-structured materials. Nature's plan, in bamboo, seems like a far better avenue of approach.

"That pith that I have been discussing in the split-cane rod is a contradiction in name and function. It contributes to both the weakest and strongest elements in the bamboo rod . When you stop to consider you must realize that the entire structure of that fine instrument that you have used, possibly for many years, is a miracle of strength held together by nothing but a piece of punk. It begins to break down, immediately, with the first cast from a new rod and continues to deteriorate at a pace that is dependent on the amount of abuse that it gets from the owner.

"There are many ways to abuse a rod beyond the limits of adhesion between pith and fiber. I have seen most of them: skull-dragging big fish such as salmon; tugging violently when the fly is hung in a tree, overburdening the rod with heavy lines; trying to retrieve a very long cast, and many others. I have seen a fine rod ruined on one fishing trip. On the other hand, a split-cane rod can last a lifetime with decent use. The li mits of adhesion between pith and fiber are often reached without sign of rupture. In fact, bamboo rods do not rupture unless ruined in manufacture by heat treatment, undersized ferrules, or glue failure. The weak pith prevents rupture. All wood produc ts begin to break on the concave or compression side of a bent piece. The collapse of fibers forms a hard wedge that pushes up against the convex side until the limits of tension are reached and the fibers in tension are rent asunder. The soft pith on t he compression side cannot form a hard wedge to cause such a rupture. That is how the pith contributes, in a negative way, to bamboo's enormous resistance to fracture. But as I have said, many a rod has a broken back even though the exterior appears to be immaculate. Such a rod will no longer cast accurately but will follow the weak side and weave in the act of casting. The same thing applies to glass or any other material, except that there is a difference in the way that the breakdown occurs." VM


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