BORON: FROM SCOURING POWDER TO FLY RODS

From Piscator no 109, July 1982

By Don Phillips

(Don Phillips has justifiably been called the "Father of the Boron Rod", for he did the pioneering stress calculations and holds patents for solid boron and boron hybrid fabrication. His restless search for excellence, the fact that he produces his unique rods at home, reminds one so much of an earlier master rod builder that one might be forgiven for calling him the "Everett Garrison of the Space-Age Fly Rod". We welcome his contribution: Ed Herbst, Associate Editor, Piscator.)

Although boron is just beginning to substantially penetrate the fishing rod market,   fibres of this material have been available to the world aerospace industry since the mid-1960's. In this period of my professional career I was directly involved with converting the process for making boron fibres; scaling up a research activity to a production operation.

Don Phillips making one of his solid boron rods in the early nineteen eighties.

Boron is one of nature's fundamental elements, found most plentifully in the compound borax, which has been mined from near Death Valley in California, U.S.A., for about a century. Borax, technically known as a hydrated sodium borate, is a common scouring powder and cleansing compound, but it can also be processed to form boron trichloride, a compound used in the U.S. chemical industry.

Ultra high-strength fibers of boron are produced by chemical vapour deposition, wherein boron trichloride gas is passed over a very fine, electrically-heated tungsten wire. Boron fibres are now being produced in continuous lengths in several different diameters by Composite Technology Inc., in Broad Brook, Connecticut, and by AVCO Speciality Materials in Lowell, Massachusetts. Boron fibres have exceptional physical properties when used in composite structures because of the higher fibre strength and stiffness and the extremely intimate bonding that occurs between the fibre’s corncob-like exterior surface and the surrounding matrix material.

Long before I had ever heard of boron, I was a dedicated fly fisherman, wading the streams of New England in search of wild trout. The application of boron fibres to fly rods seemed a perfect match, and in January J972 I began a personal commitment to develop boron fly rods by combining my engineering and fly fishing skills. The following ten years have been exciting, hectic, frustrating, and at the same time rewarding.

Don Phillips has written the definitive book on fly rod design with a specific emphasis on rods made from synthetic materials.

All the manufacturers who said it couldn't be done are now doing it themselves. I believe that they have only scratched the surface of boron's potential for fishing rods.

Boron fibres are used by most fishing rod manufacturers in a manner very similar to the processes involving graphite or fiberglass rods. In fact, most boron fishing rods actually incorporate more fibres of graphite or fibreglass than boron. Essentially, all of these processes involve the wrapping of a resin-impregnated fibrous tape pattern over a tapered steel mandrel. After oven curing the mandrel is removed, resulting in the conventional hollow construction. All-boron construction is difficult in hollow rods because this extremely stiff material must be used sparingly in sections requiring substantial flexibility, such as in rod tips. The resulting thin wall sections have a tendency to collapse under high bending stresses. The mixing of other, less stiff fibres permits a thicker wall section with less fragility, while still taking advantage of boron's exceptional attributes of strength, stiffness and hardness. Since starting my experimentation in 1972, I have employed a solid construction. Initially, this approach was for lack of access to expensive steel mandrels; however, the smaller diameter solid rod does reduce fibre stresses, lowers wind resistance and eliminates wall collapse due to bending or lateral crushing.

Construction of my solid boron fly rods involves the lateral wrapping of a boron- reinforced epoxy tape pattern around a permanent boron fibre mandrel. The tape contains hundreds of parallel boron fibres, all running the length of the tape pattern. The blank is cured in a high temperature oven, under tension, until the epoxy has hardened to its maximum strength. In this unique method all fibres remain exactly parallel to the central mandrel; a configuration which is the most efficient for achieving bending stiffness and for minimizing residual fibre stress after curing. Hollow tapered fly rods cannot achieve this parallel feature. Although I consider these rods to be developed, I am continuing to experiment and improve them. A few cosmetic details have yet to be perfected, and these are currently occupying a significant extent of my experimental effort.

The butt section on the 9 foot 2/3 weight nymphing rod that Phillips made for Ed Herbst. This rod is now being sold through Craig Thom at the Stream-X fly shop in Cape Town

Other manufacturers have been reluctant to follow my method of construction, because the large amount of boron and the extensive hand labour would result in a selling price which only the wealthy can afford. I operate a one-man shop in my basement and this low overhead approach and philosophy permit me to make these rods available at competitive prices.

In spite of heavy pressure from my customers, I have to decline all requests to make fly rods longer than nine feet, or heavier than for 6-weight lines. My experimentation has clearly shown that the solid construction results in too much weight and insufficient crispness of action as the rods get longer and more powerful. There are competent rod manufacturers who are capable of providing satisfactory all-boron rods in these longer lengths and higher line weights, using hollow construction.

Even though the 9 foot solid boron rod was made in 1982 its tip is thinner than the tip of the Sage TLX-F 000, currently the lightest line weight fly rod on the market

Boron is truly a high performance fibre that has significant potential for the fishing rod industry. Unfortunately, there are several financial factors that may limit the wide spread use of the fibre over the near future. First, boron has a current price of $250 per pound, many times the price of graphite or fibreglass. Second, the uniquely high stiffness and hardness of the fibre make it totally unlike any existing material; therefore, automation (to reduce costs) will itself be very expensive. Finally, the structural properties of boron are such that a certain amount of sophistication is required to design each rod, so that the advantages of boron are most fully utilized, and so that sufficient structural integrity is maintained.

The all metal ferrules on Ed’s Don Phillips rod

All of these factors may inhibit manufacturers from investing in the development of all-boron fly rods, or may result in high rod prices which only few anglers can afford.

Hopefully, the rod companies will be equal to these formidable challenges and will develop and produce advanced boron fly rods at affordable prices. I personally plan to participate in the innovative activities required to bring this to fruition. The payoff is not just newer and different fly rods, but fly rods that will cast further and with greater accuracy, and that will withstand a lifetime of fishing wear and tear. Today's boron offerings demonstrate the promise of this space age material.

(Don Phillips produces rods ranging from a six-foot for a two-weight line to a nine-foot for a five-weight line. He offers a unique warranty; if a rod section breaks within one year from delivery, for any reason, it will be replaced (one time only) free of charge. Write to him at; FlyCraft Associates Inc., 52 Suffield Meadow Drive, Suffield, Connecticut 06078, U.S.A.)

(From Piscator No 109, July 1982)