from The Wise Fisherman's Encyclopedia
Solid Rods. Solid steel rods probably had their origin when some enterprising mechanic installed a handle and a set of guides to an ordinary fencing foil. The latter, while extremely flexible, is almost totally lacking in casting ability. Weight-wise, a solid rod is the least efficient material distribution possible. The extreme (outer) fibers are in closest proximity to the non-working center, or neutral axis.
Tubular Rods. On the other hand, the most efficient system is embodied in a thin-walled
tube. This was recognized at an early date. No feasible method existed at that time
whereby either a continuous or a step taper could be incorporated into such a tube to give it the proper rod action. A leading implement manufacturer, however, devised a system of
repeated drawing operations whereby a portion of the rod section was drawn through a
sequence of reducing dies, each operation successively reducing both outside diameter
and wall thickness.
It is apparent that dimensionally, this method of manufacture leaves little to be desired. A fair degree of concentricity between inner and outer diameter results in a relatively uniform wall thickness throughout as evidenced by only the slightest traces of knock. The best examples of the art are represented in the heavier rods designed for bass bug fish- ing, as well as in the fast tapered, short rods used for plug casting. Light-and medium-weight rods in the 7- to 8-foot category are far too stiff to be acceptable by experienced trout fishermen. In this case the high strength of cold drawn alloy steel appears to defeat its own purpose. For proper action, a fine trout rod tip requires a wall thickness of only a few thousandths of an inch. Practical considerations limit wall thicknesses from .004" to .007". As far as is known these shafts have never been offered to the amateur rod maker.
Disadvantages. Not unlike the other rod-making materials, steel is not without its shortcomings. Rumors have been circulated to the effect that the thin steel structure becomes brittle in cold weather. While it is known that low temperatures do have an embrittling effect on some steel alloys, it is doubtful that fishable water could exist as a liquid under those circumstances. In fact, the author has never seen a failure definitely traceable to this cause. The two main causes of failure are (1) wall collapse and (2) rust. Since these rods are hollow throughout their length, they are subject to collapse due to buckling on the compression side of the wall. A reinforcing effect is realized at each step or shoulder. At this point the wall is sharply tapered in cone fashion as it blends into the adjacent straight cylindrical portion. Proof of the effectiveness of these tapers is manifest in the nature of the breaks. When a failure occurs near a step, or shoulder, it usually breaks clean. If the break takes place elsewhere it is nearly always characterized by the "pinched' appearance typical of a primary wall failure. Appraised from this standpoint alone, the step construction is probably more sound than a straight unbroken taper. Rust is probably responsible for more steel rod failures than all other causes combined. Strangely enough, the rusting most frequently takes place inside the tube. Elaborate measures must be taken to hermetically seal a thoroughly dry interior. Water vapor admixed in the air inside the rod will, on the first exposure to cool temperatures, condense on the inner surface and begin the attack at the rod's weakest point. Removal of either ferrule or tip guide will admit more water-laden air unless measures are taken to prevent such an occurrence. Generally the outside is adequately protected by copper plating, enamel, and/or varnish.
This wonder metal is the latest contender for honors as a rod-making material. The wartime need for a long-lived, non-corrosive spring material accelerated enormously the refinement and general working knowledge of beryllium copper. As would be expected, the alloy consists principally of copper from which it derives its color, approximately 8% beryllium, and a small amount of nickel or cobalt. This material responds well to heat treatment, attaining an ultimate cold tensile strength of about 200,000 pounds low per square inch. It is relatively heavy, however, the specific gravity being about 13% greater than steel. The basic drawing stock is made from a ribbon continuously cold-formed into tubular shape and welded along the seam in an atomic hydrogen arc. The edges are melted in an incandescent hydrogen atmosphere and then brought together to fuse. No filler rods are used. This tube is then drawn through dies in a manner similar to that employed in the steel step-taper configuration.
Advantages. Chief among the assets of this alloy is an extraordinary fatigue life. It can be continuously stressed to values nearing its yield point without apparent detriment. Being composed principally of copper, resistance to corrosion is excellent. An unvarnished surface oxidizes, becoming reddish brown, the color of an old copper coin.
Disadvantages. The specific weight of beryllium copper is a definite handicap. This property coupled with the relatively heavy wall sections incorporated in rods of this alloy has confined their use to heavy-duty service. In small calibrations these rods, although very flexible, lack the snap desired by most experienced anglers. A number of sharply tapered bait casting and saltwater rods have been examined and their action judged good. Rods intended for spinning and fly casting have been too 'whippy' to compete with steel, fiberglass, or bamboo. It is suspected that a reduction of wall thickness in rods of the latter category will effect a step in the right direction, although there may be reasons best known to the manufacturers themselves why this is not feasible. The writer is not acquainted with those facts.
Bending. Beryllium copper rods may be bent slightly without visible signs of wall collapse. Straightening is accomplished simply by rebending in the opposite direction. Unlike tempered steel, the yield point, i.e., the force or stress required to bend or permanently set the rod without fracture, is about fifty per cent of the breaking point of the material. Thus straightening is a comparatively safe operation compared to the removal of a minor set in the usual types of tubular steel.
Refinishing. A word of warning to those who plan to refinish their own beryllium copper rods: if it is desired to restore the original polish, refrain from using a motor- driven polishing buff. Instead, rub it down by hand, using a good commercial metal polish. The reason for this lies in the fact that this alloy was heat treated at a relatively low temperature. In consequence, the temper may be entirely removed or seriously impaired by the heat of friction generated by the buffing operation.
Rapid strides have been made in the development of improved glues and ad- hesives suitable for rod building. The most successful of the early adhesives was a fish glue called Russian Isinglass. This had to be warmed before using, and in most cases dried very slowly. Attempts were made to add various substances to improve its resistance to water with but mediocre success. Russian Isinglass, in turn, was followed by animal base glues, hide glue, and gelatin base glue. These are water soluble both before and after use. They are prepared by heating in a double boiler, and are applied warm to warmed wood. Sudden chilling is disastrous to good adhesion. Either high humidity, heat, or attack by bacteria, singly or in combination, will cause delamination (separation) of the strips.
Once the equipment for applying these glues is set up and put into operation, the process is quite simple. The glues are held in such high esteem that some of the largest rod manufacturers use them. The reasons given are:
Casein Glue. Casein glue is of ancient origin, but it was not extensively used until 1916—17 when it was widely employed in the construction of wooden aircraft structures for World War I. This is a by-product of skim milk. The curd from sour milk is washed and dried, mixed with sodium hydroxide and hydrated lime, and finally prepared for use by simply adding a proper amount of water. When cured, the glue is water resistant but not waterproof. Repeated wetting and drying will cause ultimate failure, as will conditions favoring mold growth. The glue is easy to use, and sets up quickly enough to remove the wrapping string from a glued-up section in from 4 to 6 hours. Since excessive moisture has been introduced into the wood, longer drying is necessary to remove this moisture as well as to thoroughly season the glue line.
Thermosetting Resin Glues. Of the more recent vintage, a series known as
"Thermosetting Resin Glues" has been developed. Three are worthy of con-
sideration. They are: Phenol-formaldehyde, Urea-formaldehyde, and Resorcsinol-
There are many variations to the above basic glues, but they are of a complex nature and will not be discussed at length. Each type, for instance, can be supplied as a hot bonding adhesive, or as one that sets or cures at ordinary or slightly elevated temperatures. Again, they may be furnished in the form of powder, sheets, or liquid, depending on their intended use.
Phenol-resin. Low temperature types of this glue are of interest to rod makers.
These are marketed as powders or liquids, usually with a separate catalyst, or
hardener. Some powders are mixed with water and applied by brushing. These
usually cure at room temperature (70 degrees F or higher). The two-element glues consist
of a liquid glue and a dry powder hardener. These are ready for use immediately
after mixing. Most of these require curing temperatures of 150 degrees F to 190 degrees F for
approximately 4 hours. A uniform glue line pressure must be maintained during this
The finished joint in both cases is extremely durable; being waterproof, mold, and fungus proof, and resistant to heat up to the charring point of the wood. Although brittle when completely cured, the glue line is so extremely thin that it can follow the deflections incident to any type of fishing without the slightest breakdown. The color is a light tan.
Urea-resin. This glue was introduced shortly after the advent of phenol-resin. It is marketed in similar form to those described above and may be compounded to set at either low or high temperatures. Only the cold setting types should be considered by amateur rod makers. This glue, unlike the phenol. resin, is quite sensitive to the moisture content of wood. It should not be used on very dry material. This is important; failure to recognize this limitation will result in no end of difficulties. A minimum moisture content of 8% by weight is essential to full- strength joints. Only those concerns having access to moisture measuring apparatus should consider this glue. Spreading may be satisfactorily accomplished by brushing. At 75 degrees F, 4 hours is required as a minimum setting period. This depends somewhat on the nature of the material being glued. Bamboo being rather dense would not suffer if allowed to cure somewhat longer. Cold setting urea-resins mature more rapidly at temperatures higher than the 75 degrees F indicated. As an example, an increase of only 10 degrees Fahrenheit (85 degrees F) will effect sufficient curing to permit removal of pressure (wrapping string) in only 2 hours. Increased to 95 degrees F, the setup time is again halved—one hour under pressure being sufficient. Longer heating periods than those indicated are not recommended, as this will impair the strength of the joints. When heating rod sections for straightening purposes, it is important to use as little heat as possible—and for as short a time as necessary. Deterioration at high temperatures is very rapid. Urea-resins, although better than casein under conditions of extended high humidity or alternate wetting and drying, are found somewhat wanting when compared to the phenol and resorcinol formulae. Nevertheless, good joints can be made if the builder recognizes the limitations and assets of this glue.
Resorcinal Resin. Glues of this group are usually of the two-element type, consisting of a liquid
glue and a separate hardener in powder form. A filler, such as walnut shell flour, is ordinarily
mixed with the hardener to facilitate working. In some respects these glues are similar to both the
urea and phenol types. Resorcinol adhesives are quite responsive to temperatures above 75 degrees F,
setting up in approximately one hour at 90 degrees F.
Additional heating does not in any way damage the glued joint, in fact, a rod section intended for conventional freshwater fishing can be glued together, held at 160 degrees F to 190 degrees F for 4 hours, removed from the warming box, scraped, ferrules and cork handles fitted, guides and top mounted, bamboo surfaces sealed, and be ready for fishing the evening of the day the work began! Joints will test in excess of 90% of full rated strength. The remaining 10% will be realized by natural aging, which should take no longer than one week.
The liquids used in preparation of the glue include an appreciable percentage of alcohol. The low water content, therefore, tends to minimize the bamboo swelling so noticeable when other glues containing 40% to 60% water are used. Under conditions of curing with heat the alcohol is rapidly driven out of the joint. From the practical viewpoint this means that the ferrules may be mounted much sooner without fear of loosening due to the shaft's drying and shrinking.
In addition to the foregoing, resorcinol resin is completely waterproof, extremely stable under conditions of heat up to the charring temperature of the wood, and proof against attack by fungus, mold, or bacteria. From the purely functional standpoint there is very little to be desired.
Its color, a reddish-purple, however, is a distinct disadvantage. Regardless of the precision to which the individual splines are cut, it is practically impossible to produce an invisible seam. This is due primarily to the penetrating ability of the glue, particularly when thinned with 5-10% alcohol. Penetration has been measured as deep as .020" which is enormous considering the density of bamboo. Other glues seem to be content to simply lay on the surface until squeezed into the outer capillaries by means of clamping pressure. It is perfectly obvious, then, that it is physically impossible to remove the dark seam lines characteristic of this glue. These are seldom of uniform width, as the depth to which the glue "soaks" is dependent on the density of the wood at that particular point along the seam. The effect is one of incompetent workmanship and a great deal of explanation is sometimes needed to convince the prospective customer otherwise. One of the main features of the old glues lies in their color, which matches closely that of the wood. The seams are there in fact, but are rendered invisible by their hue. Some rod makers have abandoned the use of this glue under just those circumstances to use "the next best."
The perfect fishing rod, if such could exist, would in all probability be made in one piece. Unfortunately this is not practical. Liability to damage in transit, high cost of replacement should breakage occur, and excessive length for easy stowage, are but a few good reasons for the popularity of jointed rods.
It is natural that an unbroken shaft is stronger than one that has been cut in half and then rejoined. Adjustments are sometimes made to strengthen the area of the union. One English rod maker glues small strips of bamboo to those portions of the rod intended to receive the joining sleeve, or ferrule, and at least one American rod maker increases the taper of the rod to produce a slight "swell" at the critical region for the purpose of increasing the strength of the joint.
In the course of the development of fishing rods many designs were created. Some of these were further complicated by the addition of another tapered ex- tension, or dowel, intended to further stabilize the joint. Fortunately, these are no longer in use. When held tightly seated, such devices are very secure. However, the motions of casting soon unseat ferrules of a tapered profile, whereupon the rod falls apart. Screw threads were later added to prevent accidental loosening. The added weight and expense were deemed sufficient reason to search for something better.
The straight cylindrical "sleeve and plug" was devised, adopted, and persists, in one form or another, to this day. The reasons for the success of this design are simple. An accurate round tube is quite easy to manufacture. When properly fitted, the plug can be partially withdrawn from the sleeve with neither the possibility of harm to the rod nor further self-disassembly. Figure 1 illustrates a few forms of ferrules in common use, plus one of the outmoded types, as follows: