Manufacture of a Composite Developments Fishing rod blank;
The manufacture of a fishing rod blank can be broken down into three parts; design, rolling, and finishing.
Design;
Materials; At Composite Developments we have ten different types and grades of fabric. Carbon fibre is predominantly the main fibre used due to its high stiffness to weight ratio and it’s sensitivity. Where a higher degree of bend is required and weight is not a crucial factor we use glass. Glass fibre is very good for impact strength and will bend through a much tighter arc than carbon before failure. There are three different moduli of carbon fibre used at Composite Developments. Standard modulus (33msi), intermediate modulus (43msi) and high modulus (55msi). The higher the modulus the stiffer the fibre. This stiffness however comes at the expense of strength. High modulus fibre is about 60% stiffer than standard modulus fibre but will only stretch about a half the distance before failing. It is therefore a very poor fibre to use towards a tip section where a high degree of bending is required. Although ultra high modulus fibres are available, up to 85msi for PAN based carbon and 100msi for Pitch based carbon, these fibres are extremely fragile and offer little advantage in fishing rods. It should be mentioned that as the modulus of the fibre increase so does the price. Currently intermediate modulus is about twice the price of standard modulus and high modulus twice the price of intermediate modulus carbon, while standard modulus is about twice the price of glass fibre.
All materials used are in a form called ‘prepreg.’ This is where the fibre is pre-impregnated with resin (around 30-33% resin by weight). The advantage of prepreg is that very low percentages of resin can be achieved in the end product producing higher mechanical properties. It is also much cleaner and easier to work with.
Structural design;
Hoop strength – Carbon Helical; The unique feature of Composite Developments rods is the carbon helical used to produce our 100% carbon rods. This carbon helical is wound on at the beginning of the process. The carbon helical gives the rod blank extremely good strength to help maintain it’s circular shape in bending (hoop strength). With out this helical the blank would kink and break like a drinking straw. Most other manufactures use a glass scrim to create hoop strength. Although much cheaper than a carbon helical, glass scrim is heavier, weaker and less sensitive. Flag layout and rolling; Once the types of fabric to be used in a blank are decided and the dimensions are calculated the fabric called prepreg is rolled out and cut into shapes called flags. These flags are then placed on the rolling table and a mandrel (tapered steel shaft) with the carbon helical wound on is place at the leading edge of the flag. The mandrel is then over the flag causing the flag to wrap around the mandrel as it rolls, forming the blank. Cellowrapping and baking; Once the flag or flags have been wrapped around the mandrel they are put through a cellowrapping machine which wraps a plastic heat resistant tape around the blank. This process squeezes out any remaining air in the blank and will keep it intact during the baking process. Once cellowrapped the blanks are baked at 150 degrees Celsius for around one hour. After baking the blanks are then removed from the oven and placed in a mandrel extractor which pushes the blank off the steel mandrel leaving a hollow shaft.
Finishing;
The first step is to remove the cellowrap with a knife. The blank is then passed through a centerless wet-belt grinder to remove the resin scale left from the baking process. Blanks are then strength tested and checked for straightness before going through a number of hand grinding and sanding processes to prepare for painting and fitting together of multi piece rods. Painting Composite Developments uses two different painting processes depending on the type of blank to be painted. Pouring; This process is used with larger blanks. The paint is poured down the shaft and then the shaft is hung to dry. This process yields an extremely high quality paint job with excellent paint thickness and durability. Squeegee; Smaller blanks are painted using a squeegee process where the shaft is pulled through a paint pot and then through a latex hole which removes excess paint off the blank. This process yields a very thin coat of paint that adds very little to the weight of the blank.
