One of the most common questions asked by the consumer is ‘how much carbon?’ with the perception that more is better. That is far from the truth, so to shed a little light.
Firstly the quality of carbon (manufacturing point) is important. Toray (Japanese) Carbon is often considered the best, but Carbon from Germany, Scotland and South Africa (to name a few) are all high-quality. Sticks are usually made in Pakistan and most major brands will import Carbon into Pakistan to make sticks. Local made carbon is not usually as good. But it is difficult to know if a brand uses imported carbon.
The number of filaments in the carbon fibre is relevant, 1K, 3K etc relate to the number of filaments of pure carbon within a fibre or ‘tow’. 1K is used in aeronautical industry and electronics. 3K and 6K are commonly used in sport as they have the right combination of weight and strength. Anything over 6K is very dense and too heavy for sports equipment. Again this isn’t a common line of questioning from the consumer but may come up.
Carbon fibres are a straight line material and so provide stiffness in a single direction. To provide stiffness in multiple directions the fibre can be woven into a multi-directional sheet (seen as an obvious weave in the sticks surface) or single direction sheets can be layered over each other to create the multi-directional stiffness.
40% of the weight of a composite stick comes from the resin within it. So a stick can’t be 100% carbon. However it can be claimed that 100% of the composite materials in a stick are carbon. Mercian do not believe this gives optimal strength and so always combine the carbon overlay with a composite micro-skeleton made from fibreglass, Kevlar (aramid) and basalt.
Carbon is stiff but brittle. The stiffness means that the energy created by the player when striking the ball – hit / slap – transfers to the ball and is not absorbed by the stick. Maximum energy transfer allowed by the FIH is 98%. But this stiffness means that the stick will not absorb energy on trapping / receiving so needs soft hands!
The brittleness of carbon means that if the fibres are broken (stick tackle / post impact) they will crack and the stick can or will fail. This is not a manufacturing fault.
Other materials can be used in conjunction with carbon to get a positive performance outcome. Special chemicals are used with paints and lacquers to get them to bend to the top layer of carbon and create high-quality graphics.