Advanced Materials CARBON FIBER - STEEL These products are produced from seamless aluminum coating and covered with carbon fiber in an epoxy matrix. An external layer of glass fibers in an epoxy matrix is applied over the tube. This external glass fiber layer is applied to increase the tube's resistance to impacts and abrasions that occur in use. Following high temperature hardening of the epoxy matrix, an external gel coat is applied to the surface of the tube, ensuring that the surface of the cylinder is smooth and easily cleanable.