Fillet

This next step is one that a lot of builders skip but one that I think is very important. The strength of carbon fiber is primarily in tension (pulling from each end) and to optimize the properties of carbon it is best to avoid crimping (bending the fiber) and maintain the continuity of the fiber. Because the joint in a bicycle frame forces the fiber to be crimped I add a fillet under the laminate which allows the fiber to follow a smooth radius allowing me to minimize or eliminate crimp. This process requires that I build up an epoxy fillet, allow the material to cure and then go back in and finish it the same way I would a brass fillet on a steel frame. It adds a lot of work but the performance and the appearance of the final product make it worthwhile.