Another challenge was put forward – to make a leather cup washer to replace a worn one from a bicycle track pump. These cup washers were often used in pump applications, both air and water, although I’d never really thought much about how they were made.

After a bit of research the method of construction was to press the leather into a form to shape the leather. Typically, in making leather items, the leather would be soaked in water before being pressed into a form. Once dried, the leather would retain the shape of the form.

However the general advice was to soak the leather in hot paraffin wax rather than water. I was quite intrigued by the process so the challenge was accepted!

The project dimensions were: