The Choprical Fish: a Human Powered Party Bike

Step 8 Create a positive form for fiberglass layup

I purchased a 4x8 sheet of 4" household insulation foam for a lumber store and removed the foil sheets from the outside by peeling and then sanding. Note that whenever you sand foam you need a good dust mask. Take your health seriously when doing fiberglass work! If you find yourself coughing or getting headaches, you need to stop working and figure out how to improve your workspace and safety equipment before continuing.

I made a sandwich of three large pieces of this foam. I cut the wheel profile out of the middle layer before gluing up the sandwich with polyurethane glue. The seams were difficult to work with during the sandind and shaping process. I would probably use 30:1 expanding foam next time. Doing so requires building a large box to contain the foam as it expands and hardens. Still, I think this might have been slightly better than using the household insulation foam.

I used a variety of wood shaping and sanding tools to reduce the crude shape to one I began to like more and more. I snapped lots of pictures so that I could compare it to my drawing.