Cast off

Wayne Carkeeks' leading link fork design requires the use of 60 shore hardness elastomer donuts to support two short swingarms holding the front axle. These can be had from Mackay Rubber at about NZ$75 a unit which works out to NZ$150 per fork. I found a source for the 2 part casting urethane with a similar hardness. At around $100 for 1.5kg of urethane I can cast about 10 sets. Leaving me needing some time on the machinery to make some molds.



The first molds were solid blocks of aluminium(square mold on the right) milled out to the dimensions with caps and relief holes for overcast. The elastomers proved just hard enough to demold that this was not suitable though the first set came out very nice. For the next molds I went three part and made 4 in total so I can cast a set at a time. I used blue acrylic tint for the first set as used for colouring epoxy which worked well. Though the second set I used a grey tint provided by the supplier. These did not cure nicely and will need to be redone. I'll stick with acrylic tints I know too.