My previous hydrofoil molds were made of expanded PVC, and that required filling in the pores with glazing putty and then painting with epoxy before they could be ready to use.
I just got some HDPE, so once the molds are carved, all I will need to do is sand it really smooth. I may not even need a mold release.
This one is going to be a bidirectional hydrofoil, which means I won;t have to turn around in order to change direction. The foil shape has to be symmetrical, so water can flow over it in both directions, and still produce lift. It probably won;t be anywhere near as efficient as a regular hydrofoil, but it should be a lot of fun to ride.
I am cutting both sides of each piece of HDPE so the mold is of uniform thickness. I want to bend the mold so I can get some anhedral into the final product, and HDPE is far stiffer than PVC.
![20180715_192055[1]](http://discuss-assets.s3.amazonaws.com/original/3X/f/6/f69de590b627d100aaea8615687b05cb74befa77.jpg)