For those who might be interested in building your own molds from HDPE there is a good selection at very good prices at Amazon. Here's what I found:
http://www.amazon.com/s/ref=nb_sb_ss_i_ ... Caps%2C236
If making wooden molds, you could buy the thin sheets and line them with it. Cheaper still.
http://www.amazon.com/s/ref=nb_sb_ss_i_ ... Caps%2C236
If making wooden molds, you could buy the thin sheets and line them with it. Cheaper still.