I'm looking at expanding my existing pond from 700 gallon pond to a
3000 gallon one. I'd like build a pond wall that is at least 1 ft high
to prevent my small dogs from jumping in and to avoid problems with
water run-off.

Among some of the inexpensive solutions I've been looking at... is
building hypertufa blocks (combination of portland cement, sand and
peat) to use for the walls. Then within the walls, I plan to put a
large 45 mil EDPM liner (a liner similar to what I'm using on my
current pond).

Has anyone built hypertufa forms? If so, what did you use as a mold to
build your forms? Can a simple plastic box be used as a mold? Or it it
difficult to get the form out once it hardens?

Thanks!

Robin