I am looking into casting a few small concrete blocks to build some steps which I will reconfigure over time.
I've found a styrofoam box which gives me the shape I'm looking for, and I'd like to find a way to build a form which I can reuse in order to produce as many blocks as I would need.
Since styrofoam can be broken easily and all the examples I studied for casting concrete with styrofoam forms involve breaking the forms after casting only 1 object, I started thinking about using acrylic sheets to build a small box inside the stryrofoam, with the hope that I can slide out that acrylic form after casting, take it apart to retrieve the block, then put it together again inside the box.
I have 3 questions:
Is acrylic a good material to use for concrete casting?
What can I do to minimise the chances of the acrylic sheets sticking too much to the concrete object such that I might risk snapping them?
Might there be a better way to improve reusability of a styrofoam form?