I bought some foam shale cliff variations that I will need to make molds of. I have 4 total but one was on back order and is quite large. The two smaller ones pictured are a firm /stiff foam while the larger one is a soft flexible foam, I have no idea what type of foam the one on backorder is made from. I have never made any type of mold in my life but this is the only way I can afford to to do my layout as these pieces and the one on back order set me back $100.00 alone. I am planning on just finding or fashioning a tray with sufficent depth and size laying the foam rock structure in the bottom face up and applying several thin coats of latex, reinforcing a few layers with gauze. My question is wether or not I should prepare the surface of the foam rock in some way to help with releasing the mold? The surfaces are pretty detailed in some parts with nifty undercuts and such. What recommendations might you make before I ruin something or waste alot of material? Thank you for your advice... I'd be lost without it.