Artificial stone has a number of uses in landscaping and craft projects. You can create stones for a pond or fountain, or even a hollow rock to hide something. Creating a stone from white cement or portland cement creates a sturdy construction that, if sealed, is weather resistant and adds the look of real stone to your landscaping.
Shape your foam block to roughly the size and shape you want the rock to take by cutting away pieces with the razor knife. You don't have to create a finished shape here; this is the base, so think core, not outer dimensions.
Wrap the foam base in the wire mesh and shape it into the rock shape you want. Wear the leather gloves for this process to avoid scraping or cutting your hands. Fold the edges under along the bottom if you are creating a flat or hollow rock, leaving the centre area of the bottom open, and hollow out the foam in the centre after the wire mesh is shaped.
Mix portland cement, the sand and vermiculite or perlite pellets in the bucket. The portland cement should be a 2:1 ratio with the other two components. Add water according to the instructions and mix. The consistency should be like thick mud.
Apply the portland cement mix to the base in a thin layer with the trowel, shaping and smoothing it as you go. Continue adding the mix until you have the rock in the shape you desire. You can "carve" the stone with the sharp edge of the trowel to create a varied surface if you wish.
Allow the rock to cure according to the time on the cement package instructions.
Mix another batch of cement, this time just the portland cement and water. Apply a thin coat to the rock, and allow to cure. When completely cured, at least two to three weeks if possible, you can weatherproof your rock with a sealant.