If you want to decorate your home, garden or patio with concrete sculptures or reliefs, you can choose from a variety of premade items at your local garden store. If you want your decor to be one-of-a-kind, though, you can create molds to make your own concrete sculptures. Creating a concrete mold is not an easy process, but it can help you create decor that is uniquely your own.
Things You'll Need
Clay sculpture or found item
Pourable mold rubber
Create your sculpture out of modeling clay, unless you plan to cast a found object. Relief sculptures, which are flat on one side, are much easier to cast than full-dimensional sculptures. If you choose a full-dimensional sculpture, use a section of thin wire tied to two dowel rods to cut it in half lengthwise. You will create two molds, one for each half.
Coat the finished sculpture or found object with petroleum jelly. This will keep the object from sticking to the mold. Spread the petroleum jelly as thinly as possible so it does not alter the texture of your mold.
Fill a leak-proof container with about 1 inch of pourable mold rubber. Place the sculpture in the container. Fill it with pourable mold rubber until it reaches the flat back of the sculpture or the center cut, if you are casting a full dimensional sculpture. Let it sit overnight to allow the rubber to cure.
Pull the mold off of the clay sculpture or found object. Begin at one corner, gently bending the mold away from the cast object. Continue this process with the other corners of the mold, alternating corners until you have freed the mold.
Coat the mold with two thin layers of liquid latex before pouring concrete to cast your decorations. This will keep the concrete from adhering to the mold.
If you are casting a full-dimensional sculpture, insert a short dowel rod into the top of one of the halves of the clay sculpture. When you cast the concrete, you will put the two mold halves together. The dowel rod will create a hole you can use to pour in the concrete.
Always work in a well-ventilated area. Pourable mold rubber and liquid latex give off fumes that can irritate your eyes, nose and throat.