Make Fake Outdoor Rocks & Caves
Fake rocks and fake rock caves are used for a variety of outdoor purposes, such as disguising unsightly pipes and similar items, as decoration around pools and fish ponds and as rock gardens. There are a few ways of creating fake rocks and caves, such as sculpting them out of roof sealant or creating a cement mixture for decorating fake rock molds. There are also several companies that specialize in fake rock and cave design should your piece need some extra work. Does this Spark an idea?
Instructions
Rocks
1. Study real rocks and boulders, such as their pitting and crevices in order to match your fake rock as closely as possible. Create a mold for your rock with chicken wire and stuff the form with newspaper to keep it from collapsing.
2. Make a coating for the fake rock by mixing one part portland cement with one part builders sand, two parts peat moss, an acrylic fortifying additive and enough water to make a consistency similar to a "mud pie." You can also add concrete dye colorants to the mixture if desired.
3. Apply the mixture using a large, porous sea sponge to create texture and a point trowel for making rock veins. The mixture should be at least 3 inches thick over the mold. Place the wet rock in a large plastic trash bag and seal it as tightly as you can so as to cure it. Inflating the bag somewhat will prevent the bag from touching the rock.
4. Set the bag in the sun and occasionally open the bag to mist the contents with water before re-sealing. Misting the rock periodically is important as you want the rock to retain moisture, thus drying slowly and preventing the applied mixture from cracking and crumbling. The heat from the sun, combined with the misting, creates a very moist environment, which the mixture needs to cure properly. The curing stage takes anywhere from two to four days.
5. Take the fake rock out of the bag once it is cured completely (that is, completely hardened) and rub the rock's surface with a real rock if desired to create additional texture. Apply a stain or painted finish to further add to a more realistic appearance. Allow to dry and follow with a concrete sealant to protect the fake rock's texture and color.
Caves
6. Follow the above procedure for making fake rock to create a fake rock cave. Make larger boulders using the chicken wire. Use several molds or one giant mold depending on preference and access to materials.
7. Use heavy-duty industrial glue to keep the rocks together. Foam roof sealant can also be used to fill in any gaps between the rocks. Mold roof sealant as desired before it dries and paint it to match the colors of your fake rocks.
8. Display your fake rock cave as needed. Use it as a playhouse for small children or as a decorative unit for pools and fish ponds. Also try calling companies like Cave Rock Design and Authentic Rocks for professional installation of rock caves.
