1 Answer

Instructions
Form the Foam

1
Cut pieces of foam to the desired shape and size of your rock; lay them on top of one another, if necessary, to achieve your preferred shape.

2
Cut a length of wire long enough to pierce through the layers of foam. Bend a 90-degree hook on one end.

3
Push the wire through the stacked foam pieces until they are secured together; the hook will secure the wire to the foam.

4
Use additional pieces of foam to build up the sides of the fake rock, creating slopes. Attach them with the wire, using the same technique as before.

5
Use a razor to cut large chunks into the foam, if desired, to create custom rock designs.

Complete the Rock Form

6
Secure small, thin pieces of foam to various locations on the form with wire; these spacers create a thin gap between the foam and the steel mesh you will next apply.

7
Cover the foam with a layer of steel mesh and secure the steel mesh to the foam with wire pieces featuring a 90-degree hook on one end. Simply push the wire through the mesh until the hook secures it to the boulder.

8
Push any open mesh ends into the foam. Ensure that the mesh is completely secured to the foam.

9
Wrap chicken wire around the formation a few times, making it nice and tight. Use pliers to bend and shape it as needed.

10
Attach the chicken wire to itself by twisting the ends together with pliers, wrapping them closed.

Apply the Grout

11
Purchase polymer-modified grout in a variety of shades ranging from a light, grey shade to a dark rock color. Either purchase or mix at least three different colors. Choose colors that mimic those found in natural rocks.

12
Use a trowel to apply the lightest color of grout over the left half and top of the rock. Ensure that the grout completely covers the wire, moving beneath the wire frame to the foam underneath and into the area left by the foam spacers.

13
Allow the grout to dry before applying it to the right half and bottom. Follow the grout instructions to determine the drying time. It may take anywhere from thirty minutes to twenty-four hours for the grout to fully dry.

14
Continue to apply layers of grout in the same manner, working from the left-top to the right-bottom and transitioning from the lightest to the darkest color, until your rock is the color and shape you desire. Allow the grout to dry between applications. Again, follow the grout instructions to determine the drying time, which may range from thirty minutes to twenty-four hours.

15
Wait a few days to allow the layers of grout to solidify and then apply one last, thin layer; use the darkest color.

16
Use a wire brush to scrape away at the grout layers, creating a natural rock look. Use waterproof paint applied with a sponge to add custom colors, if desired.

Cure and Neutralize the Formation

17
Allow the piece to completely dry.

18
Submerge the fake rock in water or mist it several times a day for a two to three weeks to completely cure the grout.

19
Neutralize the fake rock after the grout has cured for several weeks by placing it in water and leaving it there for four weeks. Change the water once a week. It's necessary to neutralize the stone because when it is freshly cured, its pH and rH levels are raised to levels unhealthy for plants and animals.

20
Seal the fake rock in epoxy to prevent the growth of algae and moss.

Read more: How to Make Your Own Fake Rocks for a Waterfall | eHow.com http://www.ehow.com/how_8112274_make-own-fake-rocks-waterfall.html#ixzz2BMGUwqEq