How to Build Fake Rock with Cement

Two Methods:Making a Simple Fake RockUsing a Mold

Instead of buying or collecting real rocks, you can make your own with cement. Here are two methods for mixing and building artificial rocks for landscaping and design.

Method 1
Making a Simple Fake Rock

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    Buy a bag of ready-to-mix cement and a bucket.
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    Mix the contents of the bag in the bucket with water.
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    Smooth it until it's almost round, but still looking like a rock.
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    Wash your hands immediately and let the cement dry overnight.

Method 2
Using a Mold

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    Follow the above method and add the steps below to build more realistic-looking artificial rocks.
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    Use specialized tools, materials and skill (achieved through practice).
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    Build a form. Use rocks you have in your yard. Clean the rock first, then place it where you can work with it. Using contractors foam sealant, coat the rock with a heavy layer. Let dry and gently pry the foam mold off the rock. You can also use the same method but place the rock in a box. Place the rock inside the box, spray interior with foam sealant and allow it to dry, then tear the box away from the foam. Don't go crazy on the foam.
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    Mix your cement and pour it into the mold. However, to keep it from sticking, you may want to use cooking spray before pouring the cement. Another good method is to rub the rock with Vaseline.
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    Mix the concrete per directions so it is thick but pourable. You can add color to the concrete at this point by mixing colors that can be purchased at Home Depot or Lowes. You can also use the red dirt from your yard to mix into the cement for color; it works, but you have to watch that you don't add too much - just enough to give it some color.
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    Sculpt the concrete. If you use a mold, you may not be able to sculpt the "rock." However, if you take the rock out of the mold before it's completely dry, you can still scrape it to sculpt the shape a little.
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    Texture the concrete . Before pouring cement into the mold, you can add leaves, small flat rocks and other paraphernalia from around your yard to give the "rock" character. Pouring flat rocks or flagstone type rocks can also be accomplished and put in crushed glass or other interesting items before the pour. Then when you turn it out, the pretty stuff will be on top.
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  • You can also dig holes in the ground for your moulds if you have the space.
  • Consult your local hardware supply store to determine tools and materials needed. Explain your project (basic vs. advanced) and ask questions.
  • If you plan on keeping these rocks for a long time, get some spray sealer or varnish, and give it a couple of coats.
  • To make very natural looking rocks first make a rock using roof sealant ( then use plaster to make a mold. then when that sets use cement to fill that mold this makes a durable yet realistic fake rock

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Categories: Landscaping and Outdoor Building