How to Make Artificial Coral Stone

Simulating the porous quality needed to preserve living matter such as algae and bacteria that lives on actual reefs can be achieved using basic rock building material. Creating artificial coral is an alternative to buying natural coral. Both require an extended curing time, but the artificial coral can be formed into desired sizes, shapes and colors. From the smallest rock for an aquarium to sculpture, to patio furniture, the building process remains basically the same.

Things You'll Need

  • Large sturdy plastic container
  • 2 plastic buckets, 5 gallons each
  • Rubber gloves
  • Water
  • White porous cement
  • Fine sand
  • Nontoxic and water resistant paint
  • Paint brush
  • Clear aquarium silicone sealant
  • Macaroni
  • Small twigs
  • Crushed oyster shells
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Instructions

  1. The Mold

    • 1

      Dump enough sand into the plastic container to accommodate the desired size of stone.

    • 2

      Mix water with the sand until sand is wet but not muddy.

    • 3

      Scoop, press, hollow out, the desired shape of the stone or stones into the sand. This will be the mold.

    • 4

      Allow sand to dry completely.

    Mixture (Aragocrete)

    • 5

      Put on the rubber gloves and mix just enough water with the cement until the cement can be formed into a ball.

    • 6

      Add small twigs, macaroni, or crushed oyster shells if desired.

    • 7

      Gently press the mixture into the forms in the sand.

    • 8

      Allow the mixture to dry completely. This may take from a few hours to a few days depending on the cement used.

    Completion

    • 9

      Remove the stone or stones from the sand.

    • 10

      Rinse sand from the rock by gently brushing it away and by submerging the rock in clean water.

    • 11

      In another container, submerse rock in clean water. Be sure that the rock is completely under water.

    • 12

      Change water daily for up to 6 months in order to lower the rock's pH factor.

    • 13

      Painting the stone is optional. Use bright colors such as neon orange, iridescent blues, greens and yellows.

    • 14

      Allow to dry.

    • 15

      Apply sealant, especially if the stone will be used in water such as in an aquarium.

    • 16

      Be sure the rock is completely dry before using.