EPOXY BONDED SAND - EPOXY BONDED STONE
How to make imitation sandstone, permanent sand
sculptures and sand carvings.
can easily make cast products that have the look of
something carved from sandstone. Or you can make a
permanent "sand castle" type sculpture.
You need a rubber mold to form the cast product. If the
product is fairly shallow, such as a plaque, you can use
a thick-walled silicone rubber or polyurethane rubber
mold. If the product is deep or if the mold is a thin
latex rubber mold, you will probably need to make a
rigid backup mold around the rubber mold. You will be
pressing the epoxy sand mixture into your mold, and an
unsupported rubber mold will distort out of shape.
made with this technique will reproduce the mold very
well - you can use a mold that has fine details and your
cast product should come out nicely.
You should use a release agent on your rubber mold to
prevent the epoxy from sticking, and to prolong the
mold's life. You can use special spray-on release agents
supplied by your epoxy supplier, or you can wipe a thin
coat of petroleum jelly onto your mold.
You need ordinary builders sand or "play sand", such as
is used for making concrete and mortar. If you want your
cast product to have a very even-grained look, you
should run the sand through a sieve and remove all the
You need clear epoxy. If you are testing the technique
or making small products, you can use the type of clear
epoxy sold in small bottles in hardware stores and craft
stores as an adhesive. If you will be making many
products, it will be less expensive to buy clear epoxy
casting resin from a plastic resin supplier.
You need mixing sticks and containers. With epoxy, you
can use wood sticks, waxed paper cups, and many types of
throwaway plastic tubs from food products.
If your mold is deep, you will need a stick for tamping
and packing the sand mix into the mold. You can use a
wooden dowel or other stick. For shallow molds, you can
use your fingers (protected by rubber gloves).
Remember to wear protective gloves and eyewear when
working with epoxy, and work outside or in a
Epoxy does not cure at low temperatures. It is best if
you can work in an area at about 70-80º F.
your kitchen, get some fresh, moist brown sugar and play
around with it a bit. Stir it, pack it in a measuring
cup, and press it with your fingers. The way the brown
sugar looks and acts is almost exactly the way the epoxy
bonded sand will look and act as you pack it in your
mold. Notice that the brown sugar has no visible water,
but it is moist, sticks to itself, and can be packed
tightly in a cup.
Prepare your mold with release agent if necessary. Put
enough dry sand to fill your mold in a mixing container.
Put on gloves and safety glasses.
Mix a very small amount of epoxy compared to the amount
of sand you need to fill your mold. For each cup of
sand, you will need less than one fluid ounce of epoxy.
Add part of the mixed epoxy to the sand. Stir the sand
and epoxy very thoroughly with a mixing stick. The
grains of sand will quickly start to moisten and clump
together. Mentally compare the mixture to the brown
sugar you played with earlier. If the sand seems dry,
crumbly, and doesn't stick to itself very well, add more
epoxy. If the sand seems wet or there is any visible
liquid, add more sand. When you get the mix just right,
make note of how much epoxy you used, so you can
duplicate your results the next time you make this
When the sand mix seems just like brown sugar, add about
a 1 inch layer of it to your mold. Use a wooden dowel or
other stick, and tamp the sand down. Add another layer
of sand, and tamp it down on top of the first layer.
Continue until the mold is full. To make a smooth
surface on the final layer of sand, you can press and
smooth the sand with a piece of waxed paper.
Let the casting cure until hard, and remove it from the
SOLUTIONS FOR PROBLEMS
Cast product has a smooth or glassy surface
where it contacted the mold, instead of a grainy, sandy
Use less epoxy in the casting mix. You should not see
any liquid epoxy in the mix - it should be just moist.
Finished casting crumbly, not strong.
Use more epoxy in the casting mix.
Casting never cures, or cures like taffy (not
Can be the result of low temperatures. Try to work in an
area of at least 70-80º F.
Can be the result of old resin. Use fresh resin.
Can be the result of damp sand. Make sure the sand is
dry. You can put it in an oven for 15 minutes or so at
the lowest setting if there is any doubt.
Cast product does not reproduce all the detail
of the mold.
Tamp the mix into the mold with more force. Pay special
attention to undercut areas.
Sieve the sand before use, so all the grains are the
OTHER THINGS TO TRY
can use the same general technique with small pea
gravel, crushed glass, or even sawdust. Just be aware
that the larger the size of the filler material, the
less it will be able to reproduce the details in your
use sawdust, remove all the very fine dust with a sieve,
and use only the larger shavings and chips. The sawdust
will absorb resin, so you need to use more resin for the
same size casting than you would if using sand. The
finished product will look similar to something carved
or pressed from particle board.
can use colored sand to make your products, or add
colored sand to certain areas as an accent, or alternate
layers of different-colored sand. Experiment!
can use polyester resin instead of epoxy resin, but you
need to work in a very well-ventilated area. Your cast
products may not be as strong as epoxy either.
a PDF source list
Includes 26 suppliers of all mold making and
casting materials mentioned in ALL the demonstrations on
this web site, including silicone rubber, polyurethane
rubber, latex rubber, polyurethane plastic, epoxy resin,
polyester resin, molding clay, foam board, release
agents, pottery plaster, Hydrocal, metal powders, other
plastic resin fillers, and gelatin molding compound.
With company names, addresses, phone numbers, and web
sites. Downloads to your computer as a PDF file.