Concrete fountains are popular additions to gardens, decks and patios. These fountains are produced by pouring specially prepared concrete into a series of moulds, which are typically made from latex rubber, silicone or acrylonitrile butadiene styrene (ABS). With some patience and the right materials, you can turn out your own fountains by making moulds of fountains you particularly admire. Because the moulds are reusable, you can make many fountains from a single mould.
Disassemble the fountain if it is built from multiple pieces. You'll need to make a mould for each piece.
Clean and dry the fountain thoroughly.
Mix equal quantities of the resin and catalyst of the mould-making polymer in a clean plastic container. Mix enough to cover the entire surface you want to reproduce.
Place the fountain face up on a level surface, if it's a one-sided design. If the fountain is sculpted on all sides, place it bottom-down in a level area where you can conveniently reach all sides.
Brush or trowel a 1/4 inch thick layer of the mould-making polymer over the sculpted side (or sides) of the fountain. Be sure to wear rubber gloves for this.
Allow the polymer to cure for at least one hour.
If the fountain is sculpted on all sides, carefully make a cut through the cured mould running down the centre of the mould on opposing sides of the fountain. This will allow you to remove the mould without tearing it.
Carefully peel the cured mould from the front or sides of the fountain.
Mix equal quantities of both parts of the mould-shell compound in a clean plastic container.
Brush or trowel a thick layer the shell compound onto the back of the mould.
Allow the shell to harden for at least 24 hours before using the mould.
Fountains are usually heavier than most other concrete moulding projects. For this reason, use of a hardening shell is recommended, so that the weight of the concrete does not distort the mould during the casting process. If you've made a two-part mould, you'll need to reconnect the two halves with tape or wire before pouring the concrete into it. Be sure to make a note of where water pipes and other fixtures are placed in the fountain you're duplicating. You'll need to add these parts to the uncured concrete during the casting process. If you're copying a very large fountain, you may want to consider pressing fibreglass cloth into the wet shell compound and then covering it with another coat. This will make the mould much sturdier.
The compounds used in the mould-making process cause skin irritation. Always wear rubber gloves when dealing with these products. If you're making a mould from a heavy fountain, get help in moving or disassembling it. The concrete in fountains is usually not reinforced and will break easily if dropped. Check the setting time of both the moulding and shell compounds before you start mixing. Mix no more than you're sure you can apply before the compound sets up.