Gypsum can be fashioned into different types of plaster. While plaster of Paris is a popular material, artists prefer to use specially-treated fine art casting stone powders for making plaster casts.
Mold making and casting opens the doors to a variety of materials that can be used for making molds and casts. There are simple materials like clay, plaster, wax and alginate to rubbers and resins. Some of these materials open up a further choice – like rubbers can be of the silicone, latex, polyurethane or thermoset types whereas resins can be polyester, epoxy or polyurethane. Similarly, even when it comes to gypsum, the artist can choose between plaster and stone.
Let us take a look at the categories of gypsum that can be used for plaster casting:
Plaster – Plaster is raw gypsum that has been treated by crushing and treating to form plaster powder. The most common variant is plaster of Paris that is available as a fine powder which is economical, easily accessible and quite user-friendly too. It finds various uses in building works like finishing walls, false ceilings, decorative materials and even for setting broken bones. All it requires is mixing the plaster powder with water to form a paste before using it.
However, the usability in mold making and casting is actually quite limited as plaster of Paris is naturally soft and chalky. It starts chipping and cracking over time and fails to hold details well.
Stone –This is also a gypsum-based plaster of Paris, but it is specially heat-treated to make it more amenable for fine art casting. It is formulated as a dense formula that will create very hard casts that will capture fine details, are durable and can hold the finish, unlike the generic plaster of Paris. Moreover, it is easy to work with too. At times, fiberglass fiber is added to this mold powder for additional strength.
Apart from regular casts, it lends itself well for making latex slurry molds too.
The best choice
Castrite Art Casting Stone is a popular material of choice for making art castings of all types. It gives a natural bright white finish and can be cast in alginate, resins, silicone molds and even plaster bandages.
That’s not all. The same plaster can also be fashioned into plaster bandages which is nothing but gauze rolls infused with plaster. The bandages are wetted and applied to form basic form molds or to reinforce flexible molds with an additional shell mold.
In sum, plaster is made from calcium sulfate that is derived from the naturally-occurring gypsum. It takes two forms that have diverse uses. The plaster stone variety is best used for molds, casts and life casts.
EnvironMolds is a popular art supplier that offers a range of mold making, casting and life casting materials of top quality at reasonable prices. There are a range of plaster materials for plaster casting and plaster bandages as well apart from the necessary supplies and tools.