Casting Materials & Its Classification There are many different types of casting materials available to suit various types of projects. If you are creative with jewelry then you may wish to look at the various resins for casting unique resin jewelry pieces. If you are after a fun and creative party activity for children then you may want to investigate the casting of plaster ornaments and plaques for them to paint. Plaster is the most ideal casting material for this purpose. Every project has its own requirements and here we will look at the most popular casting materials and their uses. GYPSUM PLASTERS Gypsum plaster is a versatile, cheap and safe casting material to use for many different types of applications. This material only requires a latex mold and not the more expensive silicon rubber molding materials which are generally needed for resin or pewter castings. Casting plaster types are best suited for general purpose plaster casting such as for children's plaster painting ornaments. Casting plasters have a harder surface which prevents chipping and provides a good surface for painting. For projects that require a harder and more durable plaster casting material you might want to look at one of the stone plasters. These are more expensive but the strength is superior. RESINS There are many types of resin. They are generally made up of polyester, epoxy or polyurethane and can come in either clear or opaque finishes. We will look at the various types of clear and opaque resins and their applications. Opaque Resin: The most common type of opaque resin in use today is polyurethane two part resin. This comes in many forms and various setting times. The time it takes to set hard when mixed in most cases is very short, usually 3 - 5 minutes. This resin gets really hot and it is recommended to use a Silicone Rubber Molding Material. These types of resins are not as brittle as clear polyester resin and are therefore suitable for making model parts and small detailed items. The castings can be painted, drilled and sanded. Transparent resins: The cheapest clear casting material is polyester resin. This requires the addition of a toxic chemical called MEKP to create the chemical reaction which hardens the resin. Special care needs to be taken when using this material and gloves should be worn.
Polyester clear casting resins produce a very clear and hard casting which can be polished by hand to produce glass like effects. This product is excellent for embedding and due to the slow setting times it allows most bubbles time to rise to the surface. Another type of transparent resin which is really starting to become popular is the epoxy type. These resins are much easier to mix at a ratio of usually 1 to 1 and have low odour. They are also a lot less toxic than polyester resins. Environ Molds has been manufacturing and distributing superior quality art supplies throughout the world. http://www.artmolds.com