There are many different types of casting material available for many different types of projects. If you are creative with jewelry, you may want to look at the different resins for casting unique pieces of resin. If you are looking for a fun and creative party activity for kids, you might want to explore the casting of plaster ornaments and plates that they can paint. Gypsum is the most ideal casting material for this. Each project has its own requirements and we will look at the most popular casting materials and their applications in this article.
Plaster is a versatile, inexpensive and safe cast material that can be used for many different types of applications. This material requires only a latex mold and not the more expensive silicone rubber mold materials that are generally required for resin or tin castings.
There are different types of plaster and each is most suitable for a specific application. Try to stay away from the types of plaster, because the surface of the plaster does not retain much detail and it has a low surface hardness.
Plaster types of plaster are best suited for general-purpose plaster casting, such as for plaster painting ornaments for children. Gypsum plasters have a harder surface that prevents crumbling and provides a good surface for painting.
For projects that require a harder and more durable plaster material, you may want to view one of the stone plaster. These are more expensive but the strength is superior.
There are many types of resin. They are usually made of polyester, epoxy or polyurethane and can be supplied in a clear or opaque finish. We will look at the different types of clear and opaque resins and their applications.
Opaque resin: The most common type of opaque resin currently in use is two-part polyurethane resin. This comes in many forms and different setup times. The time required to harden when mixed is, in most cases, very short, usually 3-5 minutes. This resin becomes very hot and it is recommended to use a silicone rubber molding casting material.
This type of resin can be colored, but the basic color that can vary from white to creamy beige must be incorporated into every color mix. Special polyurethane pigments can be mixed in part A before they are mixed in part B.
These types of resins are not as brittle as clear polyester resins 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 cast material is polyester resin. This requires the addition of a toxic chemical called MEKP to cause the chemical reaction that hardens the resin. Special care must be taken when handling this material and gloves must be worn.
Polyester clear casting resins produce a very clear and hard mold that can be polished by hand to produce glassy effects. This product is excellent for embedding and due to the slow cure times it causes most bubble time to rise to the surface.
Another type of transparent resin that is starting to become really popular is the epoxy type. These resins are much easier to mix in a ratio of usually 1 to 1 and have a low odor. They are also much less toxic than polyester resins.
Resin jewelry makers have really chosen this type of resin. The only drawback is that larger castings cannot be made. We are talking about castings that are larger than your fist and polyester is still preferred for castings with a larger size.
Tin casting is a popular hobby and people use low-melting metals to make a wide range of model parts, toy soldier badges, and even jewelry. Special molds are needed for this type of casting and there are special silicone rubber mold materials for high temperatures.
There are many types of low-lead and lead-free alloys to choose from and crucibles are good gloves that are recommended.
CONCRETE AND CEMENT
More and more people nowadays use molds to cast concrete objects for their gardens or for their own company. Plastic or polyurethane rubber molds are the most used and are generally more durable.
Special concrete mixes have been developed to achieve a finer surface finish, but even a ready-made bag that is available at any hardware store can be used with good results. The type of aggregate used is also important for obtaining a good surface finish. Remember that once casting has been removed from the mold, it needs at least a good week to fully cure and must be kept wet to allow chemical reactions to occur and to prevent cracking.
These are just a few of the many possibilities of casting material. We have not addressed any additives that can improve the materials listed above, such as metal powders that can be added to transparent resins to make metal such as cold molds. Before you start your casting project and plastic mold, it is important to do your research and even talk to an expert. They can put you on the right path before you purchase expensive casting and casting material.