Making molds and creating objects out of acrylic resin is a lot of fun. You can create costume jewelry, toys, paperweights and a myriad of other items. Acrylic resin is very commonly used because it sets up quick, is easy to mix and is not difficult to work with. It's also a little more forgiving than other casting agents. There are alternatives to acrylic resin when you're making objects with molds. These alternatives may be slightly cheaper, but the processes involved can be much more complicated, not to mention toxic and dangerous. The article that follows will list several of the alternatives to acrylic resin.
Plaster, Alabaster and Concrete
Each of the alternatives to acrylic resin is slightly the same and the process to cast them is relatively the same. They are all mixed with water in equal parts and then poured into a prepared mold. Once they have cured the mold is removed and you are left with a hard statue. Alabaster is used as a means to mass-produce statues and figurines. Concrete is primarily used to cast larger items that are meant to be used outside. Plaster is the weaker of the three and possibly the most difficult to work with.
Slush or foam latex is used almost exclusively in the special effects world and specifically to make Halloween masks. Casts are made from people's heads using plaster and a wide array of other materials. Once the plaster cast is made the slush latex is mixed and then poured into the mold. When dry the mask can be removed and painted. This material can also be used to make soft figures and statues. It is a fairly expensive way to cast products and is also toxic due to a high amount of ammonia in liquid latex.
This very well may be the most widely used of materials to make products out of. Everything from silverware to toys to car bodies can be made using plastic. The most basic method is to use injection molding. Plastic sheets are warmed until pliable and then a vacuum pulls the plastic into a mold until the plastic hardens. This process is used to make plates, bowls and costume pieces. Liquid plastic can also be poured into molds, set and released to create solid products.
The process of melting metal ore down is called smelting. A master mold is made from metal and sprayed with a releasing agent. The metal ore is placed inside a container that is then either placed in a very hot oven or over a fire. The metal ore becomes liquid and you then pour into the mold. The ore does not take very long to solidify and a hammer is used to dislodge the item. Flash is then removed from the edges and the item is polished. This technique takes time to master, is messy and can be very dangerous.