What is Casting Molds
Casting molds are an essential part of the metal casting process as it will be used to shape the final result. Nearly all metal casting methods will use some type of mold. The standard mold will consist of a cope and drag that when together is called a flask. The mold itself can be constructed of several materials depending upon the casting method.
Most molds will be made from latex, fiberglass, sand, and even metal. Sand molds are the most popular since Sand Casting is commonly used in small home foundries. In Permanent Mold Casting, the mold is created from metal. Most molds can be used over and over again, but not all of them. Certainly the metal molds can be used multiple times without loosing any quality from the finished product. However, molds created using sand or other materials will not have a very long shelf life. This is not generally seen as a huge problem just a minor annoyance since mold making is relatively cheap and easy.
No matter what material the mold is made from, the basic construction is pretty much the same. The molding box is called the flask which has a cope, the top, and drag, the bottom. You will then fill the flask with the molding material and then place the original into the mold. So, if you want to cast a tiny metal elephant, you will place an original of the elephant usually made from clay, wax, wood, or even metal into the drag of the flask. If this is done in sand you will ram the flask until the sand is packed tightly around the original. The top of the flask, the cope is then placed on and more molding material poured in. The entire flask is then rammed or vibrated making sure everything is packed in nice and tight.
When the molding material is dry, you will remove the flask and carefully split the mold to retrieve the original, in this case the tiny elephant. Now, if you want to make sure that there are some empty spaces in the cast to be finished then you will place cores into the mold. The cores are made of sand or wax.
The type of mold used depends heavily on the type of aluminum casting, alloy casting, and complexity of the pattern to be cast. Metal molds have little use in small foundries unless you plan on casting a lot of tiny metal elephants.
In some cases, pre-made molds can be found in hobby shops or through company casting companies. Usually, pre-made molds are used in miniature castings. Many individual metal casters prefer to make their own molds since it is inexpensive and allows them greater control over the finished casting.
Metal casting involves several sets of skills and mold making is one of these skills. Mold making is an invaluable skill for metal casters as it is so very important to the casting process. Not only are molds used in metal casting but in other casting types as well. Resin casting, aluminium die casting, magnesium die casting and other plastic molding requires a mold as well. The flask can be made of wood, metal, and in some cases those toy building blocks, we all know the type. As long as the flask can hold the mold material until it dries it can be used.
Every metal caster should learn how to make a mold instead of relying on others. It’s not only about independence but about saving money as well. Making your own plastic molds is just cheaper.