How Charms are Made
Sure you've seen a lot of great looking charms that can fit any theme imaginable, but have you ever wondered where they came from? Time constraints being what they are, you know there is not some metal smith who is spending all day and night hammering out small charm after small charm to go onto your next piece of jewelry. But, they have to come from somewhere.
Here are a few different ways that charms are made.
Lost Wax Technique
The lost wax casting technique is a centuries old process of making metal items that dates back to the 17th century B.C. It was used by the Egyptians and other empires throughout the ages, and is such an effective system that it is still the preferred choice for many who are making pieces of jewelry to this day. The process is relatively simple.
First an artist creates a model for the design that they want to see made into metal. This can be carved in clay, wood or a number of other substances. Usually artists will chose a medium they are most comfortable with and can make the most effective and detailed design in. While you might think this would be the same design you will see in the finished project, the original model actually must be about five percent larger than the final piece will be.
Once the model is done, a flexible mold must be created. This is usually made out of a flexible vulcanized rubber that can handle high temperatures (up to 350 degrees or so, which will be the temperature of the melted wax that will have to be poured into the mold). When the two pieces are put together they will create the outside of the exact replica of the model.
Next, wax is poured into this mold to create a wax version of the original model (this piece of wax will eventually disappear and be replaced by molten metal).
Once the wax mold has cooled, it will need a shell before being melted down. Tubes of wax, called vents, will be attached to the wax piece that will stick out of the next solid mold that has to be made, so wax can be melted out and metal can be poured into the piece later on. Once the wax is in place, plaster will be poured around it to form the solid frame.
Now it's time to get rid of the wax and create a mold for the molten metal. The dried plaster mold is put into an extremely hot oven, hot enough that the wax then melts and can be poured out through the tube vents that were made in the plaster. Once the wax is gone, you have your mold, which is known as a lost wax mold.
Now it's time to make the metal piece. Whatever metal is going to be used to create the final piece will now be heated to it's melting point. That molten metal will be poured into the mold (through the vents) and left to cool. Once it has had sufficient time to harden, the plaster shell is broken away and the metal piece inside comes into view. It's not quite ready to be incorporated into a jewelry design yet. In addition to that perfectly detailed piece of jewelry, remember, those vent tubes are still sticking out of it. Those were also cast in the metal. They must be cut off, and then the piece will be buffed down and polished. Now it is ready to become a part of a fantastic jewelry creation.
A popular method for creating pewter charms is called die-casting. If you ever played with play dough as a child, and used a three-dimensional shape cutter, that is much what this method is. The pressure put on the die will make the metal into the shape the cutter or die wants it to be.
First, a mold, called a die, has to be created. This is a negative version of the piece. This is made out of a very hard metal that can withstand a lot of pressure and the extremely high temperatures of molten metal. It will also have to be strong enough to handle repeated experiences with that molten metal.
The two pieces of the die are put together, and held together with force. A machine usually does this. Then metal that is in liquid form is injected into the mold, to take on the shape and all the details in the die. The general rule to speed up the cooling process is to take the die filled with molten metal and dunk it into water. That cooling of the die transfers into cooling of the metal inside and helps it to harden more quickly. Once the liquid metal has become a solid, the pressure is released, the die is opened, and the completed metal design can be popped out. Before it is ready to hit the market, the new charm may need some trim work. It is possible some of that molten metal along the edges will be stuck to the design and may have to be sanded off. In addition a little buffing and polishing may also be necessary to give it the final ready-for-market look.At this point, charms can be put on the market as is, or some may get an additional finish of a gold-tone or silver-tone metal dip to make them look like the more precious metals, but be available at an affordable price.