Sheet metal can be made from a variety of different metals including aluminum, steel, copper, brass, nickel, tin, sterling silver and titanium. No matter what type of metal is used, the first step is to melt the metal in a container called a crucible.
When the metal is completely melted, it is poured out of the crucible and into a rectangular mold. The metal must be kept hot as it is poured into the mold so that it does not begin to harden outside of the mold.
When the metal has cooled completely, it is taken out of the mold. We now have a rectangular block of metal known as an ingot. The ingot is then dipped into a mixture of chemicals to be cleaned; a process known as pickling.
Once the ingot has been cleaned, it is put through a press. The press consists of two large rollers that thin out the metal. The press rollers are then moved closer together and the metal is run through again. Ingots may have to be run through the press several times before they reach the desired thickness.
As the ingot is run through the press the metal will become increasingly harder. It may be necessary to anneal the metal several times throughout the rolling process. Annealing the metal consists of heating it up and then pickling it again. During the annealing process the metal is only made warm-it is not melted again.
After the metal reaches the desired thickness, it is either shipped flat or rolled into a coil. Finished sheet metal is anywhere from .05 millimeters to 15 centimeters thick.