Most mass marketed chocolate molds sold today are made with serious technology. Sophisticated CAD/CAM computer programs, engineered food grade materials, and expensive machinery. Like everything else, that wasn't always the case. Chocolate molds have been around for hundreds of years and the process of making them has gone through drastic changes. One thing that has not changed is that, for some, the molds are still considered to be works of art.
Before the use of plastics, chocolate molds were made of metal. Some were cast metals made by foundrys and others were made of sheet metal that was stamped around plaster models. Whether cast or stamped, the plaster models were hand sculpted by artists. They were very intricate. Most of the older molds were made in Germany and France. Metals such as tin, tin coated copper, silver plated copper, nickel steel, nickel coated metal, aluminum, and stainless steel were primarily used. Probably the most noted mold maker was Friedrich Anton Reiche. The Reiche molds were and still are in demand because of their variety and beauty. In the 1930's they had as many as 50,000 different molds.
Today, collecting antique chocolate molds has become both a hobby and business for many people. There are alot of people selling them over the internet, at auctions, shows, and eBay. Many of the molds now sell for hundreds of dollars. Some are kept for their simple beauty, others are used to make chocolate and other types of art. Some people have made plastic replicas of the vintage chocolate molds. These can be purchased for much less money and produce the same chocolates.
If you are buying old chocolate molds and intend to use them for food purposes, please be sure to check them first. The coatings can wear over time. This can cause rusting or exposure to unhealthy materials. It also makes it very difficult to remove the chocolate.
For more information about the history of chocolate molds, you might consider reading some books written by Wendy Mullen. She has written several books about collecting antique chocolate molds. Her books are well known by collectors for their historical presentation, pictures, tips, and listing of current values.