Taking The Mystery out of Metals – Part I
Welcome to the first installment of educational newsletters designed to help you sell better. This series is a result of our discussions with distributors around the country who have expressed an interest and need to learn more about metal products. We hope that you find these informative and interesting and we welcome your feedback.
Metals 101 – “How to think about metal manufacturing”
We often hear from distributors that selling metal products is difficult because of the wide array of manufacturing processes employed, materials used and the different names used throughout the industry. This edition is designed to give you an easy way to think about metals that can be applied to any metal product. We’ll begin with the basics.
Whenever you consider any metal product (lapel pins, key tags, buckles, coasters, suncatchers, etc) think about it in two steps: 1) shaping the metal and 2) adding color or an imprint.
Before we begin with shaping the metals and adding color we need to understand a bit about different types of metals.
Types of Metal
Brass – a mixture of copper and zinc and can be mixed from 90% copper to 60% copper. Brass polishes to a bright shine without significant distortion.
Pewter – a mixture of tin and antimony. Pewter is relatively soft material which has superior polishing characteristics. .
Zinc – one of the best metals to make light weight, strong items. It is much harder than brass or pewter and therefore requires more time to polish.
Precious metals – pure gold (24kt) is very soft. Gold used in manufacturing is mixed with other metals (mostly copper) to make it workable. Gold Filled is a way of getting the look of gold at a fraction of the cost. 2
layers of gold surround a layer of copper. Gold filled metal is sold based on gold content (e.g. 1/20th 10kt gold). Sterling is 99.9% pure silver.
Steel – is made from iron with different base metals added to give it better workability. It is the least expensive of the metals discussed.
At PinLine we work with all metals, including precious metals. This ensures that we can be a one-stop resource for your customers.
Shaping the Metal
There are 3 major ways to shape metal: Casting, Striking, and Etching. Casting involves injecting molten metal into a die that reflects an outline of the piece. Striking involves forcing solid metal into a die at high pressure. Etching is a process where specific sections of metal are “eaten” away by acids, leaving other areas untouched. Let’s look at each process in more detail.Types of Casting.
Three common forms of casting are jewelry casting (aka rubber mold casting), lost wax casting and diecasting. The major differences between the methods are the types of metals commonly used and the materials the dies are made from.
Jewelry Casting (a.k.a. rubber mold casting, centrifugal casting, spin casting) is used to make a lot of small jewelry items. Models of the item desired are created and pressed into sheets of rubber under heat and pressure. The rubber around the model liquefies and dissipates, leaving a cavity in the shape of the model. Molten metal (usually pewter or zinc) is poured into the center of the rubber mold while it spins at high rpm. The centrifugal force causes the molten metal to move out into the mold, filling the cavities. After the metal cools, the mold is opened and the castings are removed.
Lost Wax Casting is a way to create complex products that can’t be done otherwise. A model of the desired piece is made of wax and plaster is poured around the wax. The plaster hardens and is then heated to melt the wax out, creating a production mold. Metal (typically brass, gold or silver) is then poured into the plaster mold and after the metal cools and hardens, the plaster is broken away, leaving a reproduction of the original model.
Die Casting is typically done with zinc or brass. The metal is heated (zinc to 80OF brass to 1800F) and injected into a steel die. Once the metal cools, the die opens and the raw casting is ejected. Die casting machines run very quickly (approximately 400 cycles per hour) and reproduce the impression in the die perfectly.
Die striking involves three operations: 1) Blanking 2) Striking 3)Trimming.
1) Blanking. Plain metal (usually in long strips) is cut to reflect the outline of the piece. For example if you are producing a I” round coin, then I” round circles are cut out of the blank metal strips producing blanks.
2) Striking. The blanks are inserted into the die which contains a negative impression of the desired imprint. Next the metal in the blank is forced into the die under tremendous pressure. Pressure is created either by lifting a large weight high into the air and dropping it onto the blank (drop hammer) or by pressing the die against a surface slowly using a hydraulic jack mechanism (hydraulic press). The larger the item the more times it has to go through the pressing process. The overall thickness of the metal
could be shrunk 20% or more during this process.
3) Trimming. When the imprint is pressed into the blank under pressure, excess metal moves to the edge of the piece. Before finishing, this excess metal must be removed by trimming the piece back to its desired dimensions. This is done with the same trim tool (see above) that was used to create the blank.
Etching is a method of making a product without a die. An acid- resistant material is screened onto the metal using your camera ready art. Acid is applied and the areas that do not have the acid-resistant material are “eaten away” leaving the other areas un- touched. This makes a 2 dimensional item and is often used with color filling.
How We Can Help
At PinLine we want to help you sell more! One way we can help is to provide you with sample kits at no charge. Each kit contains clearly labeled examples of the processed described above to help you look like a “metals pro” in front of your customers.