The Beauty of Metal Etching
by Amy Harris, IQS Editor
If you start researching the topic of metal etching, one common application of this process is prevalent in the results – jewelry etching. It may play strongly into the stereotype of what it means to be female, but I unashamedly like pretty things – jewelry being one of them. Now, I work for an industrially focused company, am surrounded all day by industrial terms and topics, and I spend a good portion of my time writing about industrial processes (which, more often than not, are anything but pretty). So, if there is a way to incorporate something like jewelry into that world, I will attempt to do it. It is widely accepted that there are different ways in which people learn, but I think a commonality in the effective grasping of an idea or a new piece of knowledge is being interested in that idea or knowledge in the first place. I for one would far rather learn about the processes of acid etching, chemical machining or metal engraving by applying those methods to something that already interests me, such as jewelry. I do realize that an at-home jewelry maker experimenting with various chemicals and achieving amateur results is vastly different in both technique and precision to a high-technology state-of-the-art chemical milling process producing a semi-conductor chip. The principle steps of the methods, however, are similar enough to be connected.
In the process of chemical jewelry etching, a jeweler starts with a piece of metal, covers the parts of the metal he or she wants with a protective material or resistive substance, and then exposes the uncovered metal surface to a strong chemical or acid. The acid reacts with the exposed surface and begins to corrode the metal to create the desired pattern on the piece. The depth of an etching is controlled both by how concentrated the acid is and by how long the metal is exposed to it; the longer the exposure, the deeper the effect of the process. Once the desired depth of etch has been achieved, the piece is rinsed to remove the acid etching chemical and stop the corrosive action. The acid resistant material in the form of a paint, coating or tape material will also need to be removed from the piece to reveal the protected surface. The resulting contrast between the etched and un-etched should be a beautiful pattern, design, meaningful word or even a photographic reproduction on the piece of jewelry.
Etching has long been used for decorative purposes on objects such as ornaments, utensils and jewelry. Unlike the more commonly referenced process of metal engraving, metal etching relies on chemical corrosion to selectively remove metal from a surface area. It is a less precise method of marking than engraving for a pattern or design, especially when conducted by hand, as liquids form gentler lines and etches. However, not all metal etching uses chemicals and acids to create the patterns and grooves. Other precision methods rely on lasers or electrical discharge machining with the addition of CNC machining and computer programming to ensure the precision of the final product. The computer systems control the direction, pressure and speed of the process, allowing items as complex as electric circuit boards, brake rotors and fuel cell plates to be fabricated using etching. Etching tools such as burins or cutting tools can use abrasion and force to affect a surface and are also implemented in etching processes to achieve the desired grooves and patterns. The uses for the procedures of etching are almost as varied as the specifics of the procedures themselves. Etched products range from personal items such as sentimental jewelry to high tech pieces like miniature computer circuit boards to large scale architectural metal decorative pieces.
Images courtesy of Tech-Etch, Inc.
Both large and small applications use the simple process of metal etching in order to create something useful, necessary or beautiful from a piece of metal. There are a number of industrial processes to which I will neither be inclined to, nor have the opportunity to try my hand at; high intensity laser cutting and overhead crane operation for example spring to mind. And I have no desire to be able to fabricate a shock absorber or to understand the ins and outs of static eliminators. Yet, given a pendant, or an ornamental piece of metal and a chemical kit and basic instruction, I could easily be persuaded to dabble in metal etching, albeit at an amateur level. With the chance to create and design, I might walk away from the process with a less than perfectly decorated piece, but also with a practical and physical understanding of how metal can be cut and controlled with chemicals and acids. I am by no means ready to embark on a career in etching however and will leave the precision machining and far more important component fabrication to the experts with the fancy tools.