Most jewelers are familiar with chemical etching, which utilizes an etching mordant made from various acids. There is, however, an alternative method available to jewelers called electro-etching.
In my own home studio, electro-etching allows me to etch fine, detailed patterns and drawings into a variety of metals, without the risks associated with chemical usage, cleanup, and storage. Electro-etching requires more equipment, but does not require the acid etching mordants. Both chemical etching and electro-etching have their pros and cons. Here are few things to consider when using either chemical or electro-etching to etch your own creations.
Chemical Etching: What You Need to Know
Chemical etching does not require too much in terms of equipment, but you do need a nice, safe place to etch, one that is free of clutter, children, animals, etc. due to the exposed corrosive chemicals.
To get started you will need:
- A plastic tray. With some chemical mordants, you may use a glass tray, such as a Pyrex® (or any generic, oven-safe dish).
- An etching mordant based on the base metal substrate you will be etching. Ferric chloride is most commonly used with copper, and nitric acid with silver; there are others out there that you may prefer to use because they might give a better etch, work better with your mask material, or are just easier to ahold of.
- Some kind of mask material. Masking your design can be tricky, and depending on the acid you use, your design may require a stronger mask. Masks can be printed on peel-and-press sheets, or on other transfer papers that use heat to transfer toner onto metal. Sharpie® (or generic permanent markers), paint pens, lacquers, and asphaltum are other mask materials that are commonly used for chemical etching.
- Other materials such as plating tape, electrical tape, or duct tape will be needed to cover the back of the metal plate to prevent contact with the chemical mordant; these can also be used to help suspend the piece on the top of the solution during the etching process.
Chemical mordants are created using strong and dangerous chemicals. When using chemical mordant, it’s very important to read all the label warnings and safety precautions, including first-aid advice. Prior to etching, you should educate yourself about what to do in the case of a spill and/or skin contact. It is also important to know what type of protective clothing should be worn during the etching process—such as rubber gloves and a rubber apron—as well as recommended ventilation and respirator use.
Most chemicals used during etching are corrosive and can cause burns; it’s important to keep the appropriate neutralizers handy. Chemical storage and disposal is important to consider when working with etching mordants. This information can be found on the SDS for each chemical and, if you have any questions, please contact your local hazardous waste personnel before putting any chemicals down the sink!
Electro-Etching: What You Need to Know
Electro-etching uses electricity rather than chemical mordants to etch metal. Electro-etching requires a power source, such as a rectifier, along with positive and negative leads, a stainless steel pan, an electrolyte and a few consumables. Sherri Haab’s E3 Duo™ Electroforming & Etching Master Kit is a great way to get started with electro-etching.
Instead of strong acid mordants, electro-etching requires milder chemical solutions, such as copper sulfate, silver nitrate, or other dry chemicals, which are most commonly found in the fertilizer aisle at your hardware store. These chemicals are added to water to create a fairly harmless solution. The power source or rectifier provides electricity to the masked workpiece. Masking the workpiece still has its challenges but, without a strong acid attacking your masks, masking can be easier. Transfer papers last longer in the electrolyte solution during the etching process, as do other lacquers and paint pens. UV paper can be used for a very clean and crisp image transfer although additional equipment is required to use this paper.
Since most electrolyte solutions do not include strong chemicals and can be re-used over and over again. For instance, when using the copper sulfate, the copper drawn from the unmasked areas of a workpiece is transferred through the electrolyte to the bottom of the stainless steel container. The copper will actually build up and can be scraped and pulled off from the bottom of the pan and then recycled. The electrolyte solution can then be filtered through a coffee filter to remove any large particulates, stored in a jar, and used again. Be sure to read the proper handling and storage information included in the instructions for each electrolyte as they may vary.
Whether you choose to use acid etching mordants or an electrical power supply, both methods can produce an excellent detailed etch on a variety of metal substrates. Got questions or need some specific information? The Rio Tech Team is always just a phone call away (800-545-6566). And, after you try some etching on your designs, post a photo here to show us your results!