Vitreous Enameling

Q: What do jewelers mean by “enameling”? Is it the same as regular paint, or does it have to be heated in an oven? Is it the same as embossing?

A: Embossing powders are a plastic-based product, used in the printing industry. They are sprinkled onto wet printer’s ink, then the printed objects, such as business cards, for example, are placed under a heat lamp or similar source, where they fuse and create the look of raised-ink lettering or intaglio printing. Embossing has nothing to do with copper enameling, though there’s a passing similarity to the process (with a difference in temperature of about 1400 degrees…)

In copper enameling, (which is also the process jewelers use, although the metal underneath may be silver or gold) a powdered colored glass called enamel is applied to a metal substrate. It’s also called “vitreous” enameling, because glass is melted in the process. The glass is formulated so that its thermal expansion rates will match metals like copper or silver, allowing it not only to fuse to the metal, but to remain firmly attached to the metal when everything cools again. There are many types and colors. One notable distinction is between lead-free enamels and lead-bearing ones. Lead oxides allow a glass to melt lower, and can improve some other working properties, but make it less safe to use on items that may be used with food, or against skin. Lead-free enamels generally melt at higher temperatures, and are a bit harder to control. In the U.S., perhaps the biggest supplier is Thompson’s Enamel.

Thompson’s address is : P.O. Box 310, Newport, Kentucky. 1-800-545-2776 to leave a recorded order (VISA/MC only) or 1-606-3800 to talk to a live person.

Enamelwork Supply, in Seattle (206) 525-9271, carries a number of foreign brands, including French and Japanese enamels, which are usually lead-bearing, and are preferred by some experienced enamelists.

Another domestic manufacturer you might see is Amaco (American Art Clay co.). Mostly they produce clays and ceramic glazes, but they also offer a line of metal enamels. These work, and the little kits are inexpensive and handy, but they aren’t the finest product out there. Enamels are available in other forms than just powders. Threads and little chunks, for example, are often popular…

The heating for enameling can be done as simply (and crudely) as with a common propane torch, but with less than predictable results. Most people prefer to use an kiln. These ovens must reach temperatures of 1500 degrees F or a bit more. What they’re called depends on what you’re doing with it. If you’re a ceramist, firing pots and clay ware, chances are you wouldn’t be caught dead calling it anything other than a kiln. Same hot box, burning out waxes for casting into metal, gets called a burnout oven. In enamels, you often hear it called an enameling kiln, but it also can be called an oven. Whatever you call them, they are not the same as the home ovens used for cooking food. For enameling you’ll want one with a temperature readout, called a pyrometer. There are some simple ones sold without this, but they are harder to use. I’ve seen a little table top hot plate sort of thing sold for this purpose, but these are dangerous—you need a door that opens on the side, not on the top, so the superheated air inside won’t rise and burn you.

Almost any jeweler’s supply house will happily sell you a suitable kiln/oven. Most of these places will be happy to suggest and supply good books on the subject, and many also carry a variety of enamels. Your yellow pages is a place to start, as most larger cities have at least one jeweler’s supply house. The various firms already mentioned will be of help.

Here are some book recommendations from a post in this newsgroup I saved a couple years ago. Still accurate…

Enamel, Enameling, and Enamelists by Glenice Lesley Matthews

This book is very good with detailed instructions on metal preparation, and various enameling techniques. Several projects are included as well as pictures of works by different artists using various techniques.

Cloisonne Enameling by Felicia Liban

Good book on cloisonne enameling.

Enameling on Metal by Oppi Untracht

This book may be out of print.

First Steps In Enameling by Jinks McGrath

Basic introduction, also has projects.

by Peter W. Rowe M.F.A., G.G.