Cynthia Eid SNAG News Technical Article by Cynthia Eid: Argentium Sterling Silver |
The Society of North American Goldsmiths
TECH NEWS
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1050ºF to build up a skin of oxides (which have a higher melting temperature than Argentium® Sterling).
I managed to get a few areas of lovely ripples, but nothing consistent. ENAMELING? There have been experiments with enameling on Argentium® Sterling Silver, but I don’t know of anyone who has had consistent success. It seems that it could be worth investigation, since Argentium® Sterling is sturdier than fine silver, and the temperature required for hardening should not damage enamel. HEAT HARDENING Heat at 580°F (299°C) for 45 minutes to 2 hours, and then air-cool. The alloy will not lose its hardness if left in the oven longer. (Since my oven goes only to 550°F, I usually heat it for an hour at 550°F.) Unlike many other alloys, it does not need to be quenched in order to be hardened. Should the need arise, the alloy can be softened by conventional annealing and then hardened again. ANTIQUING I have been using a commercial acidic solution, which is hydrochloric (or muriatic) acid, to “antique” my work made in Argentium® Sterling Silver. It works quickly and well. I like the way the acid types of “antiquing” patinas are always ready to use —no mixing, or heating up required. (Of course, it is important to use it very carefully according to the instructions and precautions. Have adequate ventilation, use gloves, eye protection, etc.!) I like to use liver of sulfur for copper and brass alloys, because of the beautiful range of colors, and the depth of the colors. However, for "antiquing"' silver, when I just want the recesses to have a black patina, I don't use liver of sulfur, because of its short shelf life. Some people report that liver of sulfur takes longer to work on Argentium® Sterling than for regular sterling. POLISHING Just as it is important to keep buffs used for steel tools separate from buffs used for precious metals, it is good practice to use separate polishing wheels for Argentium® Sterling Silver to avoid contamination from other alloys (residues left on the buff from another metal could be transferred onto the surface of the silver). If this is not possible, thoroughly rake the buffing wheels clean before using them for Argentium® Sterling. Of course, like the soldering boards, these separate buffs should be labeled, and stored separately from buffs used for other metals. Ultrasonic solutions should be neutral in pH (pH6-pH8) for any sterling silver, whether regular or |
Argentium®, since high alkaline liquids attack all sterlings. The metal can look etched or discolored, especially if the ultrasonic
is run very hot (over 120ºF). (I have also been told that ultrasonics, run with too much force, can attack any surface.)
Peter Johns learned the hard way that solutions labeled as neutral are not necessarily so. Use your own ph test strips
to check the ph. (Disposable paper strips areavailable at pharmacies and aquarium/pet stores, as well as on the web.) Since the final polishing of a piece made of Argentium® Sterling removes much of the tarnish-resistant germanium oxide layer, one may wish to heat the Argentium® Sterling to speed up the re-building of a protective germanium oxide layer. 250°F for 10 minutes is generally adequate. The immediate difference after this heating is invisible to me, but I am sure the difference shows over time. (If there is a little smudge, or piece of crud that got burned on during this 10 minutes, I use a Goddard’s Long Shine Cloth.) Like glass or any other metal, Argentium® Sterling can show fingerprints. However, I have noticed that the pieces on which I have wiped off fingerprints with a Goddard’s Long Shine Silver Cloth have stayed cleanest and are more fingerprint-resistant. It seems that the chemicals in the cloth affect Argentium® Sterling, enhancing the non-tarnishing properties--though I do not notice a film, nor any visible difference other than the polishing action. SAFETY If you are like me, you may wonder about the safety of germanium. I know that when I first heard about this sterling alloy, I was quite concerned about its safety (since I knew nothing about germanium!) I looked on the web at the MSDS for germanium, as well as for silver and copper. Since the lists of dangers for silver and copper are longer than the list for germanium, I feel that it is a safe component for sterling silver. My recent research for this article led me to this interesting statement: "Certain germanium compounds have a low mammalian toxicity, but a clear activity against certain bacteria, which makes them of interest as chemotherapeutic agents." 6 Naturally, one should always use safe work habits when working with any metal. Wear a dust mask and safety glasses for grinding or polishing. Use good ventilation for soldering, grinding, and polishing. Don’t eat or drink in the studio. Use common sense, and take precautions to take care of your health and safety. It is interesting to note that using Argentium® Sterling Silver could make many workplaces safer, since they will no longer need to use cyanide and/or nitric acids to deal with firescale if Argentium® Sterling Silver is used rather than regular sterling silver. |
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This technical article was first published by the Society of North American Goldsmiths in its newsletter, under Tech News. All SNAG members automatically receive the newsletter five times a year. To sign up for membership, go to www.snagmetalsmith.org, or (630) 778-6385.
| Cynthia Eid |
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