What percent germanium do I use? Can I use sterling casting grain and add it? Or starting with fine silver, what other metals do I use and in what percentage by weight?
Judy H
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Following this out of interest
[This is a revision because there was an error in the first post.]
Creating a silver alloy with germanium is an intriguing idea, particularly for its tarnish-resistant properties. You’re probably already familiar with Argentium Silver, which incorporates germanium and is commercially available, making it ideal for small shops. Argentium offers consistent quality, ease of use, and the tarnish-resistant qualities you’re after, without the hassle of trying to create a custom alloy from scratch. It’s also a patented and trademarked product, but if you developed a similar alloy for your own use, there shouldn’t be any legal issues as long as you keep it private.
That said, Argentium Silver is roughly 20% more expensive than standard sterling silver casting grain, which could make creating your own alloy more tempting.
To address your question: Argentium Silver typically contains 1.2-1.5% germanium. Over the years, the formula has been refined to improve its working properties, making it more similar to traditional sterling silver. The current composition of Argentium Silver is approximately 94% silver, 4.8% copper, and 1.2% germanium.
The main issue, as I see it, in producing your own alloy is consistency. Even a slight variation in germanium content and mixing will affect the alloy’s properties, including tarnish resistance, workability, and durability. Like homemade silver solder, it can hardly be as consistent as that produced by a mill.
If you wanted to create a 30-gram batch of alloy with 1.2% germanium, you’d need 0.36 grams of germanium. Most dedicated jewelry scales that are now widely available would be accurate enough—a calibrated carat scale would be better, as 0.36 grams equals 1.8 carats.
If you’re still interested in experimenting, you’d need to start with fine silver and carefully measure your copper and germanium additions.
Good luck, and let us know how it goes.
The reason for the question is that I have some germanium and thought I’d give it a try. Is there likely any special handling - like when to add the germanium - does it need to be added late, or early and any issues with oxidation??
Judy H
Yes, like silver and copper, germanium can oxidize when melted. It reacts with oxygen in the air to form germanium dioxide (GeOâ‚‚). This is what helps prevent firescale in the alloy, so at least for the germanium, it should not present a problem as it melts into the silver and copper and will actually help avoid oxidation of the silver and copper.
Use a reducing flame when melting and keep the crucible in the flame to minimize oxygen exposure. Like any standard melt, do it as quickly as possible to help reduce oxidation.
A flux such as borax can be used to protect from oxidation.
Silver melts at a slightly higher temperature than germanium, but I would put the germanium in last after the copper and silver have melted together. It’s a small amount and should melt quickly. Be sure to stir with a graphite rod to make sure everything is incorporated.
Monitor the temperature carefully to avoid overheating the alloy.
I would advise that you contact James Binion. He is “Da Man” when it comes to metallurgy.
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the melting point of germanium is 1,721 degrees F…silver, 1,762 F, just slightly higher, copper at 1,983…argentum is 1,706 F… 1,800 F is cherry red… making your own alloys can be tricky for consistency… don’t overheat beyond cherry red, agree with last post to add germanium last, using a slightly reducing flame. Use casting flux with added powdered charcoal to prevent oxidation, work fast within the temperature contraint and mix well… avoid remelting as much as possible, preheat a CLOSED mold and be ready to pour immediately…