I've cast several rings using Argentium Sterling®. I haven't had much to say because there has never really been any problems or strange situations. Here are some of the things to remember when casting with Argentium Sterling®.
Temperature: 1750-1800 deg F. is recommended for casting (casting by sight is not recommended). Unfortunately I don't have the equipment the accurately gage the temperature of the AS so I must go by sight. I have tried to go with the lowest temperature that I can. Remember that if the metal looks yellow or light orange, it is too hot. I have been casting in low light conditions and heating it just until I know all the metal is fluid. The metal at that temperature has an interesting orange glow. One thing that has not been a problem for me is pitting (a common problem using regular Sterling silver). It is my guess that the problem has been lessened, at least in part, due to the lower casting temperatures.
Contamination: As recommended when fabricating with AS, do everything you can to prevent contamination from other alloys. Use a separate crucible, and when it comes time to polish, use buffs reserved only for AS, don't switch between AS and regular Sterling. AS seems to easily pick up copper from contaminated surfaces.
Oxygen: As you would with regular Sterling, protect the alloy from oxygen. I will usually use a pinch boric acid as I am heating the AS to protect it.
Hardening: Once the item is cast, I like to allow the flask to cool to room temperature before removing it from the investment. Cooling to room temperature in this manor makes the piece very hard (you should notice the difference when cutting off the button). The piece can be made only slightly harder if hardened using the precipitation method.
Temperature: 1750-1800 deg F. is recommended for casting (casting by sight is not recommended). Unfortunately I don't have the equipment the accurately gage the temperature of the AS so I must go by sight. I have tried to go with the lowest temperature that I can. Remember that if the metal looks yellow or light orange, it is too hot. I have been casting in low light conditions and heating it just until I know all the metal is fluid. The metal at that temperature has an interesting orange glow. One thing that has not been a problem for me is pitting (a common problem using regular Sterling silver). It is my guess that the problem has been lessened, at least in part, due to the lower casting temperatures.
Contamination: As recommended when fabricating with AS, do everything you can to prevent contamination from other alloys. Use a separate crucible, and when it comes time to polish, use buffs reserved only for AS, don't switch between AS and regular Sterling. AS seems to easily pick up copper from contaminated surfaces.
Oxygen: As you would with regular Sterling, protect the alloy from oxygen. I will usually use a pinch boric acid as I am heating the AS to protect it.
Hardening: Once the item is cast, I like to allow the flask to cool to room temperature before removing it from the investment. Cooling to room temperature in this manor makes the piece very hard (you should notice the difference when cutting off the button). The piece can be made only slightly harder if hardened using the precipitation method.
