Casting with Argentium® Sterling Silver - What does it look like?

When I cast with Argentium® Sterling silver, I use a torch (MAPP gas) and a centrifuge. After heating the crucible, I add the required amount of AS. After I have started to heat the Argentium® Sterling somewhat, I add a pinch of Borax. The AS melts quite quickly and as soon as it is fully molten, I release the centrifuge. Once the piece is cast, I let it air cool. This will help the Argentium® to become quite hard. Below is a picture of the button of a cast using Argentium® Sterling Silver.

After removing the cast from the flask, I bush it off with a toothbrush. The pictures below show a cast made from Argentium® Sterling Silver (left) and one made using regular Sterling Silver (right). The cast made from AS is somewhat gray but compared to the regular Sterling Silver, it is quite bright.

As you can see, there is quite a difference! The piece is ready to pickle.

Casting Flask Temperature: Additional Information

Peter Johns, the inventor of Argentium® Sterling, sent me the following information:

"We have found that flask temperature is not critical but metal temperature is. Metal temperature should be between 1740 F and 1800 F. Flask temperature should be what is normal in standard sterling for size and weight of the piece."

"If you are casting into a steel mould I always file all sides of the ingot before rolling. I always thought this was normal practice but I recently found somebody who was not doing it and they were not getting good results."

Question: Casting Flask Temperature.

Question: I am buying AS casting grain and will use it for vacumn casting wax models as well as ingot casting rough plate to mill into sheet metal. Do you have any cautions about casting and then milling the plate? What temperature do you have the flask at when you are ready to take it out of the kiln?

Cynthia Eid's article on Argentium® http://www.cynthiaeid.com/argentium_4-8.html should be very helpful to you. She recommends a flask temperature of below 1250F. I would recommend letting the crucible cool completely before removing the piece. Your casting will be very hard and you may see no need to precipitation harden it.

I haven't been able to afford a roller mill so I won't be much help there. Once you get comfortable with Argentium® Sterling you may want to try "super annealing". First dim the lights, then heat the Argentium® Sterling up to a slight red glow for a few seconds. Be very careful not to overheat the Argentium® Sterling. If you heat it as much as you would regular Sterling Silver it will be too hot. The trick is to quench the alloy just at the right time. Too late, it will only anneal as normal. Too soon, it will develop stress cracks. The time that is right is just after the red glow is gone when seen from a darkened room.

My First Allergy test with Argentium® Sterling

I had a friend volunteer to wear a pair of Argentium® Sterling earrings for me. She has only been able to wear high karat gold. Any gold under 18 karat would cause redness and swelling in her ears. She was also not able to wear Sterling Silver. Wearing Sterling Silver would result in redness and swelling in only an hour or two. Often this would result in infections.
My friend wore the earrings for over a week with no ill affects. She liked them so much she asked me to make her some more.
After the earrings were created, I put them in the oven at 250 deg. Fahrenheit for 20 minutes. I did this to attempt to raise the germanium oxide on the surface of the earrings. After the earrings were taken from the oven, I sterilized them with alcohol.
This test was by no means conclusive, however it was a very positive result for this one person. I am looking forward to doing more testing.

Hardness: Argentium Sterling® VS Gold Alloys

Today I decided to research a question I’ve been wondering about for quite some time now; how hard is Argentium Sterling® Silver compared to various karat gold? After doing quite a bit of searching on the WWW, I found two sites that helped me somewhat understand how the many alloys compare.
A great page to help understand the hardness of silver is from the Rio Grande Jewelry Supply. This page, from the Tips and Tricks section, was full of great information. One of the charts on the page shows the hardness in Vickers of Fine Silver, Sterling Silver, and Argentium Sterling® Silver. According to the chart Argentium Sterling® Silver can be both the softest and the hardest of the three.

http://www.riogrande.com/tips/all_tips.asp?offset=100

The technical guide offered at http://www.argentiumsilver.com/ gives the following information: After casting, if the flasks are left to air cool a hardness of approximately 100HV is achieved (this is what I prefer to do when I cast…it‘s very hard!). Precipitation Hardening will achieve a hardness of approximately 120HV.

Finding a good chart for gold (without getting into a bunch of technical data) was much harder. After quite a bit of searching, I found a web page that had a pretty good chart on the hardness of gold alloys. It’s from the U.K. so they show 9 karat gold instead of 10 karat gold as is used in the U.S.. The only thing I don’t like about this web page is it’s one of those that are hard to get out of once you are there.

http://www.24carat.co.uk/hardnessofgoldalloysframe.html

Note that gold doesn’t necessarily get harder as the karat weight goes down.