How to Clean Casting Silver

When casting sterling silver jewelry, there will always be excess silver that was cut away from the cast piece. This excess sterling silver, along with silver that was left unused in the crucible after the casting machine stopped spinning, can be reused for future castings but first it must be cleaned. You can send this silver away to be commercially cleaned or you can clean it yourself.

Things You'll Need

• 5-gallon plastic bucket
• Stainless steel pan
• Tap water, warm
• Aquarium circulating pump (10 gallons per hour)
• Scrap sterling silver
• Crucible
• Torch
• Jeweler's tongs
• Safety glasses
• Gloves
• Apron
• Old small crock pot
• Jeweler's pickle solution

Instructions

1. Set a stainless steel pan inside the bottom of the 5-gallon bucket. This acts as a fireproof barrier so that, when the molten silver is poured into the swirling water and falls to the bottom, it won't melt through the plastic bucket.

2. Fill the plastic bucket with tap water. The water should be warm, just a little cooler than bath water. The level of the water should be 1/2 to 1 inch below the top edge of the bucket.

3. Hang an aquarium circulating pump that has a circulation of 10 gallons per hour over the edge of the bucket on the inside and plug it in. Circulating water creates better-sized sterling silver shot.

4. Place the silver to be cleaned in a heat-resistant crucible. A crucible is made from fused silica and clay. Put on protective goggles, gloves and apron and light a torch. Heat the metal until it's just above molten. Sterling silver melts at 1640 degrees Fahrenheit or 893 degrees Celsius.

5. Pick up the crucible with jeweler's tongs and pour the molten silver into the swirling water in the bucket. Take care not to pour any hot metal on the circulating pump, as it will melt the plastic of the pump.

6. Let the silver shot cool at the bottom of the bucket sufficiently before removing. The silver shot will not be perfect in shape but rather organic in shape and flat.

7. Put on the apron and, using jeweler's tongs, gently place the newly cleaned sterling silver shot into a heated crock pot filled with jeweler's pickle solution. Jeweler's pickle is an acidic solution used to clean oxidation, dirt and grease from metal to be used in jewelry making. Remove the shot after 10 to 20 minutes with the tongs.

Tips & Warnings

• If you use cold water in the bucket instead of warm water, you will end up with much thicker pieces of sliver shot.

• To discard the pickling solution after use, add baking soda to it. When the bubbles die away, it is safe to flush it down most drains.

• Molten silver is dangerous to work with. Take care not to spill any on your clothing or skin. Always wear eye protection, gloves and an apron.

• The small crock pot will not be safe to use for food after this. Use it only for future cleaning of casting silver.

References

• YouTube: Homemade Silver Cleaning
• Kitco: Melting Points of Various Metals and Alloys