In this project I will show you how to make bismuth egg geodes. You will need:
- 2lbs of Bismuth
- Eggshells, blown, washed, and dried.
- Aluminum crucible,
- Propane torch,
- Oven mitts.
This process is dangerous. We will be using molten metal. Please wear eye protection.
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Step 1: Melting Bismuth
Bismuth melts at a relatively low temperature for a metal at 520.6°F (271.4°C). It can easily be accomplished with a propane torch. Heat the metal until it is completely melted. Dross will rise to the surface. Once the metal is all liquid scrape the dross off using your metal scraper. The surface of your metal will be silver for a short time and then it will quickly turn shades of orange, yellow, green, blue, and purple. These are different thicknesses of bismuth oxide forming on the surface of the molten metal. I am always amazed by how beautiful molten metal is.
Step 2: Pouring the Bismuth
This is probably the most dangerous part of the process so please remember to wear your eye protection and work carefully. Carefully wrap your eggshell with aluminum to catch the molten bismuth if the eggshell breaks. Next slowly pour the bismuth into the eggshell. This is where the art happens. You need to wait until the surface begins to harden at which point you will pour out the remaining molten bismuth. To gauge when the metal is ready I tapped the side of the egg and watched the ripples move across the surface of the metal. When the surface no longer rippled I knew the egg was ready to pour. Pour the remaining material back into your crucible.
Step 3: Crack Open Your Egg
Wait for your egg to cool enough that you can hold it in your hand. Then start cracking the eggshell. I found that tapping it on the corner of the counter top pulverized the shell without damaging the bismuth sculpture inside. At this point you can see what it looks like. If you don't like how it looks just melt it back down and try again.
Step 4: Enjoy
Here are a few different eggs that I made. Each one is unique.