Aluminum Bronze Alloy
Aluminum Bronze is an alloy of Copper and Aluminum. It is stronger than copper and has a goldish hue that makes it desirable. There are different compositions for various applications, but in this video I went with 90% Copper (Cu) and 10% Aluminum (Al).
Smelting Preparation & Pouring Temperatures
In order to alloy, melt, pour and mold metals you need to know their pouring temperatures, and if going for a specific size, the density of each metal. As part of the preparation, I created and implemented a chart for most base, precious and alloy metals up to 2700°F or 1482°C (slightly over the nearly 2300°F or 1260°C my furnace can handle). Nickel melts at just above this temperature and cast Iron around 2350 for instance.
The pouring temperature must be higher than the melting temperature for 2 reasons. First, a higher temperature will allow you time to remove slag, remove the crucible from the furnace and pour. Second, depending on your mold, you will need the molten metal to remain in the liquidus state longer to enter all the crevices of your design before solidifying. Typically, I will pour about 90°C over the melting temperature.
Alloying is pretty straightforward, though there are different methods people use to accomplish this. One way is to put your highest melting point metal in the furnace first (i.e. Copper), then add the second and other metals after it melts (i.e. aluminum). My method involves adding all of my metals to the crucible and bringing them all up to temperature at once. After your metals have melted, give them a stir, removing any slag and reheat them for a couple more minutes before pouring.
Smelting Equipment & Recommendations:
ToAuto 3KG Electric Furnace: https://amzn.to/3rdn4Sz
Vevor 10KG Propane Furnace: https://amzn.to/3rdnd8z
CastMaster 10KG Propane Furnace: https://jerokiahdarr.com/castmaster10kg
Printers & Mold-Making:
Disclaimer: Smelting is dangerous and should be done with a healthy respect for the temperatures along with an understanding of molten metal, gases and toxins in certain metals. Due diligence is very important before any melting should be done at home. Have proper PPE and fire extinguishers, pre-heat molds and be aware of mistakes that can cause injury or even fatalities.