A lot of alloy charts list aluminum bronze with a longer shopping list of metals. TheGrowingStack went the other way and blended just two metals, copper and aluminum, at 89 percent and 11 percent by weight. It was also a first attempt at this alloy, and the castings came out with a bright golden metallic look.
Everything was weighed on a digital scale to hit the target: 1780 g of copper against 220 g of aluminum, 2002 g all in. The charge drew on stripped copper wire, small copper pieces and an aluminum bar, with wire clippings, an aluminum ingot and a small aluminum button also in the pile. The melt ran in a graphite crucible inside a propane furnace lit with burning paper, and the packed metals were heated until everything melted and glowed. Crucible tongs handled the pour into three graphite molds, then the remaining metal was reheated for a fourth, tree-shaped mold.
The finishing sequence looks tidy. Each solidified casting came out of its mold with channel lock pliers and went into a metal bucket of water. Then it was clamped in a bench vise for the wire wheel, followed by white and red rouge on a motorized bench buffing wheel. The set is a bar ingot, an awareness ribbon, a skull medallion and a tree of life medallion, 1817 g combined, now resting on a wooden shelf beside earlier aluminum, copper and brass work.
The stated reason for keeping the blend to two metals is that the other alloying metals were not on hand. The open question is weight: the finished pieces run 185 g under the starting metal, and the maker flagged that loss without explaining where it went. That gap is the one thing I would most want chased down in a follow-up melt.
Project by TheGrowingStack. Watch it on their YouTube channel: