Just for copper, waste air conditioning tubes, transformers, inductors, computer cooling fans ... are all ready-made. ...
It is said that if copper burns at high temperature without the protection of inert gas, it is easy to produce copper oxide and its color is dark and pale, and the color of the ring produced is poor ... After copper oxide, copper and sweat are exposed to the air, the next step will be to produce green patina.
In addition, there seems to be no standard ring mold designed for copper. If a gold or silver mold is used, the required amount of copper needs to be recalculated according to the density of copper.
If it is really made, a layer of zinc can be plated by replacement method, and then the copper-zinc alloy can be fired at low temperature, and the color will be close to gold. Hehe ~ The required sulfuric acid can be bought in chemical stores, and zinc can be obtained by disassembling zinc-manganese batteries. It's just that the weight of copper-zinc alloy with the same volume is only half that of gold ~ If you are awesome, you can pack lead in it, and the average density is the same as that of gold, haha ...