As you know from the school chemistry course, copper is a metal, in the periodic table of DI Mendeleev is numbered 29. Copper has excellent thermal conductivity, has a beautiful reddish tint. Therefore, this metal is often used for electrical work and jewelry.
Instructions
Step 1
Most often, copper alloys, bronze (copper + tin) and brass (copper + zinc) are used for work. Copper alloys are more ductile and stronger than copper itself, and have a lower melting point. Pure red copper is a rather expensive material, and, moreover, it is very unstable. In air, it quickly oxidizes and becomes covered with a film, patina under the influence of moisture. Due to the high melting point (1000-11000 C), copper smelting at home is difficult. Although everyone can make small copper ingots.
Step 2
Use a tin can and stucco to make a mold for an ingot. Dilute alabaster with water, pour it into a tin container, make an impression of the desired shape. After solidification, bake the ingot mold at a temperature of at least 1000C in a conventional oven to exclude vaporization when pouring copper.
Step 3
Put a piece of copper (preferably large - less oxide) in the cavity of the mold, direct the flame of the oxy-fuel burner at it from above. When heated, the copper will melt, take the shape of an impression, i.e. the desired ingot. To improve the properties of copper, you can add a piece of brass or silver to the ingot.
Step 4
If you notice small cavities in the ingot, voids formed by air bubbles, the ingot should be hot forged. Copper is a soft material, so it is well forged. For hot forging, heat the copper on a conventional gas burner or blowtorch until it glow red. Then, using a small anvil and a hammer, shape the ingot into the desired shape, get rid of casting errors. When the copper cools down, the luminescence decays, the forging must be suspended and the ingot must be reheated.
Step 5
This method can be used to make a small ingot. If more copper is needed to melt, more sophisticated equipment, a muffle furnace, graphite or cast iron crucible should be used. Copper is poured into a crucible with borax and boric acid. Then the crucible is covered with a piece of fireclay bricks and placed in a muffle furnace. After the copper has melted, a piece of brass is added to the crucible to improve the casting quality of the melt, mixed, the sludge (such as foam on top) is removed and poured into the chill mold (mold).
