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These are mostly gold or a gold alloy (with copper or silver) and have been found to be largely cold hammered and sand-polished alluvial nuggets, although a few items seem to have been produced by lost wax casting. It is presumed that at least some of these items were acquired by trade from Colombia. [39]
West Mexican smiths worked primarily in copper during the initial period, with some low-arsenic alloys, as well as occasional employment of silver and gold. Lost-wax cast bells were introduced from lower Central America and Colombia during this phase, along with several classes of cold-worked ornaments and hand tools, such as needles and tweezers.
As the name suggests, the lost-wax method is to use wax as a mold, and heat it to melt the wax mold and lose it, thereby casting bronze ware, making the model (the outer layer of the wax model is coated with mud), lost-wax (heating to make the wax flow out), pouring copper liquid to fill the cavity left by the wax model, etc.
Tumbaga objects were often made using a combination of the lost wax technique and depletion gilding. An alloy of varying proportions of copper, silver, and gold (typically in a percentage ratio of 80:15:5) was cast. It was burned after removal, turning surface copper into copper oxide, which was mechanically removed.
A very important advance in glass manufacture was the technique of adding lead oxide to the molten glass; this improved the appearance of the glass and made it easier to melt using sea-coal as a furnace fuel. This technique also increased the "working period" of the glass, making it easier to manipulate.
The earliest gold metallurgy is known from the Varna culture in Bulgaria, dating from c. 4600 BC. [6] Silver, copper, tin and meteoric iron can also be found native, allowing a limited amount of metalworking in ancient cultures. [7] Egyptian weapons made from meteoric iron in about 3000 BC were highly prized as "daggers from Heaven". [8]
10th century BC – Glass production begins in ancient Near East; 1st millennium BC – Pewter beginning to be used in China and Egypt; 1000 BC – The Phoenicians introduce dyes made from the purple murex. [1] 3rd century BC – Wootz steel, the first crucible steel, is invented in ancient India; 50s BC – Glassblowing techniques flourish in ...
Window glass was formed by casting into flat clay molds then removed and cleaned. [12] The texture in stained glass comes from the texture the sand mold left on the side in contact with the mold. [12] Polymeric composites also made an appearance during this time frame in the form of wood.