Establishments during this trade manufacture steel by melting ore, scrap metal, and other additives in furnaces. The molten metal output is then solidified into semi-finished shapes before it is rolled, drawn, cast, and extruded to make the sheet, rod, bar, tubing, beams, and wire. Other establishments by Structural Steel Supplier in Singapore make finished steel products directly from purchased steel. The least expensive technique of constructing steel uses trash as its base. Steel scrap from several sources — such as previous bridges, household appliances, and automobiles — and other additives are placed in an electric arc furnace, where the intense heat produced by carbon electrodes and chemical reactions melts the scrap, converting it into molten steel.