Crucible Furnace: the Brass Founder's Sunk Coke Air Furnace (Larkin, 1907)

The brass founder's crucible furnace: a firebrick-lined pit sunk below the floor, fired with hard coke on an iron grating over the ash-pit, closed by a dome-shaped iron cover and drawn by a flue with a damper. The crucible sits on a firebrick in the middle of the fire, lidded, with coke banked round it, until the metal is melted. Result: a coke-fired crucible furnace for melting brass and bronze. Source: J. Larkin, The Practical Brass and Iron Founder's Guide (1907), pp. 96-99. Unknown: all sizes. Picture drawn by Youblob.

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说明

Build the pit

Sink the furnace below the floor. Line the inside with firebricks set in fireclay; use pure clay (white, opaque, oily to the touch), since iron oxide, magnesia, lime or black lead in brick or clay shortens the furnace's life. Close the ash-pit at the bottom with a hinged iron grating. Not given: sizes.

此步骤所需材料：

耐火砖1 lining

耐火黏土1 jointing

未知金属1 hinged grating

所需工具：

未知尺寸

Fit the cover and flue

Make a dome-shaped cover for the furnace top of cast or wrought iron. Lead a flue from the furnace with a damper in it. Not given: the flue size or height.

此步骤所需材料：

未知金属1 dome cover, damper

烟囱烟道管1 flue

所需工具：

未知尺寸

Fire it and melt

Burn hard coke broken to lumps the size of a fist. Heat the crucible bottom upwards in the fire, lift it out with the tongs, turn it upright and bed it on a slab of fireclay or a firebrick, put on its lid and bank the fire round it. Put the metal in, close the cover and open the damper for draught until the metal is melted. Black-lead crucibles last longer; clay ones must first be hardened by slowly raising their temperature.

所需工具：