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Cast Iron Pot: a Kettle Moulded in Loam, Bottom Up (Bolland, The Iron-Founder, 1892)
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4. November 2026NO
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Cast Iron Pot: a Kettle Moulded in Loam, Bottom Up (Bolland, The Iron-Founder, 1892)

How a founder moulds an iron kettle or pot without a pattern: a brick core is built and coated with loam, swept to the inside shape with a turning board; a layer of sand swept on top stands for the metal's thickness; the cope is built over it, and the space the sand stood for is filled with iron. Bolland's example is an 8 ft kettle 1 3/4 in thick; the same steps serve any size. Variable: the size and wall thickness, set by the sweeps. Source: S. Bolland, The Iron-Founder (1892), pp. 180-183. Unknown: the loam mix and drying. Picture: Fig. 161 of the book.
Expert
Unknown

Instructions

1

Build and sweep the core

Set the core on a foundation plate strong enough to lift it without springing: a plain plate at least 3 in thick, or a ribbed one 2 in thick. Build the core of bricks in open, coarse mud, bricks well apart so air passes, with half-bricks crossing the joints on the top course and a tie-course here and there. Scrape the joints, rub on soft loam and sweep it to shape as you go round; the first sweep also strikes the flange, the guide and the seat for the cope ring. Finish with a skimming coat of the same loam sifted fine. Ours: sand and clay for the loam. Not given: the loam mix, the size.

Tools needed:

Iron CastingsIron Castings
Fired Clay BricksFired Clay Bricks
SandSand
Raw Clay from DepositRaw Clay from Deposit
Timber PlankTimber Plank
TrowelTrowel
Unknown DimensionsUnknown Dimensions
2

Strike on the thickness

When the loam is hard enough, change to the thickness sweep. Ram fine-sifted old sand at green-sand temper on by hand from the bottom up, sweeping carefully, dampen and slick it, leaving it about 1/16 in clear of the sweep, and press the flange corner sharp with the trowel. Have all the skinning loam ready first; it must be done in one pass. When it is hard, oil it all over and throw on parting sand. Ours: linseed oil.

Tools needed:

SandSand
Linseed OilLinseed Oil
Parting DustParting Dust
TrowelTrowel
3

Build the cope and gates

Set on the cope ring and build the cope over the thickness, best with building rings and packing so it can be bound down under a cross at once. Bed plates on the sand and bind them down with the cross or binders. Put the riser at the top and enough 3/4 in runners round it, in a circle about 30 in across, to fill the mould quickly. The sand thickness stands for the metal. Not given in these pages: lifting the cope to take the thickness off before closing.

Tools needed:

Fired Clay BricksFired Clay Bricks
Iron CastingsIron Castings
SandSand
TrowelTrowel
4

Vent and pour

Cut two gutters from the centre of the pit to the outside, sloping gently to the centre, and just before casting pour a little iron down to warm the air so the core gas draws off. Do not fill the trench with shavings and wood, which flash and crack the core. Fill the riser basin with soft straw or hay held down by a dry brick, so gas escapes but no rush of air damages the crown. Pour the iron through the runners. Ours: pig iron melted in a cupola.

Materials for this step:

Pig Iron IngotsPig Iron Ingots1 the kettle

Tools needed:

StrawStraw
Cupola FurnaceCupola Furnace
Foundry LadleFoundry Ladle

Materials

1

Tools Required

12

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