Encyclopedia · Manufacture, materials, and testing

Rodman hollow-casting process

The Rodman hollow-casting process cast a large iron gun around a hollow, water-cooled core so it solidified from the inside outward, leaving the bore in compression and the gun far stronger.

Also known as: Rodman process.

InventorThomas J. Rodman
MethodCasting hollow around a water-cooled core
EffectBore surface set in compression; far stronger large guns

Casting from the inside out

In the older method a gun was cast solid and then bored out, so the metal cooled from the outside in and left internal stresses that limited how large an iron gun could safely be made. Thomas Rodman's process reversed this: the gun was cast hollow around a water-cooled core, so the iron solidified from the inside outward.

The result left the surface of the bore in compression and greatly reduced the internal strains, allowing iron guns of unprecedented size and strength, the great Rodman columbiads up to twenty inches in bore.

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