Young People's Page


| November/December 1970



Torque Power Live Steam Models Hyattstown, Box 144-D R. F. D., Ijamsville, Maryland 21 754

Hi There Young Engineers:

This article will be the first of several technical articles on subjects related to the steam engine hobby. This one is on foundry work. I am going to try and gear this article on foundry work so that any young person interested in the building of model steam engines can easily make his own castings. I will first give a little history on foundry work.

Foundry work goes back to the Old Testament times when in the day of Moses the children of Israel cast the Golden Calf. As to when the first casting was ever poured, it is not known. The basic means of foundry work has changed very little in all the time the art has been known. There has always been two ways of melting metal.

One is a cupola in which the fuel (coke) and metal (iron or bronze) are mixed together. The cupola is an iron or brick structure in which the fuel and metal are placed after a starter fire has begun. Near the bottom of the cupola are vents where air is forced in by a blower. At the bottom there is a hole to drain the metal out. This hole is kept plugged up by mud jammed into the hole along with a rod. When the rod is pulled out the metal will flow out. To reseal the hole while the metal is flowing, mud, again, is placed on the end of a rod and quickly jammed into the hole. The heat of the metal quickly dries out the mud plug. The metal being mixed with the fuel is melted as the fuel burns and runs to the bottom of the cupola. The liquid metal at the bottom, in time, floats any unburnt fuel and ash up to its surface, leaving a pool of molten metal which is drained into the molds. The level of the molten metal must not rise above the air vents. A good foundry man keeps careful account of just how much metal is placed in the furnace so that it will not overflow. This type of furnace is probably the oldest type known, first being made of brick and then iron lined with fireclay.

The second is a clay pot called a crucible in which the metal is placed. The crucible is then placed in a hole in the ground which is lined with brick. The fuel (coke or coal) is burned around the crucible. Air is forced through a pipe to the bottom of the brick-lined hole in order to burn the fuel. The crucible is picked up by a pair of tongs and the molten metal is poured into the molds.