METALS

Publisher Summary This chapter discusses applications of metals on a model traction engine and drinking cans. The most notable part of the traction engine made from copper is the boiler and its fire tubes. In full size, this would have been made from mild steel, and the use of copper in the model is a nice example of how the choice of material can depend on the scale of the structure. The boiler plates of the full-size engine are about 10 mm thick of which perhaps only 6 mm is needed to stand the load from the pressurized steam safely, the other 4 mm is an allowance for corrosion. It is found that although a model steel boiler would stand the pressure with plates only 1 mm thick, it would still need the same corrosion allowance of 4 mm, totaling 5 mm altogether. It is observed that as copper hardly corrodes in clean water, this is the obvious material to use. It is found that although weaker than steel, copper plates 2.5 mm thick are strong enough to resist the working pressure and there is no need for a separate corrosion allowance.