Back in the day when they built the original Shay locomotives the hundreds of castings were created by first making master carvings from wood. Skilled pattern makers would create complex wooden forms. Then they would imbed these wooden models in a special sand which was packed around them and then the wood forms were pulled out. The sand molds were fired in giant ovens to dry before they were filled with molten metal in the foundries. I toured an old pattern shop a number of years ago and was amazed by the awesome work I witnessed.
As we create our fun replica of the Shay we have easier ways to create these complex shapes. I did what I could bending and forming sheet metal and then welding things up. For the wheels, trucks, and hundreds of other smaller bits we went high tech. I designed the files in a 3D software called EnRoute, then sent the digital files to our CNC MultiCam router. Using a variety of bits (which I specified) it carved and cut the pieces from 30 lb Precision Board HDU. The computerized machine can work many times faster and much more accurately than I could possible do it by hand. The pieces are now in the process of being cleaned up and sorted in preparation for final assembly. It is quite the pile!
The process of finishing and assembling is kind of like putting together a jigsaw puzzle - only without a picture or instructions to go by. There is plenty of hand work and imagination required to make it all look real.
But even after it is assembled it still doesn't look like heavy metal. We have a cure for that! While everyone else I know uses paint to inhibit rust we have a very special paint that DOES RUST. It has minute metal flakes in it and after it dries we spray on a mild acid to make it rust. In a few hours our High Density Urethane looks like cast iron. It is pretty amazing stuff!
Stay tuned as it all comes together...
-grampa dan