The Excelsior Project, 10: Saddle & Heads
Not everything goes as planned. The mold wouldn't release from the plug, and here the plug is destroyed in trying to save the mold. This whole "seat mold thing" has become very time consuming. In all, five molds are needed to make these seats...
Both molds ended up being undamaged, so that was a small cause for celebration. The yellow below is pattern-makers wax, because I need to allow for the thickness of the leather before the inner molds are started. The white (under the wax) is the gelcoat sprayed over the plug before the many layers of fiberglas are added. The pattern-makers wax has adhesive on one side, and a hairdryer is used to warm the wax slightly to help it conform to the shape of the mold. The heat also helps the adhesive to stick better.
The inner molds are done, and need to harden for several days before being removed from the outer molds. The excess will be trimmed with a diamond wheel, and the edges sanded smooth. Molds need to be at least 1/4" thick for good strength and durability...
Building the heads is one of the most exciting stages. As a kid out of high school I worked in an automotive machine shop and dreamed of making my own engine. Now is the time! Below is the fixture for locating the valves, which is crucial. The top plates hold the valve stems, while the heavy round stock further down the stems holds the valve seats in position for TIG-tacking. The 1/8" steel in the shape of a head gasket was laser cut.
The combustion chamber is taking shape. The five years I spent developing my Aermacchi road racer has turned out to be invaluable. I kept notes on all the engine modifications and specs, and that knowledge is used here.