Header Clamps

We have a rather nice model workshop at my school,
The newest feature is a small foundry that I wanted to learn to use.
I used one of the old rotten header clamps as pattern, but it had a lot of small rust craters that would drag out the sand when I tried to make the mould.
That was dealt with by covering the thing with a sheet of 0.5mm acrylic on the vacuum table. See the lousy cell phone video below.
Next up was packing the sand tightly around the pattern, flip the frame and gently remove the plastic with the old clamp in it. I now had one half of the mould, the other half was just flat packed sand. Clamp the two together and pour in some aluminium (720°C).
I think they look pretty good just out of the mold. The next thing to do is taking down the burrs and gates in tha lathe  which I have no idea about how to use yet.

The pattern is ready. The wrinkles in the plastic make good air escape channels.

Packing sand.

The cope.

The drag and cope.

The gate is covered with a handfull of sand to let the metal set.

Et voilá!

They're already looking way better than the original.