Wow, what a fun meeting!
A lot of people came out; the tag line “melt metal” really piques your interest. We were in a race before the sun went down, and despite repeated mistakes, we were able to build a sand mold, melt some aluminum, and pour to create a duplicate.
Ken and I first dug a hole in the ground and built a cylinder of bricks within it. We positioned a steel pipe (for air flow) and then covered the walls in dirt. We used a broken vacuum cleaner as our air source, and charcoal as our fuel:
Next we rammed up a mold. In this technique, we build a sand mold in two halves, separable along the horizontal. We must have done this four times as the top half kept collapsing. Our problems: we didn’t have enough clay in the sand, we didn’t tamp the sand enough, and we didn’t use a parting sand between layers. Once we realized this, it got a lot easier.
Once we had that done, we got to start up the fire. The fire started slowly; the tape on the vacuum came loose and we didn’t get enough air at first. Soon enough, a good fire started, and our crucible turned bright red:
Just as it was starting to get dark, we had enough liquid aluminum for the pour:
We let it cool for a while, and when it came out it looked like this. Not perfect, but not too bad either:
It was a grand old time. Can’t wait until next time!