Meeting recap – Metal Casting


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:

Foundry hole

Repurposed vacuum

Filling the furnace with Charcoal

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.

Removing the original

Re-joining the mold

Removing the sprue pin

Setting down the mold

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:

Lighting the furnace

Still lighting the charcoal


Puddle of molten aluminum

Just as it was starting to get dark, we had enough liquid aluminum for the pour:


Aluminum after pour

Here’s a video of 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:

Original, Duplicate

Original, Duplicate (sprue still attached)

It was a grand old time. Can’t wait until next time!


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