Thursday, March 24, 2016

Sand Casting with Aluminum

Ok, now this little project is getting real ;-)

We started with the aluminum ingots we'd made a few days ago.  They heated up quickly with much less junk.  We used the same crucible, so most of the junk in the metal was left from our heating the cans and brass cases.  The best part?  Cutting out foam forms!  We picked up a big sheet of foam from the Dollar Store, and with an inexpensive cutter off ebay (foam cutter $2) it was so easy to cut out some arrowhead shapes.  Even some 3D shapes were easy with glue.

We even tried a few 'exotic' arrowheads, including some 3D Fire Cage Arrowheads.

We buried the foam in play sand in a small tupperware bin.

Then we wett'ed the sand, and formed small cones around the foam to pour the aluminum into.  Here are some of the ingots we made last week to melt for the casts.

The ingots heated up quickly, and it was really cool to pour.  Again, because of the thin metal crucible we only got a single pour before the metal cooled too much and wouldn't pour well.

The casts turned out AWESOME!  Identical to the foam cutouts, and small details are in-tact.  We shook the sand well to make sure it settled into each detail.

These are a couple of "bird tip" arrowheads that Mongol archers would use for ducks and geese.

It was easy to cut off the overpour with a grinder and shape / sharpen the arrowheads.

We dropped paper on the overcast to show the kids just how hot the metal was before we pulled them and put them into water.

Unfortunately, the bigger, 3D casts of the Fire Arrowheads didn't turn out.  The metal seemed to have cooled too much to get down into the bottom of the foam mold.

Still, this was so much fun, we all agreed this is worth the effort to melt down cans.  Easy, cheap, and very engaging.  Highly recommend it.  Now we are having fun thinking of all the fun things to make...

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