Investment casting, or the lost-wax process, is one of humanity’s oldest technologies.  A wax master model is made, and repeatedly dunked in liquid clay slip then dried.  Each dunk adds a few millimetres of clay until the wax master is completely encased in a solid clay surround.  The result is fired in a kiln, which melts then burns out the wax, leaving a perfect clay mould.  Into that molten metal is poured to create a metal version of the wax original.

Instead of a wax model, one can use a PLA 3D print.  As long as natural PLA with no additives is used it too burns out completely from the clay mould on firing.

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We have started experiments with an aluminium foundry.  It’s made from an old bucket into which we poured plaster and sand, with a plastic flower-pot in the middle to make a dent for the fire.  (We know that plaster and sand is not an ideal refractory material, but it’s what we had.)  At the side is a steel tube for the air blower, which is an old hair dryer.  The tube leads into the bottom of the flower-pot hole.

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As our first experiment we melted 100g of old drink cans, crushed so they would fit in a crucible we got from Ebay.  At this stage we just wanted to check that we could melt the aluminium reliably.

Next we’ll do a print then cast it in aluminium…

Fire and Fury

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