Micro Foundry Progress – Crucibles

I have been sporadically experimenting with my electric micro foundry setup for almost a year.  Recently I have been trying different crucibles.  My first crucible was a mini terracotta pot.  (I don’t know where the pot I used came from but I have not been able to find another one the same size without a drainage hole.)   I have also used a porcelain crucible (from Ax-Man) and a ceramic shot glass that I picked up in Las Vegas.  The terracotta pot has some significant cracks and chipping after a couple of furnace runs so it has been retired from use.  The porcelain crucible shows some chipping on the top edge.  Probably from being manhandled by a pair of pliers during the pour.  The ceramic shot glass seems to be holding up the best so far.  I don’t see any structural damage after a couple of runs in the furnace.  Before I used it I was a little concerned about the design on the side of the shot glass being a starting point for a crack but so far so good.

Casting small parts in sand is a little more sensitive that larger parts.  At least it seems that way since the small imperfections are a more significant portion of the end casting.  I tried the small toy airplane (red) in the picture above a couple of times.  both times the plane was only partially formed.  The tails were too short on one and the wingspan was too short on the other.  I will see if I can’t work out some of the bugs in the future.  Below are some pictures of my micro furnace in action and some in process pictures of a Yoda and toy plane.  I am using old aluminum nails, that I was given, for the raw material in my my micro foundry.  Most of my other scrap aluminum would need to be cut down significantly to fit.