First attempt at casting aluminum in forced-air charcoal forge made of found material: two flower pots, cesspool grate, shop vac & muffin tin. Single purchase was $3 stainless cocktail shaker from thrift shop for use as crucible. Smelter performed very well. Using "Cowboy" brand lump charcoal, aluminum melt point (660C/1220F) was achieved 10 minutes after blower turned on. During pour it was discovered that temperatures had, in fact, exceeded 1360C/2550F, when stainless steel crucible failed and roughly half the melt drained out of several holes in the base (producing the puddle visible in second to last photo). This unanticipated, extreme heat cracked the ceramic lid and both inner and exterior flower-pots early in the firing, though all held together through smelting. – The flower pot smelter has been rebuilt at additional cost of $21 for 2 small containers of furnace cement and 1 bag of permiculite. The stronger of the two flower pots and the lid have been repaired with cement and interiors coated to a depth of 1 inch with a 1/1 mixture of cement and permiculite, which ought to provide sufficient insulation. The shop vac has been replaced with a lower power heating duct blower. 3 crucible alternatives will be tried: a smaller glazed ceramic flower pot, w/o drain hole, 5" long, capped 2" galvanized iron pipe, and a thicker walled stainless steel pot (Martha Stewart collection). Green clay additive for sand casting, ordered from a foundry supply company arrived on Friday (along with welding goggles and leather apron). Today we will construct cope & drag boxes for casting and light a small fire in the smelter to drive out any additional moisture. The boys have each carved small (3" x 2") objects out of foam - 2 robots, 1 blob - and on Wednesday we will attempt to cast these in aluminum using the "lost foam" process. Will have Andree standing by with camera to record and will post results....
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