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DIY Metal Casting Reverb

A reverberatory furnace, or "reverb," is an enclosure for smelting metal using reflected and radiated, rather than direct, heat. In contrast to a blast furnace where fuel and metal ore are heated together, the heat in a reverb passes over the surface of the solid metal or metal ore and melts it. Small-scale do-it-yourself reverbs require a chamber with a depression in the bottom over which heat is directed. This setup can melt brass or aluminum within one hour.

Things You'll Need

Two refractory cast bricks approx 12 to 14 inches square
Chisel
Hammer
Plumber̵7;s propane burner
Goggles
Leather welding gloves
Tongs
Wooden box
Green sand
Molding object such as wooden block or metal cast

Instructions

- 1
  Use the hammer and chisel to carve out a bowl in both bricks. Ensure that the bowl is no deeper than one-half of the thickness of the bricks. Leave a flat margin of 3 to 4 inches around the circumference of the carved bowl. When the bricks are placed together to form the furnace, one bowl is the crucible for metal melting and the second bowl acts as a cupola for heat circulation.
- 2
  Carve two gouges in the flat surfaces on opposite sides of both bricks running between the edge of the brick and the bowl. These form the entry point for the propane burner and a flue gas escape. Fit the bricks together to gauge the sizes of the holes formed by the gouges. Insert the propane burner nozzle to ensure there is a snug fit.
- 3
  Place metal scraps for melting into the bowl area of one of the bricks. Place the second brick over the first creating an internal chamber, an entry point for the propane burner and a flue gas escape. Ignite the propane burner and leave to burn for one hour. Stand at least 3 feet away from the furnace.
- 4
  Place the green sand ̵1; a molding mixture of silica sand, clay and moisture - into the wooden box. Compact the sand into the box and compress it around the box edges. Press the molding object into the sand to create the mold shape desired. Leave the green sand to dry until it hardens. Remove the molding object.
- 5
  Switch off the propane burner after one hour of burning. Use the tongs to remove the top refractory brick. Use the tongs to pick up the lower refractory brick containing the molten metal. Pour the molten metal into the mold using the firebrick gouge as a conduit. Allow the molten metal to cool and solidify.

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