Annealing & Whirlaway B Roll
United States Mint [Multimedia] (2016)
Multi-Media SummaryThis b-roll shows the blanks arriving at the annealing furnace, where they will be heated to soften the metal. [NOTE: For most coins, annealing is done in a large furnace. However, because this process is difficult to capture on film, this video includes a shot of a 3-inch medal being annealed by a blowtorch. Because medals are made in lower quantities, it is possible to anneal them by hand.]
From the furnace, the blanks drop into a quench tank to reduce the temperature. Next, the blanks travel through a huge cylindrical tube called the "whirlaway." Suspended high above the ground, these tubes tilt at a 45-degree angle toward the washing and drying station. As the blanks travel up the whirlaway toward the washer, excess liquid is drained.
After leaving the whirlaway, blanks are placed in a washing machine. Similar to the washing machine process you might have in your home, the blanks go through a series of cycles that soak and shake the blanks in various chemicals. This is to remove any oxides, tarnish, discoloration or contamination that remains after annealing.