Definition

• Sawdust.  A medium for drying in certain metal finishing functions, as in blanching. The best sawdust for drying comes from beechwood. But walnut shells or cob meal (also called maize cellulose–it comes from corn cobs) may be substituted for sawdust in drying operations. As with any drying process it is speeded up if the sawdust is heated.
  Sawdust is also a medium for certain metal coloring techniques, often of variegated or stippled effect. For metal coloring, hardwood sawdust (kind not too important, but here again, beechwood or boxwood is best) is moistened with the coloring solution and packed around the medallic object to be colored, allowing it to remain undisturbed for a period of time (several weeks). Moisture from the sawdust transfers to the metal surface adjacent to each grain or chip of sawdust. Two or more coloring solutions can thus be applied to the surface for a continuous period of time, each solution resulting in a different color, effecting the variegated appearance. Of course, finer grain sawdust will have tinier spots of color; larger chips will result in larger blotches of color.

  excerpted with permission from

  An Encyclopedia of Coin and Medal Technology

  For Artists, Makers, Collectors and Curators

  COMPILED AND WRITTEN BY D. WAYNE JOHNSON

  Roger W. Burdette, Editor

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