a box that is lined with moist material for keeping clay in a plastic state.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for damp box
Historical Examples of damp box
All work to be stuck up or modelled on should be kept in the damp-box until quite finished and then dried very gradually.
Various other expedients for drying cupboards, damp-box, etc., will suggest themselves as the course develops.