walling wax

walling wax (uncountable)

1. A mixture of wax and tallow used by etchers and engravers to make a bank, or wall, round the edge of a plate, so as to form a trough for holding the acid used in etching, etc.
   • 1811, John Hassell, Calcographia:

     walling wax, to put round the plate, […] is made of bees wax, dissolved in a pipkin with horse turpentine

• “walling”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.