The Collaborative International Dictionary of English v.0.48:

Coppering \Cop"per*ing\, n.
   1. The act of covering with copper.
      [1913 Webster]

   2. An envelope or covering of copper.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Copper \Cop"per\, v. t. [imp. & p. p. Coppered; p. pr. & vb.
   n. Coppering.]
   To cover or coat with copper; to sheathe with sheets of
   copper; as, to copper a ship.
   [1913 Webster]