smelting vs solder

smelting

noun
  • The process of melting or fusion, especially to extract a metal from its ore. 

solder

noun
  • Any of various easily-melted alloys, commonly of tin and lead, that are used to mend, coat, or join metal objects, usually small. 

  • Figuratively, circumstances or emotions that strongly bond things or persons together in analogy to solder that joins metals. 

verb
  • to join things as if with solder. 

  • to join items together, or to coat them with solder 

How often have the words smelting and solder occurred in a corpus of books? (source: Google Ngram Viewer )