This should be almost similar to the Rivet Head or Butt End composition for steel ships, and applied when the sheets are joined.

Must be in the form or consistency of medium stiff putty and the following makes the best composition, which should be run through a water cooled mill with large eye; taking good care not to overheat the material:

60 pounds basic carbonate of lead, dry;

10 "

red lead;

10 "

fine bolted whiting;

15 "

rubbing varnish of high grade;

5 "

raw linseed oil;

100 pounds

A thin coating of this compound is applied, when the sheets are rivetted together, the excess being pressed out during the operation, and collected for future use.