This is usually applied on smooth castings, two coats being given. When dry and hard, it may be rubbed with pumice and water, but is mostly smoothed down with emery cloths and oil. The following formula produces a light shade of steel color, but by increasing the percentage of lampblack, a medium or dark shade is> obtained. Must be ground fine on suitable mill:

30 lbs. slate flour (ground slate);

15 "

bolted American Paris white;

15 "

fine silica or pumice;

1/2 "

dry lampblack;

8 1/2 "

dry white lead;

8 1/2 "

barytes, floated;

20 "

black filler japan;

2 1/2 "

hard rubbing varnish;

100 lbs.