Evening Republican, Volume 21, Number 61, Rensselaer, Jasper County, 14 March 1917 — Blackening Metals. [ARTICLE]

Blackening Metals.

The ruthless black surface given metals by a patented British process depends upon heating in carbonaceous material containing phosphorus, and then quenching in carbonaceous liquid. Cleaning of the articles IS 'first effected by pickling or by a blast of shot or sand. Articles designed for 'ordinary conditions of corrosion may be given a thin coating of zinc, which is applied by placing the cleaned obdegrees or 875 degrees Centigrade, in a suitable furnace for about three huiirs. A drunvor furnace electrically headed is very efficient. The zinc-coat-ed metal is next placed in a hot mixture of-45 quarts of charred bone dust to one quart of liquid coal-tar, and is heated an hour and a half to about {l6O degrees. Removed to an oven, the articles are now baked about five- minutes at 500 degrees. They are finally taken out, and quenched in a bath of boiled linseed oil.