To Restore Burnt Steel. — Mix 4 ounces of sal ammoniac, 1 ounces of borax, 1 ounces of prussiate of pot ash, 1 ounce of blue clay, 12 ounces of rosin, 2 ounces of water, and 2 ounces of alcohol, and simmer with gentle heat until all liquid is evaporated. Sprinkle the resulting powder on the steel when hot, and work by hammer ing. Repeat as often as necessary.
To Protect Iron and Steel from Rust. — Substances recommended for protecting iron and steel from rust' are various varnishes of wax, rosin, India rubber, and asphaltum, and vari ous fixed nondrying oils or animal fats, black lead or graphite, and paints containing white lead, zinc white, etc.
Polished Iron or Steel. — To keep polished surfaces free from rust, ap ply a mixture of equal parts of copal varnish, sweet oil, and turpentine.
Or coat small articles, as knife blades, lancets, and the like, with col lodion dissolved in alcohol.
Or warm the articles until hot enough to scorch, and apply clean white wax. Continue the heat until the wax soaks into the metal. Let cool and polish with felt or velveteen.
Or melt a little common rosin with equal parts of cold linseed oil and spirits of turpentine, and apply as a varnish.
Or melt 1 ounce of pure India rub ber in 16 ounces of turpentine; add 8 ounces of boiled linseed oil. Mix and bring to a boil. Apply with a brush. Remove, when required, with turpen tine.
Or apply wax dissolved in benzine. Or apply black lead mixed with olive oil.
Rust-proof Paint for Steel and Iron.—Mix 20 pounds of white lead, 7 pounds of crude linseed oil, pounds of boiled linseed oil, and 1 pound of spirits of turpentine. First rub down the work with stiff wire or bristle brushes to remove rust, and fill all openings, inequalities, etc., with red or white lead mixed with cold lin seed oil to the consistency of putty. Apply two to four coats. Mix the last coat with a little glue size, and be fore it dries, dust with fine dry sand.
Or mix 4 parts of powdered brick dust sifted through cheese cloth with 1 part of litharge and rub up the whole, or grind to a thick paste with linseed oil. Dilute, as required, with turpentine. Rub the iron free from rust with stiff wire or bristle brushes, and apply two coats of the above with a brush. This will resist salt water.
Or apply two or three thin coats of boiled linseed oil with or without col oring matter. Let each coat dry thor oughly before the next one is applied.
Or mix 81 pounds of sulphur, 2i pounds of caustic potash, and 8 ounces of copper filings.
Or melt together with gentle heat 5 pounds of tallow and 1 pound of turpentine. Melt separately 18 ounces
of sulphur, 5i ounces of caustic pot ash, and 1 ounce of copper filings. Mix the two while hot and apply as a paint to iron or steel. This mixture resists salt water and all atmospheric conditions.
Iron and Zinc.—The contact of zinc with iron and steel is favorable to their preservation, as it causes a gal vanic current to be set up which at tacks the zinc instead of the iron. The zinc will be slightly affected, and the iron not at all. The contact of lead and some other metals, on the con trary, sets up a galvanic current which attacks the iron. This is one of the elements of value in galvaniz ing iron by covering it with a coat of zinc, and for the same reason zinc white should be substituted for white lead in the composition of paints for ironwork, and zinc or brimstone should be used for setting iron posts and the like in stone foundations, or for solders on ironwork exposed to the weather.
Iron for Electrotypes.—To coat the surface of an electrotype with iron, prepare a bath by dissolving 8 ounces of sal ammoniac in 2 quarts of rain water. Add 1 pound of neutral ace tate of iron, and boil 2 hours in an iron kettle, adding water up to 2 quarts as it evaporates. Cool, filter through cheese cloth, put in glass jars or bottles, and cork tightly for use.
Connect with the positive pole of a battery of three or more cells a per fectly clean plate of iron of the same size as the electrotype. Connect the electrotype with the opposite pole of the battery, and fill the tank with the above solution, filtering it through cheese cloth. When the coating is satisfactory, rinse the plate in soft water containing a little borax, dry thoroughly, and with a brush apply a thin coating of boiled linseed oil. This process makes a plate almost as durable as a steel plate, having a coat of pure metallic iron and show ing its characteristic white metallic luster.
To Polish Iron. — To give iron as bright a polish as steel, prepare a bath by pulverizing and dissolving in 1 quart of hot water 1 ounce of blue vitriol, 1 ounce of borax, 1 ounce of prussiate of potash, 1 ounce of char coal, and pint of salt. Bring to a boil, stir in 1 gallon of linseed oil, mix thoroughly, and cool for use.
Heat iron or steel to the proper temperature for tempering, and quench in this solution. The object is to case harden iron with a bright polish.
Copper Color for Iron.—Dissolve 1 ounce of copper filings in a mixture of 1 ounce of nitric acid and 2 ounces of muriatic acid. Apply by means of a brush or swab.