Or insert a rivet of copper or Swed ish iron and hammer it gently, with or without the addition of suitable sol der, until it is tight.
Or use for this purpose one of the brass brads sold by stationers. In sert the prongs and open and hammer them down tight, adding, if con venient, a little soft solder.
To Temper Steel.—Heat the steel to a cherry red in a clear smith's fire. Cover it with common salt and throw salt into the fire to purify it. Work the steel in this condition and subject it to this treatment until it is wrought nearly to its finished form. Then, in stead of salt, mix 1 part each by weight of common salt, sulphate of copper, sal ammoniac, and sal soda with part of saltpeter. Pulverize and mix these ingredients thoroughly. Alternately heat the steel and treat it with this mixture, and hammer it until it is refined and wrought into its finished form. Return it to the fire, heat it to a cherry red, and plunge it into a bath as follows: In 1 gallon of rain water dissolve ounces of alum, 1 ounces of sal soda, 1 ounces of sulphate of copper, 1 ounce of saltpeter, and 6 ounces of salt. The right to use the above proc ess was purchased by the United States Government for $10,000. It is the celebrated patent of Garman and Siegfried.
To Temper Steel Springs.—To tem per cast-steel springs for traps and similar purposes, heat them in the dark until you can just see them turn ing red. Then quench them in luke warm water. The object of working in the dark is that the redness can be seen at a lower degree of heat. Low heat and warm water impart the de sired temper.
To Blue Steel.—Polish the surface of the steel and cleanse it thoroughly with lime or caustic potash. Place the articles in charcoal ashes or wood ashes in a suitable receptacle, and heat them slowly until the required color is produced.
Or cover the iron plate with slaked lime and lay the articles on it.
Or simply hold the articles in a clear flame, as that of burning alco hol, or over a smith's forge, protect ing them from soot by a steel or an iron plate, and remove from the heat when the required color is secured.
Or, for a second blue more perma nent than the first, let the steel pass from a blue to a white heat, remove from the fire, and cool, afterwards re heating to blueness. Let the steel cool in both cases without quenching.
To Stain Steel Blue.—Put 1 ounce of butter of antimony in a strong earthenware or glass vessel, and add slowly a mixture of 1 ounce of nitric acid with 2 ounces of muriatic acid. This process produces vigorous heat. Apply this mixture with a piece of felt to polished iron or steel, and rub with the bark of a green oak tree un til the color is satisfactory.
To Stain Steel Gray.—Mix 2 ounces of butter of antimony with 1 ounce of sulphuric acid, and add 5 drops of gallic acid. Apply with a piece of felt to polished steel.
To Take Off the Blue.—Mix equal parts of muriatic acid and elixir of vitriol, immerse the articles in the mixture until the color changes, rinse, and dry.
To Melt Steel. — To melt iron or steel as easily as lead, heat the metal to redness and touch it with a cake of brimstone. The metal will melt and drop like water. Thus holes of any desired size can be readily melted out of iron or steel by applying sul phur, which softens the metal at the point of application.
TO Remove Scale from Steel.—Im merse the metal in water slightly acid ulated with sulphuric acid to loosen the scale, then scour with sand soap, using a stiff wire or fiber brush.
To Anneal Steel.—Heat the metal in a coke fire on a smith's hearth. Cover with sawdust, and then with ashes, and let stand until cool.
Or in any suitable iron receptacle pack the articles in chips of cast iron from a lathe or planer. The articles must be protected by a layer of an inch or more of the chips all around the sides, top, and bottom, which must also be tamped down. Heat the whole, and keep at a red heat for two hours or more. Remove from the fire and let stand until cold. This process gives a very soft metal.
To Toughen Steel.—Melt together 2 parts of rosin, 2 parts of tar, and 1 part of black pitch, and plunge the articles in this when hot.