3278. To Blue Steel

3278.    To Blue Steel. The mode employed in blueing steel is merely to subject it to heat. The dark blue is produced at a temperature of 600°, the full blue at 500°, and the blue at 550°. The steel must be finely polished on its surface, and then exposed to a uniform degree of heat. Accordingly, there are three ways of coloring: first, by a flame producing no soot, as spirit of wine; secondly, by a hot plate of iron; and thirdly, by wood ashes. As a very regular degree of heat is necessary, wood ashes for fine work bear the preference. The work must be covered over with them, and carefully watched; when the color is sufficiently heightened, the work is perfect. This color is occasionally taken off with a very dilute muriatic acid.

3279. To Blue Small Steel Articles

3279.   To Blue Small Steel Articles. Make a box of sheet iron, fill it with sand, and subject it to a great heat. The articles to be blued must be finished and well polished. Immerse the articles in the sand, keeping watch of them until they are of the right color, when they should bo taken out, and immersed in oil.

3280. To Make Edge-Tools from Cast-Steel and Iron

3280. To Make Edge-Tools from Cast-Steel and Iron. This method consists in fixing a clean piece of wrought iron, brought to a welding heat, in the centre of a mould, and then pouring in melted steel, so as entirely to envelop the iron; and then forging the mass into the shape required.

3281. To Remove Scale from Steel

3281.    To Remove Scale from Steel.

Scale may be removed from steel articles by pickling in water with a little sulphuric acid in it, and when the scale is loosened, brushing with sand and a stiff brush.

3282. To Restore Burnt Cast-Steel

3282.    To Restore Burnt Cast-Steel. Take li pounds borax, 1/2 pound sal-ammoniac, 1/4 pound prussiate of potash, 1 ounce resin. Pound the above fine, add a gill each of water and alcohol. Put in an iron kettle, and boil until it becomes a paste. Do not boil too long, or it will become hard on cooling.

3283. To Anneal Steel

3283. To Anneal Steel. For a small quantity. Heat the steel to a cherry red in a charcoal fire, then bury it in sawdust, in an iron box, covering the sawdust with ashes. Let it stay until cold. For a larger quantity, and when it is required to be very soft, pack the steel with cast-iron (lathe or planer) chips in an iron box, as follows: Having at least i or 3/4 inch in depth of chips in the bottom of box, put in a layer of steel, then more chips to fill spaces between the steel, and also the 1/2 or 3/4 inch space between the sides of box and steel, then more steel; and, lastly, at least 1 inch in depth of chips, well rammed down on top of the steel. Heat to and keep at a red heat for from 2 to 4 hours. Do not disturb the box until cold.