The Manufacture of Varnishes and Kindred Industries Volume 2 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...conclude that the fire is too violent. "I have succeeded in composing varnish with fat oil, in the same operation, by substituting drying oil in a state of ebullition for the water, and keeping it in that state by means of a mass of very hot iron, which served it as a supporter. The mixture of the liquefied matter is facilitated by means of a spatula, with a knee at the extremity, and the boiling oil of turpentine is afterwards added. The inconvenience of placing a volatile and highly inflammable oil under the apparatus may be readily conceived. "I shall always insist more on the separate liquefaction of copal than on the possibility of completing the mixture of it with a drying oil, to form a varnish of the fifth genus. This new means enables the artist to compose a very durable and nearly colourless varnish, superior to copal varnish composed with drying oil, as the composition of the latter requires processes which alter the essential qualities of the substances that form the basis of it. "For operations on a larger scale, the dimensions of the furnace may be changed; but in this case it will be proper to put the fireplace, properly so-called, on a kind of iron tripod, as represented at G, Fig. 26, in order that the workman may be more at his ease. I must, however, always insist on the advantage of employing not more than six ounces in one operation. "The valuable advantages resulting from this new method will be perceived when a trial has been made of the varnish composed with oil of turpentine and copal melted by it. Copal thus prepared has properties different from, and more extensive than, those communicated to it by the common method; and it has not that dark brown colour which it acquires by too high a temperature and too long e...