Valuable Secrets concerning Arts and Trades:
or Approved Directions, from the best Artists, for the Various Methods...
Printed by Thomas Hubbard,
Norwich, 1795Chap. III. Secrets for the composition of Varnishes, &c.
XXXIX. A fine white varnish.
Take one pound of fine Venice turpentine, and as much of spirit of turpentine. Put this in a glass-matrass, larger, at least by a third, than is wanted to contain the matter. Stop this matrass with another smaller matrass, the neck of which is to enter into that of the former. Have care to lute well both necks together with paste and paper; and, when the luting has acquired a perfect dryness, set the first matrass on a sand bath, then set the varnish a-boiling, for near an hour, after which take it off from the fire, and let it cool. When cold, bottle and stop it for use.
Note. Turpentine, well purified from all its greasy parts, is the best, and fittest, to make the varnish for sashes.
XL. A curious and easy varnish, to engrave, with aquafortis.
Lay on a copperplate, as smooth and equal a coat as you can, of lintseed oil. Set the plate on a chaffing-dish, in which there is a gentle beat of half consumed charcoal, that the oil may congeal and dry itself gently on. When you find it has acquired the considence of a varnish, then you may draw with a steel point in order to etch your copper, and put on the aquafortis afterwards.
XLI. A varnish to prevent the rays of the sun from passing throng the panes of window-glasses.
Pound gum adragant into powder; and put it to dissolve, for twenty-four hours, in whites of eggs well beaten. Lay a coat of this on the panes of your windows, with a soft brush, and let it dry.
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