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.
XX. A varnish which dries in two hours time.
Melt four ounces of yellow amber, in a new earthen pan, over kindled coals. Take care, in that operation, that the fire should but just reach, and touch, the bottom of the pan, and none should rise along the sides. Never cease to stir, from the moment it is melted, with a deal stick, and add, directly, one ounce of sealing-wax. As soon as this is also melted, add again one spoonful, or half an ounce, of lintseed oil, previously thickened with a little gold litherage; then take it off from the fire, and cease not to stir as before. When the matter begins to be a little cold s then is the time of adding what quantity of turpentine oil you may find necessary to make a true varnish of it.
XXI. A varnish for copperplate prints.
Prepare water with some isinglass. Lay, with a very soft brush, a coat of this on the print. Next to this, lay another of the following varnish. True French spilit of wine, half-a-pound; gum-elemi, two drachms; and sandarak, three.
XXII. An admirable varnish.
Take white mastich and lintseed oils, what quantity you please; a little turpentine, pounded glass, burnt verdigrise, and pounded amber. Boil, and melt, all together in a new earthen pot. When done, you will find it to be an admirable sort of varnish.
XXIII. A varnish fit to lay on all sorts of colours.
Take one ounce of white amber; half, an onuce of spirit of turpentine; four ounces of rectified spirit of wine (the true French sort); one drachm of mastich, and as much of juniper gum. Put all together to infuse for eight days. Evaporate two parts of it over a gentle fire. What remains is a varnish fit for laying on all sorts of colours, and which will hurt, spoil, or damage none.
XXIV. A varnish known under the appellation if Beaume-blanc, or, white-balm.
Take spirit of wine, four ounces; gum-lac, half an ounce; sandarak, two drachms; mastich, one. Pulverise the ingredients, and put them, with the spirit of wine, in a square bottle large enough to be but half full after the whole is in it. Dissolve this over a slow fire, and take care the bottle should be well stopped first with a cork, and besides with wax and leather.
XXV. A varnish to be used on plaister, and any other sort of materials.
To the varnish of copal and spirit of wine, only add some calcined talk.
XXVI. An excellent varnish, in which may be put, and diluted, whatever colour you like. - It suits, equally well, goldsmiths and limners.
Take aspic and turpentine oils, of each one ounce; clean picked sandarak pulverised, four drachms; gum copal, two. The whole being well pulverised, put it along with your oils in a matrass, withk the addition of half a pound of spirit of wine; and set it in a balneo mariæ. When the matter is dissolved, strain and keep it for use, in a glass bottle well stopped.
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