It is not economical for painters to make these for themselves, as they may be purchased both cheaper and in most cases better than they could make them. At the same time it is well to know how to make these important compounds, for it may so occur that the materials may be obtained where the varnish itself could not, or other circumstances may render it desirable that the varnish should be made at home, a few receipts for the purpose are, therefore, given.
Take of oil of turpentine 1 pound, beeswax 2 ounces, colophony 1 drachm, Dammar resin 1 pound, spirits of turpentine 2 pounds, camphor 200 grains. Allow the mixture to stand for twenty-four hours, and the portion poured off is fit for immediate use.
Dissolve 1 1/2 pounds of shellac in 1 gallon of naphtha, and it will be ready for use as soon as the dissolution is complete. Dissolve 12 ounces of shellac and 3 ounces of copal, or an equivalent of Copal Varnish, in 1 gallon of naphtha. Dissolve 2 ounces mastic, 1 1/2 pounds shellac, 4 ounces seed lac, 4 ounces sandarach, or 1 gallon of rectified spirits of wine, benzoin, and dragon's blood, tumeric and other coloring matters may be added as required.
Gum sandarach 2 ounces, shellac 1 ounce, gum benjamin 1/2 ounce, Venice turpentine 1 ounce, spirits of wine 1 pint. Color red with dragon's blood, or yellow with saffron, place the vessel containing these ingredients in a warm spot, until the gum has dissolved, then strain for use.
Dissolve 6 ounces of white wax in 1 pint of oil of turpentine by gentle heat, or white wax 6 parts, petroleum 48. To be applied to the work whilst warm; allowed to cool, and then to be polished by rubbing with a coarse cloth.
Varnish which resists boiling water. Linseed oil 1 1/2 pounds, amber 1 pound, pulverized litharge 5 ounces, powder white lead 5 ounces, minium 5 ounces. Boil the linseed oil in an untinned copper vessel, and suspend in it the litharge and minium in a small bag, which must not touch the bottom of the vessel. Continue the ebullition until the oil has acquired a deep brown color, then take out the bag, and put in a clove of garlic, this is to be repeated seven or eight times, the boiling being continued. Before amber is added to the oil, it is to be mixed with 2 ounces of linseed oil, and melted over a fire that is well kept up. When the mass is fluid, it is to' be poured into the linseed oil, this mixture is to be boiled and stirred continually for two or three minutes. Afterwards, filter the mixture, and preserve it in a bottle well corked up. When this varnish is used the wood must be previously well polished, and covered with a thin coat of soot and spirits of turpentine. When this coat is dry, some of the varnish may be applied with a sponge, taking care that it is equally distributed on every part. This operation is to be repeated four times, being always careful that each coat be well dried before another is put over it.
After the last coat of varnish the wood must be dried in an oven, and afterwards polished.
One pint of spirits of turpentine, 10 ounces clear resin pounded, put it in a tin can on a stove, and let it boil for half an hour. When the resin is dissolved, and the mixture has cooled, it will be ready for use.
In three pints of rectified spirit dissolve 1 pound of gum sandaraeh, and add 6 ounces of turpentine. Dissolve 4 ounces gum mastic, 1/2 pound gum juniper, in 4 pints rectified spirit, add to the mixture 1 ounce of turpentine. Mastic in tears 2 ounces, sandaraeh 8 ounces, gum elemi 1 ounce, Chio turpentine 4 ounces, rectified spirit 1 quart.
Immerse 10 ounces of the clearest gum mastic in 1 pint of turpentine, place the vessel containing the mixture in a sand bath until the mastic is all dissolved, then strain it through a fine sieve, and it will be ready for use, if too thick, it may be diluted by the addition of spirits of turpentine.
Dissolve in about 2 pounds of tar oil, 1/2 pound of asphaltum and a like quantity of pounded resin, mix hot in an iron kettle, care being taken to prevent any contact with the flames. When cold the varnish is ready for use. This varnish is for outdoor work and iron-work.
Place 3 pounds of powdered resin in a tin can, and add 2 1/2 pints of spirits of turpentine, shake well, and allow the mixture to stand for a day or two, shaking it occasionally. Then add 5 quarts of boiled oil, shake the whole, and allow it to stand in a warm room until clear. This clear portion is then to be poured off for use, and may be reduced in consistency by the addition of turpentine. This varnish is intended for protecting surfaces against the effects of exposure to the atmosphere, and has been used with great advantage for coating wood and iron-work.