SPIRIT OR LAC VARNISHES These differ from fixed-oil varnish es in being true solutions of various resins, chiefly anime, mastic, shellac, and sandarac, in spirituous solvents, usually alcohol and wood spirit, or acetone, benzine, etc.
Sandarac is used to impart hard ness, mastic to give a gloss. Venetian turpentine is frequently added to san darac, or a little concentrated am monia is often added to overcome the tendency of varnish to chill or crack and give a rough surface. Venetian turpentine is used with sandarac to prevent excessive brittleness.
To make spirit varnishes, first pul verize the resins and mix them with sand or broken glass to prevent their forming into lumps. Put them in a double boiler, cover with the spirit, which should be not less than 95 per cent pure, and dissolve with gentle heat. Afterwards filter, first through silk, then through filter paper.
Shellac Varnishes.—Shellac will be more soluble if powdered and ex posed to the air as long as possible before using. To make cheap shel lac, dissolve 1 ounce of borax in 8 ounces of boiling water. Add 5 ounces of pulverized shellac, stir, and boil until dissolved. If too thin, continue to boil until sufficient water has evap orated, or if too thick, thin with boil ing water. This solution is equal to spirit varnishes for many purposes, and is much cheaper. When dry, weather has no effect upon it. Hence it is useful to dissolve water colors for calcimining and for other pur poses.
Or India ink rubbed up in this solution may be used where an aeid proof labeling ink is required. It is not affected by the fumes of acids.
Or put in a glass fruit jar 8 ounces of water, 3 ounces of white shellac, and 1 ounce of sal' ammoniac, and let stand over night. Place the fruit jar in a saucepan containing hot water, and boil, stirring constantly until the shellac is dissolved.
Or boil in an earthen vessel.
This solution may be used as a sub stitute for spirit varnish, is much cheaper, and has the advantage of be ing waterproof. Diluted with 10 or 12 parts of water and applied by means of a brush, it may be used for waterproofing cloth or making oil cloth. It may also be used for stain
ing and waterproofing wood, as a stain paint or a varnish, according to consistency, and may be mixed with any water-color or oil pigments to produce any color that may be de sired.
The above are not true spirit var nishes, but may be treated most con veniently in this place.
Or dissolve 10 ounces of white shel lac in 1 quart of 95 per cent alcohol. This may be done without heat by pouring the alcohol over the shellac and letting it stand in a warm place until dissolved. Keep in a covered fruit jar or corked bottle to prevent evaporation. This is a good trans parent varnish for furniture, wood work, tools, and most other purposes. It dries rapidly. It is especially use ful to coat woodwork that is exposed to the weather, as farming tools and other utensils that are frequently used or left out of doors. It is a very con venient and serviceable all-round var nish.
Or color the above by the addition of lampblack or asphaltum. This gives a glossy black varnish.
Or, to give a thicker coat of var nish, take 1 quart of 95 per cent al cohol, and add all the gum shellac it will cut. Strain out the excess through silk and filter paper. Add 2 ounces of Venetian turpentine. This gives a transparent gloss.
Or color with aniline dyes as de sired.
Or, to make a hard shellac varnish for special purposes, as gunstocks and the like, dissolve 10 ounces of shellac, 1 ounce of sandarac, and I dram of Venetian turpentine in 1 gallon of 95 per cent alcohol. Put in a glass fruit jar or earthenware vessel, cover tight ly, and let stand in a warm place until dissolved. Apply two or three coats, and finish, if desired; with one or two coats of still harder varnish, prepared as follows: Dissolve 1 ounce of shellac, k ounce of sandarac, and ounce of Venetian turpentine in 2 quarts of alcohol. This gives a high polish and requires less rubbing.