PROCESS TO MAKE VARNISHES. 



27 



grains of fine dragon's blood, and mak ean 

 extract with twenty ounces of alcohol, in 

 a gentle heat. Oil varnishes are commonly 

 mixed immediately with the colors; but 

 lac or lacquer varnishes are laid on by 

 themselves upon a burnished colored 

 ground. When they are intended to be 

 laid upon naked wood, a ground should 

 be first given them of strong size, either 

 alone or with some earthy color, mixed 

 up with it by levigation. 



The gold lacquer is simply rubbed over 

 brass, tin, or silver, to give them a gold 

 color. Before a resin is dissolved in a fixed 

 oil it is necessary to render the oil dry- 

 ing. For this purpose, the oil is boiled 

 with metalic oxides, in which operation 

 the mucilage of the oil combines with the 

 metal while the oil itself unites with the 

 oxygen of the oxide. 



To accelerate the drying of this varnish 

 it is necessary to add oil of turpentine. 

 The essential varnishes consist of a solu- 

 tion of resin in oil of turpentine. The 

 varnish being applied the essential oil 

 flies ofi" and leaves the resin, this is used 

 only for paintings. When resins are dis- 

 solved in alcohol the varnish dries very 

 speedily and is subject to crack; but this 

 fault is corrected by adding a small quan- 

 tity of turpentine to the mixture, which 

 renders it brighter, and less brittle whea 

 dry. The colored resins or gums, such 

 as gamboge, dragon's blood, &c. are used 

 to color varnishes. To give lustre to the 

 varnish after it is laid on, it is rubbed 

 with pounded pummice stone and water, 

 which being dried with a cloth^ the work 

 is afterwards rubbed with an oiled rag 

 and tripoli. The surface is last of all clean- 

 ed with soft linen cloths, cleared of all 

 greasiness with powder of starch, and 

 rubbed bright with the palm of the hand. 

 The following receipt for a good spirit var- 

 nish is given by Tingry : Take strong alco- 

 hol thirty-two parts; pure mastich, four; 

 sandarach, three; clear Venice turpentine, 

 three; coarsely ground glass, four; reduce 

 the mastich and the sandarach to fine 

 powder; introduce them with the glass 

 and spirit, into a matrass, which is to be 

 placed in hot water, for one or two hours 

 taking care to stir up the materials from 

 time to time with a glass spatula; then 



pour in the turpentine, and keep the ves- 

 sel tor half an hour longer in the water. 

 Next day decant off" the liquor, and filter 

 it through cotton. It will be perfectly 

 limpid. This varnish isusualy applied to 

 objects of the toilet, as work boxes, card 

 cases, «§'C. Essence varnish, by the same. 

 Take mastich in powder twelve parts; pure 

 turpentine one and a half; camphor in bits, 

 one half; crystal glass ground, five; recti- 

 fied oil of turpentine, thirty-six. Put the 

 mastich, camphor, glass and oil into a 

 matrass, and dissolve as above described. 

 This varnish is applied to paintings. Fat 

 varnish. Take copal, sixteen parts, lin- 

 seed, or poppy oil, made drying with 

 litharge, eight; oil of turpentine, sixteen, 

 melt the copal in a matrass by exposing 

 it to a moderate heat; pour then upon it 

 the boiling oil; stir the mixture and when 

 the temperature is about 200° Fahr. add 

 the oil of turpentine heated; strain the 

 whole through a linen cloth and keep 

 the varnish in a wide mouth bottle. It be- 

 comes very clear in a little while, and is 

 almost colorless when well made. Copal 

 varnish is applied on coaches, also gener- 

 ally on polished iron, brass, copper, and 

 wood — varnish, among medalists, is the . 

 term used to signify those hues which an- 

 tique medals have acquired by lying in 

 the earth. The beauty which nature alone 

 is able to impart to medals^ and which 

 art has never yet attained the power 

 of counterfeiting, enhances their value. 



The colors acquired by certain metals, 

 from having lain a long while in the 

 ground, are various, and some of them 

 exquisitely beautiful. The blue nearly 

 rivals that of turquoise, others have an in- 

 imitable Vermillion color ; others again, 

 a polished shining brown. But that most 

 usually found is a delicate green, which 

 hangs to the finest strokes without effac- 

 ing them. No metal except brass is sus- 

 ceptible of this. The green rust which 

 gathers on silver, always spoils it, and 

 must be removed with vinegar or lemon 

 juice. Falsifiers of medals have a varnish 

 which they use on their counterfeits, to 

 give them the appearance of being an- 

 tique; but there are means of discovering 

 these deceptions. — (See Numismatics) 

 Encyclopedia Americana. 



