This section is from the book "The Tinman's Manual And Builder's And Mechanic's Handbook", by Isaac Ridler Butt. Also available from Amazon: The Tinman's Manual And Builder's And Mechanic's Handbook.
1. White wax, two ounces; black and Burgundy pitch, of each one-half ounce; melt together, add by degrees powdered asphaltum two ounces, and boil till a drop taken out on a plate will break when cold by being bent double two or three times between the fingers; it must then be poured into warm water and made into small balls for use. 2. (Hard Varnish.) Linseed oil and mastic, of each four ounces; melt together. 3. (Soft Varnish.) Soft linseed oil, four ounces; gum benzoin and white wax, of each one-half ounce; boil to two-thirds.
Digest gum sandarach twenty parts, gum mastic eight parts, camphor one part, with alcohol forty-eight parts. The map or engraving must previously receive one or two coats of gelatine.
For fixing engravings or lithographs upon wood, a varnish called mordant is used in France, which differs from others chiefly in containing more Venice turpentine, to make it sticky; it consists of sandarach, 250 parts; mastic in tears, 64; rosin, 125; Venice turpentine, 250; alcohol, 1000 parts by measure.
1. Dextrine 2 parts, alcohol 1 part, water 6 parts. 2. Varnish for drawings and lithographs: dextrine 2 parts, alcohol ½ part, water 2 parts. These should be prepared previously with two or three coats of thin starch or rice boiled and strained through a cloth.
Digest at a slow heat gum sandarach two parts, gum mastic four parts, balsam copaiva two parts, white turpentine three parts, with spirits of turpentine four parts, alcohol (95 per cent) 50-56 parts.
Honey, 1 pint; the whites of two dozen fresh hen's eggs; 1 ounce of good clean isinglass, 20 grains of hydrate of potassium, ½ ounce of chloride of sodium; mix together over a gentle heat of 80 or 90 degrees Fah.; be careful not to let the mixture remain long enough to coagulate the albumen of the eggs; stir the mixture thoroughly, then bottle. It is to be applied as follows: one table spoonful of the varnish added to half a table spoonful of good oil of turpentine, then spread on the picture as soon as mixed.