FRENCH POLISH. This material is made by dissolving orange shellac in alcohol. It has a turbid orange-brown appear ance and dries in about ten minutes with a pale brownish colour. The turbidity is due to the presence of a proportion of wax in the shellac, which is insoluble in alcohol. When French polish is allowed to stand, this insoluble wax settles and it is therefore necessary for the polish to be shaken before use.
The ordinary process of manufacture is to place orange shellac and industrial methylated spirit in large wooden churns having a capacity from 1 oo-15o gal., which are allowed to revolve slowly for about 18 hours. The polish is then strained through coarse strainers into wooden or earthenware storage receptacles : tin or iron containers must not be used, since the action of the shellac on the metal would turn the polish black.
The proportion of orange shellac used varies from 2 to 3 lb. to 1 gal. of methylated spirit. Other resins such as gum benzoin, gum elemi, Venice turpentine, French rosin, sandarac, etc., are usually added to improve the elasticity and gloss of the polish.
French polish is applied by means of a rubber made with cotton wool wrapped in a clean white linen cloth. The cotton wool is soaked with the polish, covered with the linen cloth, and then passed quickly all over the work with smooth circular sweeping movements accompanied by a slight pressure. This is repeated a very large number of times until the desired highly polished finish is obtained. French polishing is a highly skilled trade and the best results can only be obtained by experienced craftsmen. (See