Sealing-wax. Before the composition of ordinary sealing-wax was known in Europe coloured beeswax was used for sealing letters and for attaching the impressions of seals to documents. Sealing-wax with Lac (q.v.) as the principal ingredient was probably first made in India or China, since it is only in these and neighbouring countries that the lac insect is found. Beckmann states that the use of sealing-wax made of lac was apparently very common among the Portuguese about the middle of the 16th century. The best red sealing-wax consists of shellac from 5 to 6 parts, Venice turpentine 3 to 4 parts, vermilion 3 to 4 parts, to which is frequently added part of magnesia, chalk, or gypsum, or a mixture of some of these. Inferior but still fairly good kinds have a considerably less amount of shellac and vermilion in their composition. Parcel-wax is made of shellac 3 parts, common resin 7 parts, turpentine parts, chalk and gypsum together parts, and either vermilion 3 parts, or red-lead 6 parts. Bottle-wax is often made of pine-resin, turpentine, chalk, and some colouring matter; but it is very brittle unless about 10 per cent. of shellac is added.
In making sealing-wax the shellac and other materials are carefully melted in metal pans, and quickly stirred to prevent heavy colouring matter such as vermilion from falling to the bottom. The melted sealing-wax is then poured into metal moulds to form it into sticks, which are removed when cold. By one method the sticks are polished by spreading them on a table and passing a red-hot bar of iron over them. Another way is to hold them into a stove, and in either case till the surface just begins to melt. Sealing-wax is made in various colours, the finer qualities, however, being most largely in red. White, until recently, was chiefly coloured by subnitrate of bismuth, but a special kind of white-lead is now employed. Black is made by the addition of lampblack or vine-black to the other materials. For brown, umber is added; for blue, artificial ultramarine or Berlin blue; for green, Berlin blue and chrome-yellow; for yellow, either chrome-yellow (which will not stand a high heat) or ochre. For common wax some cheaper colouring materials are used, such as baryta for a white. Aniline colours have been tried for sealing-wax with some promise of success.