Varnishes

Varnishes are made from some hard gum, such as copal, rosin, etc., cut with turpentine, alcohol, or other suitable solvent. Varnishes are prepared for commercial purposes and are put up in convenient forms ranging all the way from one dollar to ten dollars per gallon.

1 The colors used in preparing these stains can be bought ground in oil and put up in pound cans. Use enough color to give the desired shade. By combining colors different colors and shades may be obtained.

2 Umber is a mineral pigment formerly obtained from Umbria in Italy, from which its name is derived. The commercial supply now comes largely from the island of Cyprus. Small quantities are also found in Pennsylvania. When raw umber is highly heated, it gives a richer and deeper brown known as burnt umber.

3 Sienna is an ocherous earth which comes from the province of Sienna in Italy, from which its name is derived. In its natural state it is known as raw Sienna. When highly heated a richer red is obtained, known as burnt Sienna.

Shellacs

Shellac is used extensively in manual trainingwork. It is made from lac, or gum-lac, a resinous substance which comes from the branches of several trees, the most common of which are the Ficus religiosa (the religious tree of the Hindus), the Rhamnus jujuba, and the Croton lacciferum (behar-tree). These trees grow in Siam, Assam, Pegu, Bengal, and Malabar. An insect (the female insect of Coccus lacca) punctures the bark of these trees for the purpose of depositing her eggs; the resinous substance oozes from the tree and hardens on the twigs. These twigs are broken off by the natives and dried in the sun. The dried twigs are called stick-lac. After the twigs have become thoroughly dry they are pounded to break the resinous substance from the twigs. The resinous substance after the twigs are removed is known as seed-lac. When seed-lac is melted, collected, and cooled, it is called lump-lac. Seed-lac is put into bags made of cotton and hung over a slow fire. When the resinous substance melts, the bag is twisted and the clean substance is allowed to flow over planks made of fig wood which are hard and smooth. The resinous substance cools on these planks, forming thin layers or scales known as shell-lac, or shellac. By passing chlorine, one of the most powerful of bleaching agents, through shellac the coloring matter is taken out, giving a substance known as bleached shellac, or white shellac.

How To Prepare Shellacs

Bleached shellac should be put in alcohol as soon as possible after it is prepared. When exposed to air for a few days, it oxidizes and becomes insoluble.

Fillers

Many woods which have an open grain, such as oak, ash, etc., require a filler. A filler, as its name suggests, is a substance which is used in filling the pores of wood. They are made from such material as whiting, plaster of Paris, starch, etc., which are mixed with oil or turpentine. The filler is applied to the wood and when dry is rubbed down with fine sandpaper. This gives a smooth surface for the paints and varnishes.