Zinc Paint, ordinarily so called, is made with oxide of zinc (see p. 409), instead of white lead, as a basis.

Characteristics And Uses

Zinc white does not combine with oil so readily as white lead. Its covering properties are therefore inferior, and it takes a long time to harden.

It is acted upon by the carbonic acid in rain water, which dissolves the oxide, and it therefore weathers badly.

The acids contained in unseasoned wood have a great effect upon it.1

1 Dent.

Zinc paint may be used without fear of painters' paralysis, and as it has no smell, places in which it has been used may be occupied directly it is dry.

"Zinc white paint when pure retains its colour well, and will stand washing for several years without losing any of its freshness. When dry it becomes very hard, and will take a fine polish."1

This paint is suitable in large manufacturing towns where it is subjected to vapours containing sulphur, or in places where foul air is emanated from decaying animal matter. The zinc is not (like white lead) blackened by exposure to sulphuretted hydrogen.

In such positions of course zinc paint should not be mixed with "patent" or other driers which contain lead. The best driers to be used with it are sulphate of manganese and sulphate of zinc (see p. 413).

Zinc white is recommended as being preferable to white lead for painting on a dark ground. The reason for this is that the soap formed by the combination of the lead and oil in lead paints is semi-transparent, and the dark ground shows through it Another form of zinc paint is described at page 424.

Coloured Paints

It has already been mentioned that coloured lead paints are produced by adding a suitable pigment to a white lead paint until the required tint is obtained.

It would of course be impossible to give instructions for the composition of the great variety of colours and tints in which paint may be required.

A few, however, of the most common tints produced by mixing two or more colours may be mentioned.

The colours used are generally divided into classes as follows : -

Common Colours, including greys, buffs, and stone colours.

Superior, or Fine Colours, such as bright yellows, warm tints, cloud colours, and common greens.

Delicate tints, such as blue verditer, pea-greens, pinks, etc.

The following list shows the pigments that may be added to white lead paint2 to produce a few of the most frequently used compound colours.

The same pigments, except those containing lead, may be used with a zinc-white basis for coloured zinc paints.

Pigments for Coloured Paints.

Common Colours : - Stone Colour

Burnt umber.

Raw umber. Yellow ochre. Drabs. - Burnt umber.

Burnt umber and yellow ochre for a warm tint.

1 Seddon.

2 Or to white distemper; see p. 254.

Buffs

Yellow ochre.

Yellow „ and Venetian red. Greys. - Lampblack.

Indian red - indigo - for a warm shade. Egyptian blue - or French ultramarine - and vermilion - for a warm shade. Brown. - Burnt sienna, indigo.

Lake, Prussian blue (or indigo) and yellow ochre Superior Colours : - Yellows. - Chrome yellow.

Green

Prussian blue, chrome yellow.

Indigo, burnt sienna (or raw umber). Prussian blue, raw umber. Avoid arsenical greens. Salmon. - Venetian red. Vermilion. Fawn. - Stone ochre and vermilion. Delicate Tints : - Sky-blue. - Prussian blue.

Pea-green. - Brunswick green. French ,,

Prussian blue, chrome yellow.