The enormous increase in recent times in the use of ready-mixed paints by the trade may be taken as an indication that the prejudice which was felt against them in the early years of their existence is rapidly dying down. However much this prejudice may have been justified in the past, it certainly cannot be upheld to-day, and though there is a fair number of men who still prefer to make up all their own materials, the popularity of ready-for-use paints is steadily growing, and it is by no means unlikely that, in course of time, they will entirely supersede those made in the traditional manner.
The advantages of ready-mixed paints will readily be appreciated. Modern machinery and methods are obviously able to produce a better ground and mixed paint than the painter can make up for himself, and since the manufacturer buys his materials in bulk, the factory-made paint costs no more. The fact that such paints are marketed in containers of convenient size is another strong point in their favour.
The chief objection usually urged against ready-mixed paints is that there is no indication as to the nature of their contents. It is sometimes suggested that, as a safeguard against possible abuses, manufacturers should print on the container or its label a full list of ingredients, but in certain States in America and Australia where regulations to this effect have been enforced, it is doubtful whether any advantage has ensued; it is hardly fair to expect a manufacturer to disclose the exact formula which he uses, and even if he does so, it requires rather more chemical knowledge than the average decorator possesses to understand its full implications. On the other hand, a mere list of ingredients without any quantities added is quite useless.
In purchasing ready-mixed paints or any other materials, the decorator’s best safeguard is to buy only those products made by firms of established reputation.
One word of advice to those who employ ready-mixed paints seems desirable. Use only the thinners recommended by the manufacturer in the proportions stated on the container, and on no account attempt to add driers or any other material if their incorporation is not advocated. The modern factory-produced paint is made to a scientific formula, and any unauthorised addition may easily destroy its balance. Should any defect occur from this cause after application, the manufacturer will naturally decline any responsibility, and the onus of making good will fall on the decorator.
Before enumerating the various classes of paints and enamels normally used by the decorator, it is as well to point out that it is not easy to make any hard-and-fast distinction between some of them, since the names by which they are described are not precise and are subject to widely different interpretations. It is hard, for example, to state the essential differences between an enamel, an enamel paint, and some types of hard-gloss paints, and it is probably safer, in general, to regard these as different grades of a similar type of finish.
A mixture of pigment, drying oil, drier, and thinner. The pigment, ground in oil, may be obtained in stiff paste form, to be made ready for application by the user by the addition of more oil, with thinner and drier; alternatively, oil paint ready for use, with all essential ingredients incorporated, can be supplied.
An oil paint which dries almost flat, with a minimum of gloss, usually obtained by thinning the pigment ground in oil with turpentine or white spirit, but without the addition of more oil.
By thinning down the paste with approximately equal parts of oil and turpentine (or white spirit), a paint which dries with a semi-gloss finish is obtainable. Varying degrees of gloss can be got by varying the proportions of oil added to the paste.
There are many formulations for this class of finish but, broadly speaking, it dries with a higher degree of gloss than an oil paint and has a harder film. Whereas oil paints have to be well brushed out to give an even coating and show brush marks unless they are skilfully applied, hard-gloss paints have, in greater or less degree, the property of ‘ flow’ so that, when applied, ridges or channels left by the passage of the brush are eliminated. This property is imparted by using special media, which may be heat-treated oils, varnishes, or a combination of both. Varnish Paint
A paint similar in composition to a hard-gloss paint, but generally inferior in quality.
Enamel, Enamel Paint
These terms cover many different formulations but are generally taken to imply a high-grade finish, made on lines similar to a hard-gloss paint, but superior to it in durability, moisture resistance, and elasticity.
Flat Wall Paints and Enamels
A range of oil paints formulated to dry with a mat finish and to be applied with a broad brush on interior wall surfaces. They give a smoother film than washable water paints, wear longer, and are scrubbable.
These are prepared by grinding the pigment portion in a vehicle consisting of bitumen and drying oil but, owing to the dark colour of the bitumen, are available in only a few dark colours. They have excellent moisture-resisting properties and are consequently extensively used for exterior surfaces, particularly those of ferrous metals, but are liable to bleed through and discolour ordinary oil paints which may subsequently be applied directly over them.