Manufacturer and builder 6, 1869
Every reader of rural literature must remember the unmitigated ridicule with which Downing, the apos-tle of rural art, attacked our bright white houses and bright green blinds - houses which, in general, appear so fresh and neat that some one has said that they looked as if they had been put up on Saturday night and were to be taken down again on Monday morning. So long as this taste prevailed, there was little room for the exercise of choice in the selection of paint; at least, so far as the preponderating color - the white - was concerned. In regard to the greens, a little greater latitude was perhaps allowed; but the white almost invariably consisted of the well-known compound of lead. At the present time, our tastes in this direction have so far changed that we are no longer under the necessity of confining ourselves to any special chemical. compound; but are at full liberty to choose that which not only presents the best appearance but is actually best in other respects. For while the application of paint is of great importance as a mere beautifier, it is of equal, or perhaps greater importance as a preserver.
Paint as it flows from the brush of the craftsman, in general consists of some finely-powdered and compara-tively indestructible substance mixed with oil. To this mixture are sometimes added various matters, for the purpose of causing the paint to dry quickly, to spread freely, etc.; but in general all these admixtures are regarded as injurious, and are merely tolerated on account of the special effects produced by them. For in-door work, it is true, they are not so objectionable. The objects being in this case protected from the effects of the weather, the durability of the paint becomes sufficiently great to satisfy any reasonable demand; and it is, therefore, the habit of painters to use a greater proportion of dryers and turpentine in in-door work thin would be allowable for articles exposed to sun, winds, and storms. As a medium for the application of paint, nothing is equal to good linseed-oil, either raw or boiled. The boiled oil dries most rapidly and is most generally used; but for out-door work the raw oil answers very well, and is, perhaps, more durable. Oil which has been boiled too much, which has had too much of the drying property imparted to it, is, in reality, injured thereby, and does not last as long as it otherwise would have done. But oil alone will not form a paint. It has been denied that it can form even the basis of a paint, though this latter position is one which savors more of dialectic subtlety than of practical clearness of vision. One thing absolutely certain is, that without good oil the best paint is utterly worthless as a preservative. It would be possible to tint a house or a wagon with Venetian red, mixed with water, and if a little milk or blood were added to it, it would not rub off readily when dry; and yet, it would be a poor preservative, although the same paint mixed wills linseed oil would furnish a preservative coating of the most superior character. The character of the oil, then, is of the greatest importance. Good oil will confer upon paint a durability which can never be attained by the use of a poor article.
To form a paint, the oil must be mixed with some substance in the state of a very fine powder. There are two processes by which the materials used for this purpose are attained in a finely divided state - one being chemical, and the other mechanical. Thus lampblack is deposited as soot in the form of a powder, which is sufficiently fine without any grinding process; while baryta and many of the ochres require to be submitted to the action of powerful grinding mills before they can be used as pigments. In all cases, however, it is necessary that the pigment be finely pulverized, otherwise it will neither work well nor last long.
Thus far we have considered paints chiefly as pre servatives; our reasons for so doing being the fact that, if our selection be judicious in this respect, it is an easy matter to provide for color Within certain reasonable limits. Hitherto, a most singular error has prevailed amongst the non-professional public, who almost invariably regard the compounds of lead as among the most durable paints in existence. Now, it so happens that the beautiful and expensive white lead is one of our least durable pigments, while red lead is far less efficient than Venetian red in affording protection; and indeed, it may in general be affirmed that those earthy paints, or oxides which form mere mechanical mixtures with the boiled oil and have no special chemical action thereon, are invariably the best protectors. Of late years, enormous quantities of these earthy or mineral paints have been produced in this country; and the variety of shades which may be obtained has been so great as to leave little further to be desired in this direction. One company - The Pecora Paint Company of Philadelphia - manufacture a great variety of colors and shades from certain earths which are found in great abundance.
In selecting a paint for the purpose of protecting any object which is fully exposed to the weather, it is well to avoid all very dark colors, as these are apt to absorb the sun's heat to such an extent as to injure the material over which they are spread. This is especially the case in regard to tin roofs, which should always be covered with light colored pigments, as otherwise the roof itself, and the chambers beneath it will be rendered intensely hot. It is true that the very darkest paint - lampblack - has been found a most efficient protector, as may readily be observed on old signs, where the letters, painted in black, have outlasted the white portion of the sign. Even the wood beneath the white paint will, in general, be found to have decayed and become worn by the influence of the weather; while the wood beneath the black paint still remains sound, and elevated above the general surface like the embossed letters on initial paper. But at the same time, it must be remembered that the lampblack has proved thus preservative in spite of its color and not because of it. It is chiefly to the fact of its indestructibility, together with its property of forming no chemical compound with the oil, that it owes its great durability and preservative power. These facts teach us that the best protecting paints are those formed of earthy bases and having comparatively light colors .