On Painting.

The Scientific American 17, 6.1.1855

(For the Scientific American.)

No trade in our country needs improvement more than painting, especially in regard to durability. The most common error in painting grows out of the idea that spirits of turpentine is a dryer; or, in other words, has a drying effect upon oil and paints with which it is mixed; hence it is used indiscriminately by painters to make paint dry, when the fact is, it only diminishes the quantity of oil used, and evaporates very soon after the paint is spread on wood, without having imparted any drying quality to the oil or paint. The only proper use of spirits of turpentine in painting or varnishing, is to reduce dry paints or gums to a consistency capable of being spread out, as in painting or varnishing, and if we could spread out the other ingredients on the same surface, without the turpentine, we might dispense with its use. For example, to make a hard paint that will bear rubbing down with pumice stone, take dry paint of any kind, and oil sufficient to make a hard cement, when spread out and dried, then reduce it with turpentine to a consistence that may be spread with a brush, and when the turpentine evaporates it leaves a hard body composed of the paint and oil. Again, take gum copal or rosin, by heating and mixing with the turpentine we reduce them to a liquid state, and can use them for varnishing; and when the varnish is spread, the turpentine evaporates without having imparted any essential quality of drying, luster, or durability to the varnish. Hence no turpentine should be used in painting intended to stand the weather, as it can be reduced to a proper consistence with oil, and made to dry without injuring its durability.

Paint, to stand the weather, depends en the wisdom of adopting the lifeboat principle tirely on the oil for its durability. For example take very thin oil in warm weather, and mix with white lead or other paint, and some turpentine for a dryer; the whole being of the consistence of common paint, put on three coats and it soon looks dry and dead, in a year or two will begin to rub off like whitewash, because the proportion of oil to the paint was too small. Again, take the same quality of oil and paint in cold weather, when the oil is thicker, and instead of turpentine, use some good dryer; mix to the consistence of common paint, then put on three coats, and it dries with a gloss and looks better at the end of four years than the other when first done, and will preserve the wood well for many years, simply because the proportion of oil to the dry paint is greater.

But all painting cannot be done in cold weather, and the question occurs, can it be done by using very thin paint, and putting on more coats, but the best way is to boil the oil; boiled oil is best at all times, but should be boiled more in warm weather than in cold. It can be boiled in an iron, copper, or brass kettle, and should be done over a slow fire out of doors, as there is danger of it taking fire; to every gallon of oil put in a quarter of a pound of litharge, which will make it dry. For hot weather, keep it boiling two or three hours; for cold weather, half an hour is sufficient; stir it frequently. A litttle prussian blue ground in oil, and put in white paint, improves its appearance. Sufficient time should be given between coats to let the paint dry well, and no outside painting is well done until it has a good even gloss.

For chair and other painting, where you want a hard body to rub down, or wear well, grind dry paint with a small proportion of oil, and reduce to the proper consistence to spread with a brnsh; use driers in proportion to the oil; if the oil is boiled as directed, for outdoor painting no drier is needed. Put on coats sufficient to make as good a body as you require, giving time for each coat to dry well. If it has a gloss when done it is from using too much oil, and will not rub well. There is not much danger of using too little oil for this kind of work, give it the gloss with varnish.

Spanish whiting and water, with a little glue, make a good and cheap priming for chairs; it should be put on warm. Persons wishing to paint their own chimney-pieces or carriages black, should put on one coat of lead color, made of white lead and lamp-black, using some turpentine and a drier; when dry, sand paper well, and finish with copal varnish and a little lampblack.

DRIERS - White lead has a drying effect on linseed oil, and paint made of white lead and oil, will always dry on new wood. Burnt Turkey umber, litharge, red lead, and sugar of lead, will all dry paint when ground with or in any way incorporated in it., But the best drier I have ever seen used is made as follows: —Take one gallon linseed oil, one pound red lead, one pound litharge, one pound Turkey umber, burnt nearly black and pulverized, and half a pound ground shellac; it is best to run the whole except the gum, through a paint mill, put into an iron, copper, or brass kettle, and boil slow until it will not show a grease spot through brown paper when dropped on it hot; keep it well stirred. When done, set it off and let it cool until the spirits of turpentine can be poured in without taking fire; pour in about two gallons of turpentine slowly, stirring all the time, more or less will do, as the thicker the drier the less will be necessary in paint; a half pint is sufficient for a gallon of oil in the paint on any new wood, but on old inside painting a little more will sometimes be necessary. It takes three or four hours boiling.

- A. W. H
Platte City, Mo.

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