The term putty is applied to three very different articles. The mason or plasterer gives this name to a finely divided and smooth paste of slaked lime, used for filling cracks, finishing off delicate parts of the work, and similar purposes. The term is also applied to the oxide of tin, so extensively used as a polishing powder by opticians, and fully described in the article on "Polishing Powders" in Part I. In general, however, when "putty" is spoken of the article known as glazier's putty is meant. It is used for setting glass in windows, for filling cracks and nail-holes, and other purposes.
The best is made of raw linseed-oil and whiting, the latter being simply chalk ground in a mill like flour. It comes out with a fine flint grit in it. Before making putty of it, a few old-fashioned men, who believe in making the best of everything, wash the grit out. The fine flour is then dried. If it is not dried perfectly it takes up more oil than is desirable or profitable. From 500 to 600 pounds - about 15 per cent, by weight, of raw oil to 85 per cent of whiting - are put in a chaser and thoroughly mixed. The chaser is an annular trough, ten feet in diameter. From a vertical shaft in the center two arms extend, on the ends of which are heavy iron wheels that rest in the trough. When the shaft revolves the wheels chase each other around the trough. When mixed, it is packed in bladders for convenience in handling.
The adulteration of putty is effected by mixing marble-dust with whiting. It costs about a quarter of a cent a pound, and whiting costs twice that. Paraffine oils, at from 20 to 30 cents a gallon, are used instead of linseed-oil at 60 cents. The marble-dust makes the putty gritty, and the cheap oil makes it sticky.
A superior article of putty is made, however, by the further addition of white lead in oil, Japan varnish, and a small quantity of turpentine, which makes a hard cement that does not shrink, and when dry can be rubbed down with pumice-stone or dusted with sandpaper, so smoothly will it cut. Even in the common sorts of putty it is well to use some white lead if a hard putty is desired. Colored putty has a mixture of red ocher, lampblack, or other color, with the whiting.
For stopping large cracks, especially when leaks are to be stopped, the compound known as "aquarium cement," and described in Part I, is altogether the best material that can be used. For puttying up the cracks in beehives it has no equal, as it does not contract and fall out, and it is so hard that no vermin can penetrate a crack that has been filled with it.
Take the whiting, mash all the lumps out on the stone, and mix it into a stiff paste by adding equal parts of Japan and rubbing varnish; then add as much keg-lead as you think will make it work free with the knife; then add the reet of the whiting until you have it to suit you. This will sandpaper good with one day's drying. If you want putty that will dry quicker, take dry white lead and mix with equal parts of Japan and varnish, to which add a few drops of turpentine. This is very soft for puttying, but can be sandpapered in from two to three hours, it becoming perfectly hard in that time.
Take 10 lbs. of whiting and 1 lb. of white lead; mix with the necessary quantity of boiled linseed-oil, and add to it 1/2 a gill of the best salad-oil. The last prevents the white lead from hardening, and preserves the putty in a state sufficiently soft to adhere at all times, and not, by getting hard and cracking off, suffering the wet to enter, as is often the case with ordinary hard putty.
1 lb. of pearlash, 3 lbs. of quick stone lime; slake the lime in water, then add the pearlash, and make the whole about the consistence of paint. Apply it to both sides of the glass and let it remain for twelve hours, when the putty will be so softened that the glass may be taken out of the frame with the greatest facility.
This is made with water-glass (silicate of soda) and zinc-white, and is highly recommended as a putty for iron.