Good putty for the use of painters and glaziers cannot well be made without the use of a chaser or edge runner mill, because only a thorough kneading will produce the proper mechanical union between pigment and oil. Strictly pure whiting and linseed oil putty consists of 85% by weight of whiting and 15 parts by weight of pure raw linseed oil. Exacting consumers, who do not consider first cost so much as wear and durability will specify linseed oil, whiting and white lead putty and the usual rule is to use, in the pigment portion, 10 per cent by weight of pure white lead. 78 lbs. by weight of whiting, 8 lbs. by weight of dry lead and 14 lbs. by weight of linseed oil are the right proportions for this sort of putty. The batches are regulated as to quantity by the size and capacity of the apparatus and when the mixing is well made, the material is discharged from the chaser and placed on the floor in heavy layers to undergo, what is termed a sweating (or ripening) process, occupying several days and nights, when it is replaced in a chaser for a second operation of kneading, which is continued until the putty will not stick to the hands, when using. Unless so treated putty will not work well, nor hold well. Putty of this character can be obtained from reputable manufacturers, when the consumer is willing to pay the price, but over 90 per cent of all the commercial putty sold by jobbers and dealers cannot be properly classed as linseed oil and whiting putty, most of it being made with non-drying oils, the better grades with corn oil, others with so-called paint and putty oil, and in many cases, marble dust replaces part of the whiting. Oil foots are also used with putty of this class, that is made to supply the demand for cheapness, which has been fostered by the trade themselves by giving away putty when selling glass, thus creating an idea, in the minds of buyers, that putty is of no value. When putty of the quality last mentioned is used for glazing sash and closing up nailholes, it will not dry as it should, by oxidation, but simply hardens, in time, to a brittle mass and the slightest vibration will often make it lose its hold, crumbling out of its place.
Boiler cement can be made by grinding 24 parts by weight each of dry white lead, kaolin (clay) and black oxide of manganese, all powdered in hard gum varnish (not manila gum), that does not dry in less than 24 hours of itself. It will require 30 parts by weight of varnish, the batch producing 100 parts by weight after grinding on a watercooled mill. It will stand hot water after hardening and high degrees of heat.
Roof cement for stopping leaks in tin and iron roofs is best made by boiling paint skins in raw linseed oil, until all the skins have softened, and when cooled somewhat, the mass is placed in a mixer, more dry pigment or oil is added as may be necessary and then run loosely through a paint mill. It should be in the form of a paste. Varnish bottoms with mineral pigment can be utilized in a similar manner.
Rivet Head Cement or composition is usually made by grinding equal parts pure red lead and whiting in boiled linseed oil and japan, two parts of the former and one part of the latter. It should be ground to order only, on account of the hardening tendency of the red lead with drying oil and japan. It is best made in soft paste form, grinding say 40 lbs. dry red lead and 40 lbs. bolted whiting in 14 lbs. boiled oil through a mill and then adding in a mixer 7 lbs. japan.
If wanted in black, rivet head composition is made by grinding 10 parts by weight of white lead, 5 parts by weight of litharge, 50 parts by weight of black filler in 15 parts by weight of boiled linseed oil and 20 parts by weight of hard gum japan. A small percentage of lampblack added will give the composition more depth. As these compositions must dry flat, they must be prepared in a form stout enough to admit of thinning with turpentine or benzine.