A practical treatise on coach-building historical and descriptive

by James W. Burgess

From the above description, it will be seen that painting a coach is a tedious operation, and one which consumes a great deal of time in its execution; but, if well done, the result will certainly be very satisfactory. In no case should the painting be hurried, for by allowing each coat of paint or varnish sufficient time to dry its durability is insured.

A considerable amount of time is generally spent by the painter in work which does not really belong to him—that of mixing and grinding his colours. Where the muller and slab are used, they occasion a great deal of labour, and the tones of the colours are liable to be injured by the heat generated in the process; and even where the hand mills are used, the process is by no means so cleanly as it ought to be. And under the heading of waste, this must always be a source of loss to the manufacturer, for the painter, for fear of not mixing up sufficient colour for his use, generally prepares too great a quantity, and as a rule, the surplus is waste, for it is no use to employ stale colours in painting vehicles, however well it may do in house painting.

What we want is to have the colours ready ground for the painter’s hand, and against this has been urged the objection, that the delicate colours would lose their purity, and all colours be more or less affected by it. That this is utterly fallacious is seen by the fact that paints and colours ready ground and prepared are the rule in America. The invention of the machinery, &c., for this purpose, is due to Mr. J. W. Masury, of New York, and he grinds pigments of the hardest description to the most impalpable fineness without injuring the tones of the most delicate; and by a process of his own preserves them, so that the painter has nothing to do but to reduce them to the consistency he may require for the work in hand. He says they effect a saving of from 20 to 50 per cent. both of labour and material. It is difficult to understand why so valuable an invention is not more general in this country.

Irregularities in Varnish.

Varnish is subject to various changes after having been applied to a body or carriage part. It crawls, runs, enamels, pits, blotches, smokes or clouds over, and in the carriage parts gathers up and hangs in heavy beads along the centre of the spokes, &c.

These irregularities will happen at times with the very best varnish and the most skilled workmanship, and surrounded with everything necessary to insure a perfect job.

The only reason that can be assigned for it is atmospheric influence. These peculiarities have occupied a large portion of the time of the trade, and no other solution has been arrived at than the above.

The defects of varnishes should be divided into two classes: those which take place while in the workshop and those which show themselves after the vehicle has left the hands of the maker. The defects which show themselves in the varnish room are those of “spotting,” “blooming,” “pin-holing,” “going off silky,” “going in dead.” Those which take place afterwards are “cracking,” “blooming,” “mud-spotting,” and loss of surface, sometimes amounting to its almost total destruction.

The two classes should be considered separately; and assuming that the workmanship is of the best quality, the latter class of defects, with the exception of blooming, are in no way attributable to the varnish; and blooming is caused by the atmosphere being overcharged with moisture, as would be the case before a storm, and it is soon remedied. Cracking will arise from too great an exposure to the sun, just as any other material will be damaged by unfair treatment. Mud-spotting will arise from using the carriage in muddy or slushy roads before the varnish is properly dry. The loss of surface will depend largely on the coachman, who, from ignorance or negligence, may rub down the panels of a carriage until its glossy surface entirely disappears; and if the stable is contiguous to the coach-house this destruction will be assisted by the ammoniacal vapours arising from the manure, &c.

The other defects belong to the inherent nature of the varnish as at present manufactured, and admitting the secondary cause to be atmospheric influence, it is necessary to inquire why it is that varnish should be subject to such influence. According to the usual way of making varnishes, we know that various metallic salts and chemical compounds are used to increase their drying properties. All these will contain a certain definite amount of water, termed “water of crystallization.” If deprived of this water they lose their crystalline form, but they acquire a tendency of again assuming it by attracting to themselves a proportionate amount of water when it is brought within their power. Now the heat employed in making varnishes is sufficient to expel this water; but the presence of the salts is sooner or later detected, for when the varnish is applied to the work these salts absorb moisture from the atmosphere, and by becoming partially crystallized cause what is known as “blooming,” “spotting,” and “pin-holing.” The tendency to bloom will always remain, even after the varnish has hardened. But if any of these effects take place in the varnishing room, while the varnish is drying, it will be fatal to the appearance of the carriage.