This section is from the book "Arts & Crafts Magazine Vol1-2", by Hutchinson & Company.
The serviceable outfit by means of which I have, myself, practised pyrogravure, is known as the "Original, No. 3." The box, complete, can be bought from any dealer in artist's materials, or at any of the large "stores." The contents are a glass bottle with connecting cork, a spirit lamp, a small rubber hand-bellows, some rubber tubing, and a cork handle, to which is fitted the platinum point. This will be found to meet all ordinary requirements for the execution of surface designs.
Fig. I illustrates the Hat point which is usually supplied with the machine just mentioned, but, if preferred, any other point of equal value - there are many such - may be substituted. Some persons prefer the horn-shape point (Fig. 2), as being better adapted to give a variety of strokes; but it is more a question of practice than anything else. Personally, I consider the "extra fine" point (Fig. 3) the best of the three, especially for delicate work. For covering broadly large surfaces, there is the shading attachment (Fig. 4), almost flat at the end, and about twice as thick as the ordinary tool. The platinum point is by far the most costly part of the pyrographer's outfit, for, as the reader is doubtless aware, platinum is even more expensive than gold. It is one of the rarest metals; no acid has any effect on it, and it is the only metal possessing the peculiar quality of absorbing the heat conveyed by the hydrocarbon vapour obtained from benzoline. The usual attachments, being hollow, cost about half as much as the solid points. They must be used with care, for undue pressure upon the hollow point, while it is in an intensely heated state, would be likely to snap it. Nor must any attempt be made to examine the internal parts of the point, as it is only with great difficulty that the sheath can be replaced. Still, with ordinary use the point will last a considerable time, the first sign of wear being the appearance of very small holes on those parts which have been most in contact with the wood. When the tool gets to this condition it cannot very well lie repaired, but for certain kinds of work it will still be useful. If preferred, however, your dealer will return it to the makers, who will make an allowance for the value of the old platinum.
It occasionally happens that an new point is somewhat difficult to heat at first; or, rather, it does not retain the heat. In such a case, it should, after the operator has seen that the escape hole is free from dust, be held in the flame, and the bellows should be worked vigorously until a white heat is attained. This repeated a few times will usually result in the point working satisfactorily. Except for the purpose just mentioned, however, the point should not be brought to a white heat, as it tends to destroy the platinum and loosen the sheath.
Settle, with Pyrographic Decoration executed in relief.
When used on leather, plush, wood containing much resin (such as common pine), or unseasoned wood generally, the heat may form a chemical charcoal, which settles on the point. When the metal is cold, this must be removed with wash-leather and knife-powder; otherwise the platinum will soon be destroyed.
The quality of the benzoline constitutes an important factor of success in pyrogravure. Almost every case of failure to make the point retain the heat may be attributed to the use of the wrong kind. But there should be no difficulty in obtaining the right sort, which is that having a specific gravity of about 60 degs.; it is supplied by most oilmen. Benzine will not answer the purpose, but in case of need it may be used as a substitute if mixed with one-third of paraffin.
Generally, the bottle should be about half to two-thirds full. When quite new it is advisable to let the benzoline remain uncorked for an hour or so; but if the time cannot be spared, a good plan is to add about one-third of paraffin, which will reduce its strength. Many people prefer to put a piece of cotton wool into the bottle and to soak it well with the benzoline. This will give an increased heat on account of the evaporating surface being greater; moreover, it reduces the danger in case the bottle happens to upset.
To ensure good and lasting results in pyro-gravure, one cannot be too careful in the selection of wood, seeing that it is absolutely sound, well seasoned, and free from knots. If the wood is at all new, it will warp under the treatment of the hot point, and the work very likely will be spoilt. Closeness and even grain are more important than any other qualities. Sycamore, chestnut, holly, cedar, pear, bass and elm are all favourite woods, and, when well prepared, offer an agreeable, even surface for decoration. For relief burning, alder wood is probably the most satisfactory, as it is soft and easy to burn away. Where pokered articles are intended to be stained, sycamore and chestnut are specially desirable, as they often have pretty markings which show up well through the lighter stains.