* Commercial hydrochloric acid saturated with zinc, and when poured off from the excess of metal, is mixed with i its bulk of hydrochloric acid.

Although very little care and attention on the part of the workman will enable him to use ordinary soft solder of the tinman without fear of melting the adjacent parts of the plate, there are cases where it may be desirable to use a more fusible solder, in which case Wood's cadmium solder may be employed. It melts at a temperature considerably under that of ordinary solder, works nearly as easily, and is quite as strong. It is prepared by melting together cadmium 2 parts, tin 4 parts, lead 2 parts.

An alloy of bismuth 2 parts, tin 1 part, and lead 1 part, forms a solder easy to use, moderately strong, and melting below the boiling point of water. When figures have to be altered several times, this solder is convenient to use, as those first soldered in can be readily removed by immersing the plate in boiling water or heating it till, when feel steam formed, then giving the figure a slight tap to drive it out.

Soldering bit.

Soldering bit.

It stereotyping for newspaper work, everything; is care fully studied to attain siieed, especially in the case of the evening papers, and it becomes possible to mould a page and cast a plate in about 10 minutes. In inch cases, the plates are east curved, so as to fit the cylinder of the machine used. ' Two workmen beat the flong to make the mould; a rolling press being often used to finish the moulding. There is generally very little packing of the whites to bo done, so it suffices to sprinkle a little whiting upon the back of the mould, and scrape it into the hollows with a straight-edge, after which the final thickness of brown paper is pasted on, and the forme is run under a hot press to dry, the heat being as great as can be ventured upon without damage to the type. In 2-3 minutes the mould is removed, finally dried on a hot surface for another similar period, is dusted with French chalk, and is then placed in a curved casting-box (Fig. 315), the metal being poured in at the side of the page, while in the older pattern of curved casting-box it was poured in at the top. The metal is poured from a large three-handled ladle like that used in iron foundries.

The trimming of the cast is generally done while it is warm, and by slow-moving tools, as chips rapidly removed from the hot metal are more likely to weld on the freshly-cut surface than is the case with cold metal. Therefore, the ordinary machine for boring the inside of the cast, and in which a single knife is made to revolve slowly and take one heavy cut (Fig.316), is less unsuitable than might at first sight be supposed. But in this case, if a revolving cutter were used, and were fed with slightly soapy water by a, series of conduits in the cutter-bar, it is quite likely some economy of time would be effected. Soap, like oil, soils the surface of the type metal sufficiently to prevent welding.

A common form of apparatus for trimming and bevelling the edges of the curved stereotypes is that shown in Fig. 317, the plate being clamped down on a suitable saddle, and trimmed by adjustable knives, the holders of which are moved backwards and forwards by hand. Another trimming machine is represented by Fig. 318. In this case we have a revolving cutter and the plate is fixed upon a saddle which traverses and rotates by hand gearing.

Occasionally pistes intended for print, ing on rotary machines are cast flat and afterwards bent to the required curve, and there are two methods of doing this. In one case the plate, previously warmed, is forced down into a laid oyer the die. In the other cose the stereotype is laid between steel plate thin enough to spring, and is roiled several times through a set of 3 rollers, one of which is adjustable so as to give the required let.

Casting box for curved plates.

Casting-box for curved plates.

Machine for boring inside of curved plates.

Machine for boring inside of curved plates.

Working Details Of The Paper Mould Process Part 9 500215

In either case, it is necessary to place paper or a blanket between the face of the stereotype and the steel plate, and the results of the bending are seldom quite satisfactory, unless the plate to be bent is fairly solid, as in the cose of an ordinary newspaper page, any ei-tended whites interfering with the, regularity of the bending. In the case of electrotypes, which are ordinarily backed up with a softer metal, the bending is easier, and electrotypes are often bent that they may be soldered into curved plates for illustrated newspaper work.

The work of the newspaper stereo-typer is very seriously interfered with if any wood-mounted blocks are inserted in the forme he has to mould, the heat passing so much more slowly through wood than through metal as to make it almost a matter of certainty that the mould will be less dry when over such blocks; this being not only calculated to give a rough face to the lines, but also to lead to a distortion of the face of the mould in the second drying. This evil is especially apparent in the ease of the zinc process blocks, which are made very thin, and are consequently mounted on an eitra thick block of wood. The separate moulding of the blocks and casting type high, or the mounting of them upon solid metal bases, is so easy that there is scarcely an eicuse for being so unfair to the workman as to send pages containing wood-mounted blocks when a stereotype is required in a minimum of time.

Probably the interfering influence of the wood mount is largely responsible for the tradition that the paper process is unsuited fur the reproduction of the finest engraved work, but personally I reasonable precautions* are taken to ensure the very-best results, stereotypes can be made by the paper process, which are equal in fineness of surface and definition to the best electrotypes, and are superior in durability to many of the very thin shells of copper on a base of very soft metal, which pass now-a-days. The paper process is, however, very ill adapted for moulding direct from wood cuts, owing to the action of the heat and moisture on the wood; and it is seldom employed for this purpose unless in the case of very small blocks, or when time necessitates it. The stereotype by the paper process is, when at its best, smooth, brilliant, and lustrous on the face, where the metal takes the impress of the compressed and hardened matrix; while the low parts, which are cast in contact with the spongy part of the mould, are always rough and often unsound in the sense of being permeated by holes and faults.