Lessons in Metal Work (Part 3)
Last month I left the practical part of this lesson at the point where the pitch-block has just been made. Supposing this operation finished, the next is to prepare the metal for working.
This is done by seizing it in the corner by one hand and striking it flat on a table. In this way bends and creases are taken out. The next job is to fix the metal on the pitch-block, and for this purpose it is warmed till one can just bear one's hand on it. The metal must now be pressed on to the pitch-block and fastened down at each cornerawith nails.
The surface uppermost, which will be the front when the design is finished, must now be cleaned, and the working drawing laid over, it being fastened with pins into the pitch outside the edges of the metal. A carbon paper intervenes of course, and by means of a style the design is transferred to the metal. The drawing is then removed, and the outlines of the design gone round with a No. 3 blunt tracer.
The metal is next taken from the pitch-block and raised from the back after having been thoroughly cleaned. The cleaning consists in clearing away pieces of pitch which may adhere. For this purpose the metal is warmed, and with a paraffined rag the pitch is easily taken off. Now the metal is placed face downwards on the block and the embossed portions raised. Round the outlines a small square stem raiser is used for the purpose of getting the relief clear and defined. Afterwards a sort of undercut is given from the front.
Here I must leave the general lesson for the moment, merely remarking, in answer to a correspondent, that the Canaux is used for double lines, but wants a good deal of practice to be successfully employed.
And now a word as to the designs. For the hinges, flanges are left subsequently to be turned over a wire running through them. The embossed stems outlining the hinges are produced with a stem raiser just inside the margin of metal. This margin is then carefully trimmed off with shears. The handles for the plates may be either cast or purchased in the nearest shape obtainable. Better still, they may be hammered up in two halves and subsequently soldered together by a smith.