The practical electroplater A comprehensive treatise on electroplating, with notes on ancient and modern gilding, and formulas for new solutions . that they maynot become detached in the operation of blackleading. The molder will add to the success of this operation byrubbing the plumbago well into the sides of the rules andtypes with a moderately stiff brush before taking the im-pression of the form in the wax. Stopping Out the Mold. In order to prevent the copper from depositing onsuch surfaces beyond the mold as have become coated BLOWING OUT THE MOLD. 221 I with plumbago, the operator scra
The practical electroplater A comprehensive treatise on electroplating, with notes on ancient and modern gilding, and formulas for new solutions . that they maynot become detached in the operation of blackleading. The molder will add to the success of this operation byrubbing the plumbago well into the sides of the rules andtypes with a moderately stiff brush before taking the im-pression of the form in the wax. Stopping Out the Mold. In order to prevent the copper from depositing onsuch surfaces beyond the mold as have become coated BLOWING OUT THE MOLD. 221 I with plumbago, the operator scrapes the blacklead filmfrom around the outside of the mold with a three cor-nered tool. This is done to destroy the conductivity ofthat portion of the mold where the deposit of copper isnot wanted. By this means the metal case is entirely ex-cluded from the circuit, the slow and annoying method ofpainting the back of the case with wax avoided, and a greatdeal of electrical energy and copper is thereby saved. Blowing Out the Mold. After the mold is polished considerable blacklead willbe found in the cavities, especially in the openings to the. Scraper. fine rules and dots of the letters, which should be entirelyremoved before the mold is metallized. Great care mustbe used in this operation, as any neglect may cause defectsin the shell, it being indispensable that the superfluousblacklead should be thoroughly washed out of the moldbefore it is placed in the vat. The superfluous blacklead is sometimes blown out ofthe mold with a bellows, but this is best performed by a forcepump with a rubber hose, to which a sprinkler or rosenozzle is attached. This is performed by laying the case face up on a shelf 222 THE PRACTICAL ELECTROPLATER. I in a trough, with only sufficient water to cover the face of themold. The water is then turned on from the pump, afterwhich the operator passes the sprinkler backward and for-ward over, and about 2 inches from, the face of the mold,for a few minutes,
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisheretcetc, bookyear189
