Laying and Repairing of Electric Telegraph Cables (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1878 Excerpt: ...compound, and spread it evenly and smoothly to cover about 1 inch of the original guttapercha coating. 6. Apply another layer of guttapercha and tool it down to cover one inch of the previous layer. 7. Finally, lay on another layer of the compound, smooth down the joint, and cool it in cold water, after which an insulation test is made in the usual way. (Three coatings are often used, especially if it is a large sized core.) B. MAKING A JOINT IN INDIARUBBER CORE. 1. Fasten the core between two vices, and remove the felt for 12 inches from each end of the core by soaking the felt with mineral naphtha, and then rubbing it off clean with carding. 2. Cut off 2 inches of the indiarubber and solder in the same manner as for guttapercha core, only using rosin instead of chloride of zinc. By using solving fluid the operation of soldering is rendered easier, but as indiarubber suffers when heated in a greater degree than guttapercha, and as the fluid attacks indiarubber, rosin should be used in preference. 3. Sear the surface of the indiarubber with a red-hot iron for 3 inches on each side of the conductor joint. 4. Clean well the seared parts with the glazed side of small calico squares moistened with mineral naphtha so as to leave a clean adhesive surface. 5. Taper the insulator down to the conductor about 2 inches on each side of the conductor joint with a pair of curved scissors, so as to make the pure indiarubber layer visible for at least of an inch. 6. Coat the conductor with pure rubber tape lightly laid on in a spiral form, commencing at the spot where the separator ends across to the corresponding place on the opposite side of the joint, and back again in an opposite direction. The ends are fastened down by pressing a clean heated knife on them, or ...