This is the new modern way. Old way required the use of a lead sheet that was formed to look like a pipe to slip over the cable splice when it was completed. The ends were beaten down until the edges fit around the cable. Then the cable splicer had to pour melted lead in his hand and wipe the lead over the cable to seal the fitted cover. Of course he used highly insulated gloves that were up to his elbows. Still there were the occasional burns. I had hoped to find a video of this process but could not.
When wiping a lead joint you don't wear gloves, you can't feel the lead in your hand. All I used was a 12" square of moleskin folded to give me a pad about 6" X 4" it was then soaked in Russian tallow. Once that pad had been broken in a few times it was treasured, it fitted in to your hand beautifully. For a through joint a lead tube was used which had to be dressed (beaten down) at the ends to meet the lead sheath. A good mate was essential, you had to trust him to spoon molten plumbing metal in to the pad in your hand.
If it was a belted cable antimonial lead wire had to be soldered around the cores at the point where the belting ended to give stress relief. I had a look on the net for antimonial lead wire, it was £55 for five yards!
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The reports of my death are greatly exaggerated.