Every decent mechanic knows that you finish off new cables with crimped-on tips. The tips protect you from the cables’ sharp ends, and they keep the ends from fraying or unraveling. If you work on bikes long enough, however, you’ll eventually find yourself needing remove that freshly-cut-and-crimped cable.
No big deal–just cut off the end cable and start over, right? Yes and no. If you look at the end of a new, single-ended cable, you’ll see that the individual strands are fused/welded together during manufacturing. When you cut a cable–even using quality cutters–you expose the ends of the strands. While this is normally not an issue, it can make inserting the cable difficult–or worse–cause it to unravel when threading it through the housing.
This is exactly what happened to me when I attempted to install a double-ended derailleur cable. One end was Shimano/SRAM-compatible, and the other end (which I needed) was compatible with Campagnolo shifters. I grabbed my trusty cable cutters, lopped off the un-needed end, and proceeded to install the now-compatible cable. No dice. The sharpened end of the cable snagged when threaded through the shifter, and after repeated unsuccessful attempts, one strand broke free, causing the cable to unravel.
I could have resorted to using a single-ended cable, but I had purchased several of the double-ended cables (hard to argue with a $1.99 price tag), and was bound and determined to make the them work. Initially I considered soldering the end of the cable, but as luck would have it, I didn’t have any flux that was compatible with the stainless steel cables. What I did have, however, was a small bottle of enamel hobby paint.
After cleaning off any remaining oil or grease with rubbing alcohol, I carefully dipped the freshly-cut end of the cable into the bottle of paint. When the paint had dried completely, I carefully removed any excess with a few swipes of emery cloth. Threading the paint-sealed cable through the shifter was effortless, with no snags or unraveling.
Since then, I’ve experimented with Super Glue to treat trimmed cable ends. Super Glue has the advantage that it dries almost instantly, and unlike paint, there’s no need to wait several hours for it to cure.