Cut the sleeve …
You will cut sleeving at a position where no object is (yet) inside the sleeve. You will typically cut cable sleeving with a diagonal cutting plier or a universal scissor. Please do yourself a favor and use a good / very good tool. Don’t use a worn out tool. You will directly see if the cut is good or bad (showing you the protective qualities as a side effect).
It makes a difference where you cut the sleeving. If you cut it very close to where you hold it, you will get the best result.
Because the sleeving always has the tendency to open its weave structure at the cut. As it’s expandable, it will separate the individual strands a little bit and the sleeving will „open“ its structure and expand its diameter. That’s why you hold it with your fingers from all around very close to where you cut. It’s also the reason why you will typically not cut sleeving while it’s already on the object.
… and melt the cut area
After you have cut, keep holding the sleeving between your fingers, put the cutting tool aside, grab a lighter and ignite the flame. Now move the flame very close to the cut area until you see that the heat is melting together the ends of the little strands in the cut weave.
The flame will be very close to your fingers, so don’t burn yourself. Remember: Keep holding the sleeving at the cut area, so it’s basically at its own minimum diameter.
Once done, put away the lighter, keep holding the sleeving in the same position. The melted cut area needs to cool down a few seconds until the material hardens again.
You will quickly learn to melt just enough, not too much, not too less:
- If you didn’t melt enough, the sleeving cut area will fray when you press it e.g. onto a surface or the object.
- If you melted too much, you will have a thick ring of melted thermoplastic on the cut area, often making it too hard to put it onto an object of bigger size (than the cut area is at this moment).
There is also a tool, which cuts and melts at the same time. It’s called a „hot knife“. Let’s do it with simple things (cutting tool and lighter) in the beginning, because you typically have more precise control over the cut & melt result than with a „hot knife“. Some people also use cutting tips for their soldering iron, which can be useful in special challenges, especially if the sleeving is already applied to an object.
Well done. Let’s sleeve an object!