Repair your rope when it’s necessary for you to remove a section that has been damaged, cutting rope without fraying. Remember that only synthetic ropes will melt.
If you find that a segment of your rope has begun to fray or has been damaged in some way, it’s important to cut that segment out because your rope is no longer safe. You can use a knife to remove a segment but then you must apply heat to the end of the synthetic cut rope or else it will begin to unravel. This is called fusing the end. Synthetic ropes will melt, but your organic ropes will not; they will just burn or singe.
There are two ways to apply heat. You can use a flame from a match or lighter or you can use a heat knife. After you apply heat and you’ve sufficiently melted the entire end you can fuse the end by pressing with your fingers after it cools enough for touch. Don’t wait for it to cool too long or it will no longer be pliable.
When you use a heat knife, you can press the rope down and rotate the rope at the same time. Once the rope is cut, make sure you melt the edge on the knife and smooth out that edge so it is not sharp. If you don’t suffiently smooth out the edge, it can be sharp and puncture your other gear or cut you as well. Make sure when applying heat to the rope, you do not breath in the vapors that are produced. These fumes can be toxic.