Cut rope with itself
By the staff of Trucks & Guns Magazine
Cutting rope with itself is an old trick that has been passed down from generation to generation. Most likely your grandfather or father taught you how to do this many years ago. It is also likely that you have never used this trick and you may never need to. We are sure that just like us you carry a knife with you everywhere you go, and feel naked without it. With that being said, this is a cool trick to know if you ever leave your knife inside your truck and you need to cut some rope. The purpose of this article is to try to help you not waste time and energy by trying this on rope that is difficult or near impossible to cut with itself.
HOW IT WORKS
The science behind this is very simple. Depending on the type of rope, friction makes heat and melts the rope and creates imperfections of the fibers that will wear on each other, cutting the rope. To explain this we will have two sections of the same rope, the section that will be cut (A) and the section doing the cutting (B). The simplest way to do this is to stand on top of section A with about two feet of slack between your legs. Then pull section B under section A and place your hand on section B with one hand on either side of section A. Move section B back and forth quickly, making sure that you move section B on the same spot on section A. Rubbing the rope against itself as fast as you can will cut the rope. If you have something to tie to, this technique can be easier, but if you are taking the time to tie and untie knots it probably easier just to find a knife. To do this, tie a large loop around something stable and feed section B through the loop.
TYPES OF ROPE
This is easier with different types of rope and is nearly impossible with other types of rope. So we decided to see what ropes work and what ropes do not. We went to our local hardware store and got about ten feet of seven different types of rope. It actually turned out to be kind of interesting, because a few of the ropes we thought would be easy turned out to be difficult. It is also not as easy as it sounds with thick rope, as it takes time to build up the heat needed to make this work. The types of rope we tested were: Solid Braid Polypropylene (red and white), Manila Rope (tan), Diamond braid Polypropylene (thicker white), Cotton Sash Cord (thinner white), Twisted Polypropylene (yellow), typical Truck rope (black and orange), and Twine (small tan). Even though most of these are Polypropylene based, they all had a different texture and weight. This selection should cover the standard ropes you would normal come across.
HOW WELL IT WORKED
We were able to cut four out of the seven ropes using this technique. Although the only two that we felt were time-effective were the twine and cotton sash. The Solid Braid Polypropylene was a very soft-to-the-touch rope, like it was made of an organic fabric-like material. This made the rope slide across itself without building up a lot of heat. It did eventually cut but took a solid ten minutes, and we had to apply more pressure than with any of the other ropes. The Truck rope was also very difficult but did cut through in time. The Cotton Sash Cord did not take long to cut through, and this proved an effective method to cut the rope. The Twine was obviously the winner, it was so thin and course that it only took a few passes to cut through.
WHAT DID NOT WORK
We were surprised the Manila Rope would not cut through itself. As we moved it back and forth it only made a smooth spot on the rope. This being made of a plant fibers and coarse feeling we thought for sure this was going to be one of the winners, but no matter how fast or hard we moved it across itself it did not change.
The Twisted Polypropylene rope had such a large twist that it did not have the surface-to-surface contact to build up the heat needed to cut. We got a few strands to melt but that was it.
With the Diamond Braid Polypropylene rope, the friction melted the outside braid but the inside strands just stretched, which brings up the point that this technique is difficult or nearly impossible with rope that has an outside braid with strands on the inside, like paracord.
Although speaking of paracord, this technique does work very well on paracord, as paracord has a low melting point and you are simply using friction to melt the cord.
Buy a knife, carry the knife, and keep your knife sharp. Yes, this technique works on some ropes but it is a lot of work. If you have to, we hope this article will help not waste your time. If you are in a survival situation and you lost or broke your knife and you need to cut your paracord, well, now you know you can.
Polypropylene is a thermoplastic polymer.
Manila is a type of fiber obtained from the leaves of the abacá, which is a species of banana.