Hot knives?

First you need a matchbox, a pin needle, a straw, a drinking glass and a table...

Wait what kind if hot knives are we talking about?

With thin cord, I'm ok with the lighter melt method, but if I want to get a really pro looking end (looks just like the ends on the offcuts I buy from sterling), here's what I do:

Wrap tightly in masking tape (wide enough/offset so that your good end has at least half an inch left after you cut.)

Cut through the masking tape with a sharp blade.

Heat up a pan on the stove with a small square of aluminum foil on it until it gets to a temp where it will melt nylon.

Press the taped end firmly into the scrap of foil and hold for a few seconds.  Can always pull it back and check until you get a feel for it.

The tape prevents the rope from oozing as it melts--so the heat can penetrate deep while holding its shape.  You get a nice solid melt between the sheath and the core and it doesn't turn a burnt black color.  If you end up with sharp corners, you can touch them with some sandpaper or briefly roll them on the heat after the tape has been removed.

I thought this was a thread about smoking hash!

Someone, the gym or the store, will always let me use their hot metal thingy to burn my ropes or cord back together.

For the rare times I need to do this I just borrow the actual "Hot knife" at my climbing gym. 

Cook the sheath a bit then slice with a sharp knife. Then cook the end.

As others have said, stove+butter knife works great. Wrap a ton of athletic tape on the handle for insulation to keep your hand from burning. Works like a charm.

Bill Kirby wrote:

I thought this was a thread about smoking hash!

Someone, the gym or the store, will always let me use their hot metal thingy to burn my ropes or cord back together.

I was wondering what those electric box thingies do.

Take a old all metal butter knife and place it in a vise. Heat it up with a propane torch and it will melt and cut at the same time. 

I think it really has more to do with technique than anything else.  I'm lucky that I have access to a rope cutter (something similar to https://www.amazon.com/Pearson-Industries-438007-Electric-Cutter/dp/B000HRT1TC) at work, but at first, a lot of my cuts looked and felt like trash (burnt and blackened ends, sharp edges, etc).  Some of the cuts even ended up with the core and sheath separating.  I've ended up changing my technique from just slicing through to actually taking time to taper and melt the end completely, so as to avoid the sharp melted ends and make sure the core and sheath are properly sealed together.  However, I'd really like to know how Mammut does their cuts - they've got a really nice smooth taper to them.

Nathan Hui wrote:

 However, I'd really like to know how Mammut does their cuts - they've got a really nice smooth taper to them.

+1

Mammut "Sonic welds" the ends of their ropes. The best rope ends on the market. 

Sharp wood handled steak knife...heat end of blade until red on a gas stove.  Voila.

Kelley Gilleran wrote:

First you need a matchbox, a pin needle, a straw, a drinking glass and a table...

Wait what kind if hot knives are we talking about?

https://www.youtube.com/watch?v=yIe1YwZyjLM

^^^^^^

Lol! Thanks for that. I was actually thinking about that scene when I made the comment.

i do not understand .. how a normal handle of a knife burns the hand?

Just buy a hotknife if you think you'll be in the game for long.  I find that I use one all the time. For a while I just did the tape trick, but found pinching molten nylon was not good for the fingers.

You can use for shoelaces, any kind of cordage, webbing etc. anything made out of nylon or polyester (aramides?).

Much nicer and quicker.  If you are OCD, you can get the shrink wrap hardware store end caps and a heat gun to seal up the end. Put a small tag with the new length in between the rope and the shrink wrap and you won't have to wonder what the new length is...

When you say hot knife, this runs through my mind

Brother Numsie wrote: When you say hot knife, this runs through my mind

Been a long time since I smoked anything like that...it is a gap in my life I can't quite remember ;)

I've always put a tight wrap of electrical tape (now colored) around the rope when cutting with a hot knife, then fusing it all together with a propane (or butane) torch.  A few years ago I found a small butane torch/cigar lighter at a "party cliff" and have been using that ever since.

However, out in the field when setting a rap station with cord. (I always use cord. Since the load-bearing inside-cords are protected from sunight by the sheath, I believe it holds its strength longer than webbing.) a trick I've used is to cut the cord with elec. tape around it, and then put superglue on the end.  So far, even cord that's been out in the northeast's elements for 3-4 years has not become frayed and "bushy".

I've also used superglue around the last half-inch or so of climbing ropes I've cut (in addition to melting/fusing the end) as I just figure this provides additional bonding of the sheath to the inside cords.

Robert Hall wrote: I've always put a tight wrap of electrical tape (now colored) around the rope when cutting with a hot knife, then fusing it all together with a propane (or butane) torch.  A few years ago I found a small butane torch/cigar lighter at a "party cliff" and have been using that ever since.

However, out in the field when setting a rap station with cord. (I always use cord. Since the load-bearing inside-cords are protected from sunight by the sheath, I believe it holds its strength longer than webbing.) a trick I've used is to cut the cord with elec. tape around it, and then put superglue on the end.  So far, even cord that's been out in the northeast's elements for 3-4 years has not become frayed and "bushy".

I've also used superglue around the last half-inch or so of climbing ropes I've cut (in addition to melting/fusing the end) as I just figure this provides additional bonding of the sheath to the inside cords.

I have a rear bike rack where one of the weld points broke (was one of several on the top of the rack, so not a super important one).  

I took some polyester thread and pulled it all together with a square lashing and then coated it with superglue.  Been like that since 2010 and still holding strong.  Bike does't live outside, but has spent plenty of time in the sun and carrying loads as a commuter bike...and sometimes I do stupid things like stand up on the rack while coasting (still have hands on the bars, but that's got to be above the weight limit on the rack).

Not sure if superglue has any UV resistant properties...but polyester is better than nylon and there are probably enough layers that some strands get zero exposure.