Need Advice on Building Rope Cutter using specific items

Janis59

Joined Aug 21, 2017
1,849
RE:""How realistic is it that your heroine is going to know exactly what""

This made me remember an old pupil-style anecdote: In the school the teacher of literature asks Peter - did You read at Your summer vaccations the russian Anna Karenina as we agreed at last spring? Yes teacher, I do. So, and what You think there about heroine? Ouch teacher, heroine is one damn strong thing.... but why You are asking about?!
 

Janis59

Joined Aug 21, 2017
1,849
However, practically, if the count of cutted ropes are below the 100, I would never make an any machine. But sitting with the sharp knife on the taburette and cutting cutting cutting. Better alternatives are flex-machine (aka angle grinder) or steel cutting giljottine. Then take a lighter of candle and make the ends burning job.
 

jpanhalt

Joined Jan 18, 2008
11,087
What if the bad guys decide to use Manila rope or sisal rope? That's what was used in old movies and still is for hanging.

Maybe a little battery acid and high nitrogen fertilizer will "cut" it.
 

WBahn

Joined Mar 31, 2012
30,045
However, practically, if the count of cutted ropes are below the 100, I would never make an any machine. But sitting with the sharp knife on the taburette and cutting cutting cutting. Better alternatives are flex-machine (aka angle grinder) or steel cutting giljottine. Then take a lighter of candle and make the ends burning job.
She's not trying to start a manufacturing operation and she's not trying to keep the rope from fraying after it's cut. She the heroine in a story who is trying to escape captivity and the plot device is that she improvises a hot-wire cutter in order to cut one wire. So the cutter only has to last long enough to cut one(?) rope (of as yet unspecified material or diameter).

If the light bulb method proves too fragile to jury rig something, then it could still be used to demonstrate the notion of thinking of an approach and it not working and, after some amount of effort and adjustments, moving on to something else -- perhaps using the bulb base with the broken glass sicking up from it to simply cut the rope. That could be done in either a comedic way, or in a straight-up way. She's looking around and, having seen what appears to be a charged car battery, thinks of a hot wire cutter and is looking for wire. She then comes across the box of bulbs. Since she is already focused on the hot wire approach, she breaks a bulb intending to use the filament, but it immediately crumbles at the touch. So she's standing there holding the broken bulb and considering the other bulbs in the box when she looks back at the base of the broken bulb and realizes that the glass might be sharp enough and strong enough to cut the rope.

That not only gets a glimpse of some science, but also at human foibles such as target fixation and how a good heroine needs the nimbleness of mind to always be looking for alternatives.
 

Janis59

Joined Aug 21, 2017
1,849
RE: Nitrogen fertilizer

Then why not cut the ropes with ANFO?
en.wikipedia.org/wiki/ANFO will show the ropes how and what. :) :) :)
 

MisterBill2

Joined Jan 23, 2018
18,463
A silver necklace will drain the battery too fast without generating enough heat. A steel hair pin, being wire, across a single "D:" cell will get quite hot, and could melt a nylon or polyproplene rope.
Of course, MacGyver tricks, while sort of following laws of physics, would very seldom actually work in a real world. That was always my complaint about the guy. Connecting a garden hose to a scuba tank to inflate a beach toy to pop open a jammed door? I really don't think so.
But a steel hair pin can be bent to contact both ends of a "D" cell , and the ends could easily be held without getting hot. OR the person could use two shirt buttons held in place to keep cool fingers. Available materials, believable actions, and physically reasonable.
 

Danko

Joined Nov 22, 2017
1,834
She used nail lacquer remover.
Small bottle of them always exists in her handbag.
Only put one drop on poly rope...
 

jpanhalt

Joined Jan 18, 2008
11,087
Question #1: If the distressed maiden is tied up "fest", how will she be able to do all the manipulations contemplated here? If her hands are free, why notjust untie the remain ropes and use them to escape or build a trap for her captors?
 

jpanhalt

Joined Jan 18, 2008
11,087
RE: Nitrogen fertilizer

Then why not cut the ropes with ANFO?
en.wikipedia.org/wiki/ANFO will show the ropes how and what. :) :) :)
Most Americans are familiar with ANFO from the Oklahoma City bombing years ago or Galveston.

I was thinking of the mixture with H2SO4 as a strong oxidizer. I suspect the heroin wants to be free rather than spontaneously disassembled.
 

WBahn

Joined Mar 31, 2012
30,045
Question #1: If the distressed maiden is tied up "fest", how will she be able to do all the manipulations contemplated here? If her hands are free, why notjust untie the remain ropes and use them to escape or build a trap for her captors?
Whether she's tied up or not isn't clear -- I asked about that early on. Since the TS is considering using jewelry that she has on and batteries she's finding laying about, presumably she's not too restrained and the rope that needs cutting is serving some other unstated purpose and not being used to tie her to a chair with her hands bound behind her back.
 

jpanhalt

Joined Jan 18, 2008
11,087
Whether she's tied up or not isn't clear -- I asked about that early on. Since the TS is considering using jewelry that she has on and batteries she's finding laying about, presumably she's not too restrained and the rope that needs cutting is serving some other unstated purpose and not being used to tie her to a chair with her hands bound behind her back.
You're over analyzing it. Remember, this is a scene from MacGyver.
 

WBahn

Joined Mar 31, 2012
30,045
You're over analyzing it. Remember, this is a scene from MacGyver.
Where are you getting that this is a scene from MacGyver?

This is a scene that the TS is trying to write. His goal is to be realistic, regardless of whether or not he appreciates how unrealistic MacGyver was.
 

Thread Starter

Triple9Nickel

Joined May 31, 2020
28
A 9 V battery won't do it, the internal resistance is too high. The car battery is a good choice, you just need to find the right size wire. Can your heroine manage to find an old toaster lying around that she can rip apart? They have pretty much just the wire you're looking for.

What kind of rope is this? How thick? If it's too thick you might have to worry about it being able to carry the heat away from the contact site as fast is it is being supplied.
I still love MacGyver but I appreciate your professional perspective. So let's look at this as MacGyver done right.

I'm going to see if I can make the jewelry idea work. @MrChips suggested a 6V lantern battery so I will test that.

A few people have suggested the toaster solution (or a space heater), what specific wire am I looking to get from it? Is this for the heat blade portion of the design, or something else?
 

MrChips

Joined Oct 2, 2009
30,795
You are looking for a piece of wire that has some resistance as opposed to an ordinary piece of wire that has very low resistance. That is what the heater coil in the toaster or space heater does. I thought of the idea of breaking a light bulb and using the bulb filament. But then why not use the broken glass to cut the rope. @WBahn said it first. I presume you want to use the fact that she is an electrical engineer and want to add science/engineering intrigue into the plot.
 

Janis59

Joined Aug 21, 2017
1,849
Then use the old-fashioned table lamp what gangsters forgot to switch out. And heroine get near the bulb thus the hot bulb glass is melting the ropes.

Or let she extract for her mobile phone (what was stomped by feet of evildoers and not function anymore) the battery and apply to the pin-needle. Yet how to keep it pushed when the red-hot. Okay, she is heroically sacrificing her nail-lack and got two burns yet freedom. Public like a bit of blood in movies.

Next scenario: Evildoer throws down the cigarette and goes off while the roughly empty cognac bottle is on the table. Heroine manages to wet rope into last droplets of spiritus and then cigaret last sparkle blows the spirit flame, thus the rope are burning off. Heroine tears off in the pain, but freedom costs so. Watchers crushes the chairs from exaltation.

Or hi-tec scenario for surprise collectioneers: modern day CoViD antiviral lamp is left on the table, because the Evildoer was very obsessed with avoid from the pandemy, thus the Heroine stands so near the lamp that after a hour those plastics overpolymerisates, become brittle and cracks until become free.

Or another version: Heroine see the acetic essence on the kitcken, so she manage to fall down the bottle and crush, then floor is wet of the acid. She lies into acid with rope, and as the acetic is solvent for kapron, the rope is dissolute. Let the end would be more dramatic, she would feel the skin-burn, so she finds in the kitchen shelves the kitchen soda and powderize to the skin. Then obvious foam are growing out of reaction so everyone understands how dangerous situation really was.

No, a "russian version" of Heroine heroe-deeds would implement the russian mafia most belowed inquisition tool - the switched-on soldering hammer. Evildoer (with mister putin face) pushes it into her boyfriend ass and demand to tell where the gold is hidden. No, not a gold, but drugs, or both, drugs and gold. And when he before death is telling them where, they hurry left away the poor heroine alone, so she manages to get the still hot soldering hammer out of the boyfriend dead body and successfully melt-cut her ropes by it. When she call the 911 from unhabited island where all the happens take a place, 911 says the life of her friend is still possible to save if to smear the sea-thorn berry extract onto skinburns. That berries really grow there at dunes so the friend is getting alive, but he is damn upset because of the extraconscious pain of acid in those berries that tries to kill Heroine again. She is escaping but boyfriend is running over the Evildoer who not found the gold, sory - drugs. So the kickboxing a la Bruce Lee style may go on for one more hour. And then the pain have calm down and Hero comes to Heroine to say pardon. Both are falling in sweet kiss on the panorama of tropic paradise within the sunset.

And last but not least way if she is radio engineer, she found the spiral type of plasma lamp (CCFL) so she manage to beat the glass but all the glass is falling down the abyss, so she cannot use it like knife. Then she remember the CCFL has a resonant output in current stabilized regime so if she makes a short-circuit, the sparkle will be very bold. So she use the bulb like a plasma torch keeping by the lamp body and cut her ropes. When the Evildoer is back not finding his gold and drugs, the last use is to tick him with this CCFL lamp what generates few kilovolts in the no-load regime, thus the Evildoer dribble in tremor until his unclean spirit is coming out off the nose in outlook of dirty spook rolled into dirty bed-cover.
 
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Thread Starter

Triple9Nickel

Joined May 31, 2020
28
You're over analyzing it. Remember, this is a scene from MacGyver.
This is not for MacGyver, I don't write for MacGyver. It's a new show.
What if the bad guys decide to use Manila rope or sisal rope? That's what was used in old movies and still is for hanging.

Maybe a little battery acid and high nitrogen fertilizer will "cut" it.
Okay, I can make the rope any kind, or any thickness. Battery acid might burn their hands, but how would fertilizer cut the rope? there could be fertilizer if they were in a barn.
 

Thread Starter

Triple9Nickel

Joined May 31, 2020
28
@WBahn @Janis59 @jpanhalt @MisterBill2 Thank you all for the suggestions, this is incredibly helpful and enlightening.

The heroine is an electrical engineer, so she would be "looking for alternatives" as she is going to die soon if she does not escape. Her hands are tied up, but she can get things into her hand, and there are other tied up people so they could pass limited things to each other using feet or teeth.

@MisterBill2 I'm intrigued by this hairpin only idea, meaning no conducting wire is necessary. Could also work with a steel wire earring I suppose. It would probably be far too hot to touch though if it's also cutting the rope.

@MrChips @WBahn If we did the lightbulb idea, would it still need to be plugged in, and isn't that a raging death hazard if we smash the glass around it? Does the filament stay lit/attached if you smash the glass?
 

MrChips

Joined Oct 2, 2009
30,795
I think we are contemplating not using AC Line power. We are in an old barn with no live power.

Maybe there is a lantern flashlight laying around. These are not uncommon in a rural setting.
She takes the hood off and breaks the flashbulb. Then uses the hot filament to cut the rope.


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Thread Starter

Triple9Nickel

Joined May 31, 2020
28
I think we are contemplating not using AC Line power. We are in an old barn with no live power.

Maybe there is a lantern flashlight laying around. These are not uncommon in a rural setting.
She takes the hood off and breaks the flashbulb. Then uses the hot filament to cut the rope.
Yes that makes sense. Definitely no AC power.

I see, so you mean we break the glass, the lamp is still powered by the battery, and she has a safe handle to maneuver it. That's not a bad idea.
 

atferrari

Joined Jan 6, 2004
4,768
However, practically, if the count of cutted ropes are below the 100, I would never make an any machine. But sitting with the sharp knife on the taburette and cutting cutting cutting. Better alternatives are flex-machine (aka angle grinder) or steel cutting giljottine. Then take a lighter of candle and make the ends burning job.
What if the bad guys decide to use Manila rope or sisal rope? That's what was used in old movies and still is for hanging.
Maybe a little battery acid and high nitrogen fertilizer will "cut" it.
@Triple9Nickel

Worked my whole life in an environment where ropes are of daily use to lift and secure things even big vessels. Personally I even did splices and other traditional labors with them.

In the past, hemp was the rule; hard to handle (heavy and rigid) is a rough material which becomes easily hardened when wet. Do not allow the bad guys to tie your heroine with that! She will hate you for the rest of the story. And maybe even after... She will have to burn herself to burn the ropes. Bad business.

Fibers, light as they are, even the old nylon or polyethylene, dacron, perlon, etc. are really strong (that's why they are used for that, after all). Just for you to understand what she could face please note that what this guy has to use for cutting the rope. Add to that if your bad guys are good professionals would tie her with the arms on her back. Expect a mess.

My suggestion: provide the bad guys (police also use them) with enough zip ties and convince her to carry a (metallic) big size nail file, starting in Chapter 4, just in case plans change without notice.

Otherwise...
 
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