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See this?

enter image description here

  1. I want it melted into a puddle of glowing metal, since, from my admittedly-narrow perspective, it's the only way to be sure.

  2. I want it melted with something human-portable, so that I can bring the weapon to the threat - potentially over terrain that a land vehicle cannot traverse, or underground where my limited supply of functional post-nuclear war aircraft can't be used to reach - rather than having to lure the latter to the former.

  3. I want this melting done as quickly as possible, given the risks inherent to letting something like a Terminator (a) know you exist while (b) being not destroyed.

What manner of weapon or implement do I use for this?

Assume that we're dealing with the T-800 model or one of its derivatives here. Unfortunately, other models have proven quite adept at melting themselves into puddles, as well as reversing that process; R&D in regards to counteracting this is ongoing.

Apparently, a T-800 is 400 to 640 pounds; let's assume that all of that is made out of coltan, a substance which has been mentioned as being what they're made out of.

Also, assume that we're working with modern technology. No phased plasma rifles in the 40-watt range.

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    $\begingroup$ Asking directly about third-party works is not permitted on Worldbuilding.SE. You can still use the T-800 as an illustration but you should specify exactly all the relevant facts about the robot (e.g. what it is made of), without asking people to interpret James Cameron's work in order to answer the query. $\endgroup$
    – KeizerHarm
    Commented Jan 3, 2022 at 10:15
  • $\begingroup$ There is an episode of Dr. Who where they use a microwave system to massively heat a dalek and melt it's shell (not dalekanium, so...) Not sure how a real system would work. No details, so not a full answer. Free to use if someone knows. $\endgroup$
    – DWKraus
    Commented Jan 3, 2022 at 15:14
  • $\begingroup$ It would help to know just what your T-800 equivalent is made from and how much it weighs. $\endgroup$
    – Monty Wild
    Commented Jan 3, 2022 at 15:46
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    $\begingroup$ @KeizerHarm Edited; assume that they're 400 to 640 pounds of coltan each. $\endgroup$
    – KEY_ABRADE
    Commented Jan 3, 2022 at 18:44
  • $\begingroup$ If there were a practical, modern, human-portable weapon capable of this sort of destruction, it would be used as eg. an anti-tank weapon. There isn't. Your premise is strictly scifi. $\endgroup$ Commented Jan 4, 2022 at 10:23

6 Answers 6

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Thermite

Thermite (/ˈθɜːrmaɪt/) is a pyrotechnic composition of metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic reduction-oxidation (redox) reaction. Most varieties are not explosive, but can create brief bursts of heat and high temperature in a small area. Its form of action is similar to that of other fuel-oxidizer mixtures, such as black powder.

Thermites have diverse compositions. Fuels include aluminum, magnesium, titanium, zinc, silicon, and boron. Aluminum is common because of its high boiling point and low cost. Oxidizers include bismuth(III) oxide, boron(III) oxide, silicon(IV) oxide, chromium(III) oxide, manganese(IV) oxide, iron(III) oxide, iron(II,III) oxide, copper(II) oxide, and lead(II,IV) oxide.

The most common composition is iron thermite. The oxidizer used is usually either iron(III) oxide or iron(II,III) oxide. The former produces more heat. The latter is easier to ignite, likely due to the crystal structure of the oxide. Addition of copper or manganese oxides can significantly improve the ease of ignition. The density of prepared thermite is often as low as 0.7 g/cm3. This, in turn, results in relatively poor energy density (about 3 kJ/cm3), rapid burn times, and spray of molten iron due to the expansion of trapped air. Thermite can be pressed to densities as high as 4.9 g/cm3 (almost 16 kJ/cm3) with slow burning speeds (about 1 cm/s). Pressed thermite has higher melting power, i.e. it can melt a steel cup where a low-density thermite would fail.[25] Iron thermite with or without additives can be pressed into cutting devices that have heat-resistant casing and a nozzle.[26] Oxygen balanced iron thermite 2Al + Fe2O3 has theoretical maximum density of 4.175 g/cm3 an adiabatic burn temperature of 3135 K or 2862 °C or 5183 °F (with phase transitions included, limited by iron, which boils at 3135 K).

Thermite reactions have many uses. It is not an explosive; instead, it operates by exposing a very small area to extremely high temperatures. Intense heat focused on a small spot can be used to cut through metal or weld metal components together both by melting metal from the components, and by injecting molten metal from the thermite reaction itself.

Thermite hand grenades and charges are typically used by armed forces in both an antimateriel role and in the partial destruction of equipment; the latter being common when time is not available for safer or more thorough methods.

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    $\begingroup$ @KEY_ABRADE since it comes in grenade form, any form of RPG or grenade launcher with a sticky grenade would work right? Since the movies (sorry, historical instruction video's), have shown that they can already be dispersed with explosives you might also "just" use a rocketlauncher to make it rain terminator pieces and then apply thermite paste to the pieces. $\endgroup$
    – Demigan
    Commented Jan 3, 2022 at 9:05
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    $\begingroup$ Enough thermite to do the job weighs too much to be man portable. And it's not hot enough, anyway. $\endgroup$ Commented Jan 4, 2022 at 2:38
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    $\begingroup$ My crude (and possibly erroneous) napkin calculation of the heat quantities involved seems to indicate that 1 weight-unit of thermite would emit enough heat to push to melting temperature and melt ~5 weight-units of coltan. So if 100% of heat gets absorbed by the terminator, the "grenade" would have to be ~100 pounds; and if there's any inefficiency, you need more thermite. $\endgroup$
    – Peteris
    Commented Jan 4, 2022 at 5:40
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    $\begingroup$ @L.Dutch That depends. Which is the point of my critique of this answer. "It depends" with thermite, too. $\endgroup$
    – hyde
    Commented Jan 4, 2022 at 9:49
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    $\begingroup$ RussG's answer, mentions that coltan melts at 5500F, and this answer says thermite burns at 5183F, so that's not enough to melt the Terminator into slag. Also, thermite is slow to burn. I've seen it burn through an engine block, but it took a couple minutes to do it. That's a couple minutes more than a Terminator needs to kill you. Even this answer says it's slow burning and affects small areas. It took 1000 lbs of thermite just to kind of cut a car in half, not even melt through the whole (thin) roof. youtube.com/watch?v=lIpa1K51os4 $\endgroup$ Commented Jan 4, 2022 at 16:30
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A B54 SADM.

This 32kg man-portable nuclear weapon has a yield of 10 to 1000 tons of TNT, or 41.84 to 4184 GJ.

This is sufficient energy to reduce 64.77 to 6477 metric tons of steel to molten slag, way in excess of any reasonable estimate of the mass of a Terminator.

Such a small atomic weapon could be carried to any ambush point by a single person, will operate underwater, and could be triggered manually, on a timer, or by a booby-trap trigger.

A close-range atomic blast, even as small as this, would likely vaporize a Terminator, much less melt one... and this weapon should do the job in a millisecond or less. The terminator might have time to recognise the threat, but it won't be able to move fast enough to make any difference whatsoever.

Nuking the Terminator is the only way to be sure.

Edit

In response to the OP's edit stating that a T-800 weighs up to 640lb, or 290kg, we should be able to estimate how much an atomic weapon should be able to increase its temperature.

If a Terminator is exposed to 5% of a close-ranged blast, not unreasonable considering that an atomic weapon emits its energy in all directions, it would be subjected to 2.09 to 209 GJ of energy.

Now, assuming that the Terminator is made from steel alloy (I don't believe that a Terminator is made only from coltan, and steel has a higher specific heat) with a specific heat of 420 J/(kg°C), a heat of fusion of 268 kJ/kg, a melting point of 1540°C, a heat of vaporisation of 6090 kj/kg and a boiling point of 2870°C.

Assuming that the Terminator starts at a temperature of 37°C, normal human body temperature, to increase its temperature to 1540°C takes 183 MJ. From there, to melt the steel takes a further 78 MJ. Once melted, to raise its temperature to boiling point takes a further 162 MJ, and to vaporise it would take 1.766 GJ, for a total energy requirement to vaporize of 2.189 GJ.

At the lowest yield estimate for this weapon, the Terminator would be substantially vaporized, and the remainder would be splattered as white-hot liquid metal across the blast area. At the highest yield estimate, it would be turned into plasma in its entirety.

That's a worst-case estimate. Should the Terminator be made from materials with a lower specific heat and lower heats of fusion and vaporisation, it would likely be completely vaporized. If it was made from materials with higher constant values, it would still likely be completely melted and at least partially vaporized, and no doubt splattered across the remaining landscape.

Unfortunately, the SADM fails the OP's criteria in one way: there isn't likely to be a puddle of molten metal at all... at most there will be finely divided particles of molten metal which will rapidly oxidize in the surrounding super-heated air.

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    $\begingroup$ @JohnDvorak They can shoot it, but this stretches the limits of man-portable. You'd need to be ultra buff, or have a two man team to man the Davy Crockett: en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device) $\endgroup$
    – Dragongeek
    Commented Jan 3, 2022 at 14:58
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    $\begingroup$ Buff isn't a problem, just grab someone like Arn... wait. That's the guy we're fighting against. Drat. $\endgroup$ Commented Jan 3, 2022 at 15:01
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    $\begingroup$ @Dragongeek Okay... but I wasn't referring to the Davy Crockett in my answer... just a B54 SADM which weighs 32kg total, and is portable by 1 person. It may be a demolition munition, but there's no reason why it couldn't be used to arm a trap. $\endgroup$
    – Monty Wild
    Commented Jan 3, 2022 at 15:44
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    $\begingroup$ @JustinThymetheSecond You might be surprised at just how hard nukes can be to detect. With just a little shielding, they have practically no radiation signature at all. It takes stuff like neutron activation or gradiometry to detect them reliably, and a Terminator isn't about to do either. $\endgroup$
    – Monty Wild
    Commented Jan 3, 2022 at 16:01
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    $\begingroup$ @JustinThymetheSecond Well made shielding is generally pretty easy and often good enough to completely hide any radioactivity. There are dozens of lost nukes (and RTGs, and other similar things) in the world that have remained unfound simply because we have no way to track them down short of an extra-fine grid search in the areas they are presumed to be in. $\endgroup$ Commented Jan 3, 2022 at 16:51
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Coltan melts around 5,500 degrees, but modern plasma torches reach temperatures of about 25,000 degrees.

Plasma Rifles in the 40 watt range aren't available, but plasma torches and cutters definitely are.

These guys have even made a retractable plasma based lightsaber that burns at 4,000 degrees, which doesn't quite melt Coltan (5500 F)

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

https://www.youtube.com/watch?v=xC6J4T_hUKg

Given that these guys are amateurs without any kind of actual funding beyond their Patreon, it seems like someone motivated to kill Terminators would be able to iterate on this until they end up with one capable of taking Arnie down.

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    $\begingroup$ The problem with plasma torches is not the temperature, but the quantity of heat output - it takes an immense amount of heat (and thus fuel) to heat and melt so much coltan, and it's not clear that an oversized plasma torch (and its fuel) sufficient for that would still be man-portable. $\endgroup$
    – Peteris
    Commented Jan 4, 2022 at 5:32
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It can't be done. It can be done.

First, let's consider chemical devices. You've got say 500 pounds that need to be heated to 4,500 degrees. What can we do to deliver that kind of heat?

Beam weapons. Lasers, plasma weapons and the like.

First, lasers. Most of the power that is fed to a laser appears as heat in the laser, not into the beam. If your laser is 50% efficient (and AFIAK none are) if it can heat the robot to 4,500 degrees it will also heat 500 pounds worth of laser to 4,500 degrees--and you'll need a lot more weight for it's powerpack. Thus the laser must be a lot more than 500 pounds--that's not man portable. (And that assumes it's all absorbed--much of it won't be.)

Plasma. I'm not sure on efficiencies here, but you've got a big range problem--plasma doesn't go very far. An awful lot of the energy you are pumping into the target will bounce back, your gun better be a lot tougher than the terminator. If you've got that sort of tech just grapple it!

Plan B: Thermal lances and the like. These are pretty much a chemical parallel to the plasma weapon--and the same objections apply.

Ok, we have to go up the ladder. SADMs have already been mentioned. Now we finally have enough energy in a man-portable package--but that doesn't mean we can actually get the energy into the terminator. Let's lure the terminator across a nuclear land mine--boom, there is a tremendous flash and a ball of extremely hot plasma. But look at what happens--we've probably all seen videos of what happens when objects are exposed to the flash of a nuke--the surface is heated. Only the surface, though--the paint is vaporized or even converted to plasma, but the wall behind remains. Newton's Third law applies--we vaporize a bit of the terminator and throw the rest out very, very fast. It quickly departs the plasma ball--we have substantial damage to any spot facing the bomb and some damage all around, but the main part is not melted. Look up Project Orion--objects can be quite close to a nuclear detonation without absorbing any major heating.

If the only way to kill it is to melt it I think the only hope humanity would have would be to catch it in a mine with some big booms and I wouldn't want to count on that melting the whole thing. Note that the movie approach does not work, that crucible of molten metal won't be hot enough to melt it.

(On the other hand, it might not be necessary to kill it. Put a large h-bomb in a well, lure it across the opening. Throwing it above escape velocity won't be a problem, the hard part is throwing it hard enough that it gets through the atmosphere still going fast enough. It has no propulsion system, it can't return.)

Update: There's an outside-the-box way to destroy it, but we don't get a puddle. I recently found this discussion of the fate of the Pascal B cap and this provides a means of vaporizing it. Lure it across a substantial nuclear mine. It's going to meet the same fate as the cap on the Pascal B test--vaporized by the atmosphere.

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    $\begingroup$ Actually, atomic weapons irradiate the surrounding area with most of the energy that they emit before the thermal expansion of the surrounding air begins. By the time that the atomic reaction has finished and the heated air begins to move, a human-sized object will have absorbed enough energy to vaporize if it is close enough to the atomic device. This would include a Terminator, most likely. Additionally, a Terminator is not a solid, spherical chunk of metal, it is a relatively sparse, distributed structure with a high surface area to volume ratio. $\endgroup$
    – Monty Wild
    Commented Jan 4, 2022 at 15:22
  • $\begingroup$ @MontyWild While the energy is certainly sufficient to vaporize the terminator the problem is it won't have time to penetrate. The surface gets burned off but surface damage doesn't stop them. Dumping that kind of energy onto the surface doesn't get it inside. $\endgroup$ Commented Jan 5, 2022 at 4:18
  • $\begingroup$ A terminator's endoskeleton is mostly surface area. It's not very compact. At close range, I disagree, it would be vaporised, or at least slagged down and splattered. $\endgroup$
    – Monty Wild
    Commented Jan 5, 2022 at 12:06
  • $\begingroup$ @MontyWild It comes down to how thick it is. I would expect minimal ablation, same as we see with the thermal pulse against a building--the material on the surface that vaporizes protects what's underneath for a bit. $\endgroup$ Commented Jan 5, 2022 at 16:12
  • $\begingroup$ There is only 1 way to find out. We must build a Terminator and nuke it. It's the only way to know before Terminators take over. Science. $\endgroup$
    – c1moore
    Commented Jan 5, 2022 at 22:20
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If the goal is to melt the target, using current technological ability, the only way to produce sufficient heat in a man-portable way would be a fission heating device, taking inspiration from Corium material (the melted lava-like alloy formed in a nuclear reactor meltdown).

The maximum temperature reached by typical nuclear reactor contents in a meltdown is said to be up to 2800°C in the above linked Wikipedia article. Pure Tantalum has melting point of 2996°C. However, the Terminator endoskeleton is an alloy, so it will have lower melting point. Also, a nuclear material mix specifically designed to reach high heat output with self-limiting nuclear chain reaction should easily reach high enough temperatures to melt even pure Tantalum.

We want isotopes which do not boil away at too low temperature, and which have low enough critical mass so that the weapon is man-portable, and which have reasonable half-life so they are not overtly radioactive without a chain reaction. Therefore isotopes of interest, taken from this Wikipedia article, include at least these:

Isotope         Half-life, years    Critical Mass, kg   Boiling point

Uranium-233     159200              15 kg               4131 °C
Neptunium-236   154000              7 kg                3902 °C
Plutonium-238   87                  9-10 kg             3232 °C
Plutonium-239   24110               10                  "
Plutonium-241   14                  12                  "

Using these, and ignoring any environmental and safety regulations on testing, it should be trivial to design a special Corium cocktail, which

  • Is safely sub-critical in a hollow sphere or cylinder.
  • Is super-critical (has exponentially accelerating chain reaction) when collapsed into a solid mass.
  • Becomes sub-critical when it starts to boil, so that the chain reaction immediately stops when bubbles form in the hottest part of the mass (the center), and as a result the mass remains in nice, toasty temperature of about 3200°C...3500°C
  • Can have a chain reaction with mass under, say, 20 kg.

Construction of the warhead should be so, that the Corium cocktail is in a form of two hemispheres, or possibly even several separated disks, staying safely sub-critical. When fired from a recoilless rifle, these parts get smashed together into a sphere, which promptly begins a chain reaction and basically melts almost immediately (like, in 100 ms, as designed), but does not explode or evaporate because the chain reaction ends when any material starts to boil, as explained above.

When fired successfully, and melting on the way to the target, the now molten sphere of highly radioactive material at above 3000°C gets splashed onto the target, knocking it down with kinetic energy and starting to melt it. The sheer amount of radiation should also mess with its electronics, at the very least frying its visual sensors.

Now the splash will also stop the chain reaction, because the Corium cocktail is going to become too dispersed. Solution to this is simple. You need several attackers firing at the target when it is knocked down, so it stays down and is thoroughly covered in the Corium cocktail, which will agressively remain near boiling point. The puddle will likely stay molten months, if not years, slowly melting its way through the ground.

As for the delivery system, for example the US Javelin has warhead weight of 9.4 kilograms, while weight of weapon when ready to fire is 22.3 kg. This is a good starting point, and by removing guidance and reducing range and velocity, and increasing total weight a bit it should be possible to reach warhead weight of around 15 kilograms.

The obvious drawback is, this requires a team. Also, due to radiation released, using this weapon is likely a suicide mission, unless you add some remote firing ability. But hey, you gotta do what you gotta do.


If you come up with a way to restrain the target (some kind of net?), then you could tie it down and place a crate of this special Corium cocktail on top of it, and then trigger the reaction by just removing supports keeping parts of the material separate and subcritical. Melting commences, and no one else has to die.

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  • $\begingroup$ Interesting answer, but wouldn't a Corium cocktail be so horrendously passively radioactive that it would be suicide to transport in any case? $\endgroup$
    – Magisch
    Commented Jan 6, 2022 at 15:17
  • $\begingroup$ @Magisch As long as chain reaction is not happening, it is not horrendously radioactive, and could be made safe with very thin layer of lead. Plutonium-241 undergoes beta decay (ejects electron), Plutonium-238 undergoes alpha decay (ejects a Helium nucleus), so they aren't immediately very dangerous, and their decay products have longer half lives. I might edit the answer to cover this later, but it needs a bit more research, so I'll leave this as a comment for now. $\endgroup$
    – hyde
    Commented Jan 7, 2022 at 12:09
  • $\begingroup$ In general, radioactive materials are not very dangerous to humans because of their radiation, unless particles get lodged inside body, such as Cesium-137 accumulating in Thyroid, or Radium gas inside the lungs decaying into a non-gaseous element which is also radioactive and will stay in the lungs. $\endgroup$
    – hyde
    Commented Jan 7, 2022 at 12:16
  • $\begingroup$ ...and actually, Aluminum and plastic are good shielding against beta radiation mentioned above, so actually lead is not needed. Also, these short-lived isotopes would probably not be used in the cocktail, at least not in large quantities. $\endgroup$
    – hyde
    Commented Jan 7, 2022 at 12:27
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The obvious solution is to turn its own energy source against it. As we know, Terminators and the like contain compact, extremely high-wattage power sources.

A device which causes this to become unstable, either by physical means (induced vibration, hyper-intense shockwave) or something more subtle (electronic override, hacking, EMP) causes it to overload and dump all its energy at once, causing thermal runaway and melting the droid on the spot.

Job done, and it can be a small enough to fit in your pocket. Just make sure its charged before you run into Arnie.

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