There are a lot of reasons for wanting a lavamoat around your house, but not that many how-to videos explaining how to build one.
So we’re here to change that.
It’s actually pretty easy to make lava, at least in principle – the ingredients are just rocks and heat.
Lots of heat.
Most rocks melt at temperatures between 800and 1200 celsius, which is hotter than your oven, so you’ll need a gas or charcoal poweredforge, or an electric furnace.
It’s tempting to choose a kind of rock oreven metal or glass that melts at a lower temperature, but then it won’t glow as much:the intensity and color of the glow depends on how hot the lava is, and you definitelywant a lava moat that glows (preferably a nice bright orange-yellow color).
For this reason, we recommend only top qualityKeweenawan basalt obtained from the upper midwest.
One of the challenges in maintaining a glowinglava moat is that it’s literally radiating away its energy in the form of heat and light;this means you can’t simply melt your lava, pour it into your moat, and call it a day.
Your lava moat is going to need some kindof built-in heating apparatus to make up for the losses: a ceramic crucible with high temperatureelectric heating coils will work just fine.
And you’ll definitely want a good layerof insulation to keep heat from leaking into the ground – because you’re going to needa lot of heat! At the temperatures we’re working with, lava radiates roughly 100 kilowatts of heat per square meter (that’s equivalent to 1000100-watt lightbulbs per square meter – though you can’t fit 1000 100-watt light bulbsinto a square meter, if that gives you any sense of how intense lava is).
Anyway, electricity typically costs around10 cents per kilowatt hour, so each square meter of lava moat is going to cost you around$10 per hour.
This means that a lava moat a meter wide andenclosing an area roughly the size of a football field will cost $60, 000 per day to keep running.
If you don’t like the idea of being relianton somebody else to keep your lava moat home security system operational, you could insteadpower it with solar panels, or build your own power plant.
Each of these has its pros and cons: solarpower never needs fuel resupply shipments: the sun is going to keep burning for a while.
However, every square meter of lava moat requires2000 square meters of solar panels to keep it glowing day and night.
We don’t need to explain the security risksof putting your lava moat’s power source outside of the protection of the lava moat, so if you want a lava moat a meter wide powered entirely by solar panels inside of the moat, the math works out that the moat needs to surround an array of solar panels 8 kilometersacross.
Which is clearly absurd.
You can have a wider and yet more reasonable-sizedmoat if you instead build your own commercial scale power plant inside it – coal and nuclearpower plants produce enough energy to heat a lava moat 10 meters wide and encirclingan area 500 meters across – enough space to fit the power plant and your house inside! The downside is that (unless you build yourmoat on top of a coal or uranium deposit) you’ll need to bring in outside fuel, soyour lava moat won’t be entirely off-grid.
Perhaps the best off-grid option for poweringyour lava moat is simply to take inspiration from the source of lava itself: the earth’sown internal heat.
Assuming you don’t have access to an islandin a lava lake in an active volcano, the next best option is geothermal power: by choosingthe right location, a good geothermal power plant can heat a modest-sized lava moat that’sperfect for protecting a single family home.
I suppose you might also want to learn aboutprecisely how wide your lava moat should be to deter intruders, or how to cool your houseonce it’s successfully encircled by lava, or how to deal with all the noxious fumesgiven off by lava.
And for that, you need to check out the fulllava moat instructions available in the book, “How To” by Randall Munroe, which thisvideo is based on (and supported by).
How To is an absurd and entertaining self-helpguide full of ridiculous over-the-top advice about everything from how to dig a hole, tohow to be on time, to how to ski, to how to catch a drone.
You can find a how-to guide for how to obtaina copy of “How To” in the video description, and a big thanks to Randall and “How To”for supporting and inspiring this “How To” video.
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