How to Make a Faraday Cage for less than $5

Hey everyone,

With all this talk about EMPs and how some or all electronics can be fried in an instant when it happens, it’s time to see what we can actually do to protect our devices. The most popular solution you will find to survive an EMP (apart from learning to actually live without electricity) is to make a Faraday cage, that is to say an enclosure that would protect your devices from this electromagnetic pulse.

Although the EMP literature is scarce, and often contradictory, I found a “recipe” for a Faraday cage that should withhold both types of EMPs, whether natural or man-made. Based on my own research, I’m pretty sure this will work better than a microwave, a galvanized trash can, or some of the other solutions you can find online.

The idea is simple: wrap your devices inside a thick layer of aluminum foil, the thicker the better, after they’ve been covered by a layer of insulating material to avoid your devices from touching the conductive material.

Aluminum foil is cheap, you can find cardboard around the house for free, duct tape and packaging tape are also dirt-cheap, so you can make a cheap Faraday cage for less than $5. Now you will spend more than $5 for these supplies, but keep in mind you’ll be able to make several cages for this amount of money.

The idea behind a Faraday cage is that right before this electric surge reaches your devices, it will hit the conductive material box instead (made in our case of aluminum foil), flow around it and leave the contents of the cage intact.

The electric current always takes the path of least resistance, so it will go through the conductive layer and not inside it, so long as inside you have an insulating layer that will ensure your phone or flashlight is NOT in direct contact with the conductive layer.

Depending on the intensity of the EMP and the frequency spectrum, the first conductive layer might not be strong enough to absorb the whole pulse, which is why we need a conductive layer that’s as thick as possible.

The conductive layer should NOT have any holes in it. Fully enclosed Faraday cages generally do a better job at dissipating electric current than mesh cages (source).

How to make Faraday Box Step-by-step

So step one, get some heavy-duty aluminum foil, preferably one that’s as thick as possible.

step 1 aluminum foil

Step 2, get a cardboard box. You will need several of different sizes, actually. Keep in mind you won’t be using these items until after the EMP, you can’t take them out and put them back in, as it will compromise the integrity of the layers.

step 2 cardboard box

Step 3: Feel free to add additional insulation inside the box, such as bubble wrap. This will ensure the items are shock-proof.

step 3 bubble wrap

Step 4: wrap your device with the bubble wrap, then put it into the cardboard box and seal it with duct tape or something similar.

step 4 sealing cardboard box

Make sure you don’t leave any open spaces in your box, the cardboard should overlap in all the places it can be open and, needless to say, it shouldn’t have any holes in it.

Step 5 is to wrap the cardboard box in aluminum foil. Feel free to wrap it several times, to make the layer thicker more effective. The box should look like this:

step 5 aluminum foil

That’s about it. A cheap an easy way of making a Faraday cage that should keep your devices safe from an EMP blast. The more layers you add, the safer it will be, but then you sacrifice portability. You may want to make one for your bug out bag and one to keep inside your safe room or your black out box.

Are there any Faraday cage variations you think will make it even safer? Let us know in the comments below.

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