How to make a Faraday Cage

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How to make a Faraday Cage

When you start talking doomsday scenarios, one that frequently pops up (at least with the team here at APE Surevival) is the EMP. Designed as a weapon to completely disable electronics using an Electromagnetic Pulse, the wave from such a blast is potentially powerful enough to wipe out electronic devices across an entire continent. Luckily, an event at this magnitude has yet to happen, but it pays to be prepared. In the aftermath of an EMP life as we know it would completely change. It's rather romantic to consider a simpler time where we all go back to living off the land, but a disaster at this scale would set us humans back even further. For the most part, we no longer have the skills and even raw materials to survive off the grid, which leaves us with only one option. Protecting our electronics from such a blast. This is where the Faraday cage comes in. Invented by Michael Faraday in the mid-1800s, a Faraday cage is designed to mitigate the effects of an electromagnetic pulse, shielding whatever electronics you have stored inside. At the most basic level, it's simply a box that has an electrically conductive outer layer. It works because this outer layer reflects and absorbs incoming energy, building an opposing energy field that safeguards what you've got stored inside. Like your set of walkie talkies, a solar charging kit, or a laptop. And building one isn't altogether difficult. The trick behind a Faraday cage relies on the tendency for energy to flow over the skin of a conductor, which means that you can wrap a box in multiple layers of heavy-duty aluminum foil and the surface area will absorb an EMP charge, even though it seems to be only a thin covering. You can use any type of metal for this, but aluminum foil is readily available and cost effective. Today, we're going to use a metal garbage can to make an insulated Faraday cage.

You will need:

  • 1 metal garbage can
  • 5-10 rolls of heavy-duty aluminum foil
  • 1-2 rolls of saran wrap (depending on the size of the items you want to shield)
  • Cloth to wrap each individual item (I repurposed a few old t-shirts)
  • An assortment of cardboard boxes of various size
  • The electronics you want to protect
In my Faraday cage I've stored a set of four walkie talkies, an old Kindle loaded with reference books, a solar powered clock radio, a portable solar charging station, a mp3 player loaded with tunes, a couple of LED torches with the batteries out, a notebook PC, and a small HAM radio kit. You're not going to be able to get to these items very easily, so make sure you're not protecting electronics you're going to miss. First, protect each item by wrapping it in a piece of cloth. This helps to stop it getting damaged if you're moving your Faraday cage around, and will stop any hard edges from breaking through the foil. Over the top, use saran wrap to seal each item, then cover it in at least 3-4 layers of foil. Do this gently, making sure there are no holes or rips as you cover each layer. Place every item inside a cardboard box, and seal it shut. Over the top, wrap another 3-4 layers of foil, making sure that none of the foil covering the box touches any of the items inside. It shouldn't, but this is an important point for protection. Line the inside of the garbage can with cardboard, so there are no places where your stored items inside can touch the metal, and place each of the sealed boxes inside. Ensure there are no holes in the garbage can and that the lid fits tightly, and once it's sealed you're now safeguarded against an EMP attack. You've now got three layers of protection over your electronic items, which is more than enough to protect them from an EMP. There's been some discussion in the team at APE Survival on the effectiveness of ‘grounding’ our Faraday cages, but in field testing it was discovered that the charges inside our homemade Faraday cages hardly differed when they were grounded. What it does protect from is the cage itself becoming charged, and perhaps re-radiating after the event. Essentially, you don't need to ground your Faraday cage to protect what's in it, but you might want to for your own peace of mind. Heck, you can even build a Faraday shielded room (or closet) using these same principles, though it might be a little overkill unless you've got a significant amount of electronics that warrant protection. Line every wall, the roof and the floor with heavy-duty aluminum foil, overlapping each layer and taping up the seams. Nothing can penetrate the room, so you will also need to cover the windows, light switches and electrical outlets, and then line the floor with cardboard or plywood to ensure you can walk on it without tearing the foil. Personally I'd convert a large closet before I dedicated an entire room in my house to electronic protection, but I also don't have a huge amount of items to protect. The key to surviving a SHTF event is to plan ahead, and make sure what you've prepared is done right the first time. With a Faraday cage it's doubly important so take your time to build it properly and ensure you've got what you need to survive whatever comes. Do a sloppy job and you'll find everything you thought was protected is now just as broken as everything else in the aftermath of an EMP, as there really is no second chances.