What is a Faraday Cage? In a nutshell, a Faraday Cage is s container that protects sensitive electronics from an Electromagnetic pulse generated from a nuclear detonation high in the atmosphere, or from a massive solar flare. A massive EMP will render anything that uses chips, resistors etc. (basically all electronics) useless ... forever. They will be "fried". This article will instruct you on How To Build A Faraday Cage for about $50 bucks that will protect your valuable electronics and batteries.
A simplistic explanation of the construction of a Faraday Cage is: any metal box, or cage (it doesn't have to be solid) that completely surrounds the contents with a "metal shield", including the top and the bottom. The EMP will pass over and around the Faraday Cage rather than through it, thus protecting any electronic (and batteries) that have been placed inside the cage. Your microwave oven is actually a Faraday Cage. If you look closely at the glass door, you'll see a mesh embedded within the glass. That same mesh is also between the inner and outer skin. If there was no metal mesh, the microwaves would burn your face when you peeked into the oven to see if your burrito was done.
You can spend a kings ransom for a custom built Faraday Cage, but it's not necessary.
If you've researched Faraday Cages on the Internet you've probably received a lot of different information. Why? Simple. We (the world) has never experienced a massive EMP and regardless of what anyone on the Internet says, no one, including me, can say with absolute certainty that a home-made Faraday Cage will work. In theory it should. But at the end of the day, it's still just a theory. However, for 50 bucks, if there's an EMP and the Faraday Cage you built doesn't work, you really haven't lost anything. And if it does work, then you've retained a portion of the 21st century while your neighbors are living back in the stone age.
Here's how to make a double Faraday Cage (just to play it safe) for about $50 bucks, that will (in theory) protect all of your sensitive electronics and keep you and yours out of the 19th Century.
Every item necessary to build a Faraday Cage, (or a double Faraday Cage), is available at Home Depot. For about $30 bucks you can purchase a 30 gallon galvanized steel garbage can (Make sure the lid fits tightly to the can), about 6 feet of #14 solid copper grounding wire, a 1/4" x 3/4" brass bolt, 2 washers, a lock washer, and a 3 prong electrical plug. These simple products will allow you to Build A Faraday Cage. However, since no one has ever tested this type of Faraday Cage against the effects of a massive solar flare (or an actual nuclear EMP) it makes sense to double the protection since you only get one shot at it. It would be tragic if the basic garbage can Faraday Cage wasn't sufficient. So ...if you want to build a DOUBLE FARADAY CAGE, for another $25 bucks, pick up one 36" x 5' roll of galvanized hardware cloth, and one roll of 24" x 5' hardware cloth.
Find some old cardboard boxes and take them home with you.
For tools you'll need a wire nippers, a drill, a screwdriver, a pliers, and some tape. Duct tape works well. That's it.
Let's Build A Faraday Cage. (instructions are for a double Faraday Cage)
If you're building the basic garbage can Faraday Cage, your first order of business, and regardless of what you've heard or read, is to provide a GROUND FOR THE FARADAY CAGE. Does it absolutely have to be grounded? Some say yes, some say no, but it's a very simple and inexpensive process to ground your Faraday Cage so why take the chance? Drill a hole in the bottom "lip" of the garbage can. Use a bit that is just less than the 1/4" bolt you purchased. Place a washer over the bolt, insert the bolt into the hole and screw the bolt into the hole from the INSIDE of the lip so that the threaded portion of the bolt is sticking out at the bottom of the can. Strip about one inch of insulation from the #14 gauge solid copper wire and loop it around the bolt right at the head, bending it with the pliers, while using the screwdriver to keep the bolt from turning. Place the other washer over the bolt, then the lock washer, and finally the wing-nut. Put the screwdriver into the bolt head and using the pliers, tighten the wing-nut as tight as it will go. (Make sure the wire doesn't "pop-off" the bolt. Next, strip about 1/2" of insulation off of the other end of the #14 copper wire and then take the cover off of the 3 prong plug-in. Attach the copper wire to the GREEN (GROUND) terminal only. Screw it down as tight as you can. Make certain the wire stays under the screw. Re-attach the plug cover and plug the 3 prong connector into any electrical outlet. Your Faraday Cage is now grounded through the electrical system of your home.
If you intend to build a Double Faraday Cage, (recommended) wear some light gloves, as the galvanized hardware cloth will have sharp points after cutting it. Remove the wire that keeps the hardware cloth in a roll. Cut that wire into 4" pieces. Now place the roll of hardware cloth inside the garbage can so the bottom of the roll rests on the bottom of the can. With a permanent marker, mark the edge of the mesh that comes to the very top of the garbage can. Take a nippers and nip the entire 5' of hardware cloth at that line. This next part is a pain in the butt if you don't have an assistant because the hardware cloth will automatically unroll into a circular position. Push it to the edges of the garbage can. There will be a slight over-lap of the mesh of about 4". You may have to make adjustments to ensure the mesh is touching, or that it's at least close to the entire inside circumference of the garbage can. Using the 4" wire ties, secure the two ends of the mesh together. One at the top, one at the bottom, one half way to the top, one in the middle, and one half way to the bottom, for a total of 5 ties.
Because the garbage can is a bit wider at the top than it is at the bottom, you'll end up with wire mesh sticking up above the top of the garbage can on one side. Simply fold it down until it's flush with the top of the can. But be careful ... those ends that you nipped off are wicked sharp.
Next, place the garbage can onto the second roll of hardware cloth. Using the permanent marker, and using the bottom of the can as a template, trace the bottom of the can onto the hardware cloth. Cut it out with the wire nippers. Insert the cut out portion into the bottom of the can. It will be larger than the bottom but that's OK, it will bend up as you push it to the bottom of the can, and automatically form a contiguous cage.
Do the same with the garbage can lid. Cut the circle for the lid and set it aside.
Using the cardboard box (one big one is good) and using the bottom of the can as a template, trace and cut-out a cardboard circle to insert into the bottom of the can. Put it directly over the hardware cloth screen at the bottom of the can. Next, measure the inside of the can from top to bottom. It'll be around 25.5". If you have a large cardboard box, flatten it out and cut it all the way across at whatever measurement you came up with. (25.5"?) Now put the cardboard, which will act as an insulator, (the contents should not touch the Faraday Cage mesh) inside the hardware cloth "cage" and push it out so it rests against the cage. Cut off any excess and duct tape it together.
As a further precaution, at minimal expense, place the items you intend to put into your Faraday Cage in Zip-Lock bags or wrap them in Saran Wrap. Next wrap them in 2 layers of heavy duty aluminum foil.
The total process will take about two hours ... maybe three if you brought home a six pack.
But regardless. You now have a Faraday Cage that should work every bit as good as the high priced ones available on the internet. Maybe better. Because you have a double Faraday Cage and in addition, the contents are foil lined.
It is said that an EMP can't or won't hurt batteries, but why take the chance? Your Faraday Cage can hold a LOT of gear. I put all of my batteries in this exact Faraday Cage. I also take the ACOG's and other electronics sights, off of my guns, NVD's, flashlights, and virtually everything else that is electronic and put them into the Faraday Cage. I also mark every wrapped item in the Faraday Cage for easy access if the need arises.
Make sure you include all batteries, including rechargeable batteries, watches that use batteries, LED flashlights (LED flashlights have a chip in them) and of course any other electronics you want (to be able to) use. The garbage can Faraday Cage can hold a lot of equipment.
Radio waves and cell phone signals operate on totally different frequencies than the pulse from an EMP. So don't worry if your cell phone still receives a signal inside the Faraday Cage, or your radio still plays. (They probably will.) The real test will come if (and when) a burst of energy from an EMP is produced. If the Faraday Cage worked, for about $50 bucks you'll still have access to whatever you placed inside your Faraday Cage. If it doesn't? ... No harm, no foul.
NOTE: As mentioned earlier, the microwave oven in your kitchen is actually a Faraday Cage. You can put your radios etc. in a Zip-Lock bag and keep them in the microwave if you want to, but it's a pain taking them in and out all the time. Or you could simply purchase a small, cheap microwave and use it for items you want to protect but that you use frequently.