DIY Farday Cage: EMP Protection

What is a Faraday cage?

It is a device that allows you to shield electronic devices from an EMP, which will destroy unprotected items such as radios, walkie-talkies, anything with circuitry.  Simply it absorbs the charged particles and directs them into the ground like a lighting rod.  I talk more about this in my podcast on this very subject.

Building a Closed Faraday Cage

The difference is with this one, it is sealed and cannot be opened and closed at will, you put in what you want now, seal it and open it when you need it, not whenever you want.

Items you will need

• A Large Roll of unpainted aluminum window screen.
• 2×200′ boxes of Aluminum Foil & Saran Wrap (Hit up Costco/Sams Club)
• Heavy Duty Garbage Bags
• 1 Box Small & Large Ziploc Freezer Bags
• 150′ Industrial Grade Duct Tape
• 50′ Electrical Tape
• Heavy Gauge 3 Prong Grounded Power Cord (Use old Surge Protector, Buy one or use old computer power cord)
• 1 Pack Desiccant Silica Gel
• Cardboard

 Step 1:

Get together all the items you want to protect (remember you cant just get into this whenever you want, so make sure these items are not needed daily/weekly/monthly).  Remove all batteries and store them in ziploc bags (if you leave them in the electronics they will eventually leak and destroy the item.  I would put in rechargeable batteries with the charger for whatever you are using. Try to vaccum seal all the items and then place them ziploc bags if you can, if not just try to get the air out of the ziploc bags.

Sidenote: Eneloop Batteries are some of the best ones out there, they are Low discharge, pre-charged batteries, so they lose their charge very slowly and probably will still have a decent charge when you open the case.  I use a Energizer Family recharger as well, it fits all the rechargeables i use from AAA to D

Step 2:

Once the items are sealed in the bags, wrap them in 3-5 layers of plastic and 3-5 layers of Aluminum foil in alternating layers, plastic wrap should be the inner and outermost layer.

Step 3:

Seal each wrapped item in a zip loc or garbage bag.

Step 4:

If you are using a steel garbage can remove the handles from the side of the can, spread them open and pull them off.  If its an ammo can, sand or grind the paint off of the lips of the container and lid and if the rubber gasket is till present, remove it and scrape away the remnants.

Step 5:

Use strip of aluminum foil to fill any gaps that may be between the seams of metal, even areas where the metal is stamped together or there is a seam there may be small gaps, fill them with aluminum foil will make sure there no gaps in the conductivity of your outer container.

Step 6:

You can line the inside of the can with cardboard or place the items in a cardboard/plastic bin/box

Open and place the desiccant pack(s) place in the container with the items.

Step 7:

Use one long unbroken strip of aluminum foil to create a conductive metal gasket (fold the foil to make it 3-5 layers thick) around the lip of the container, this will ensure a tight fitting conducting lid.

Step 8:

Secure the lid on the metal container and make sure its a tight seal.  If you’re using a garbage can use 2-4 small strips of duct tape to make sure the lid is secured in place, but not too much.

Step 9:

Wrap the whole container with at least 3 layers of foil, you can use a small amount of tap to secure the foil in place, but you want AS MUCH of the metal surface as possible exposed.

Step 10:

This part is more difficult, once you have it wrapped in aluminum foil you must wrap the entire thing in the aluminum screen.  According to the site i went to for this his opinion was to wrap the top and bottom first, vertical first then wrap the body horizontally.  Make sure the screen overlaps so that there arent any gaps, you can use duct tape to hold it in place

Step 11:

Take the 3 prong cord and cut it closest to the surge protector (if its a old computer cord cut it at the base of the female end).  Strip the end and find the green wire (4 inches).  Youll have to strip off the outer layer of insulation and find the green wire.

Step 12:

Cut off the other wires, other than the green and wrap the opening with several layers of electrical tape so that nothing can come out and come into contact with them, leaving ONLY the green wire exposes.

Step 13:

Strip the insulation from the last 3 inches of the green wire, exposing the copper wire.

Step 14:

Find an exposed section of aluminum screen near the bottom of the cage, use a protuding section of the screen.  Poke two small holes in the screen about an inch apart and feed the exposed copper wire in through one hole and back out through the next.  Then twist it around itself to hold it in place.

Step 15:

Once the ground wire is in place, wrap the whole cage in duct tape, A LOT of duct tape.  Us as much as you feel is necessary to hold the aluminum screen tightly in place and prevent it from being damaged.  Also make sure that the cord wont be pulled free from the container so tape the cord to the container.  You need to leave 2-3 feet protruding so that it can be plugged into a wall-outlet.  You should have a container that looks like a big brick of container with a power cord coming out from it.

Step 16:

Plug the cord into a wall outlet (MAKE SURE ITS A 3 PRONG OUTLET). You are taking advantage the grounding in your homes electrical grid.

Notes:

If you are putting this in an outside area or shack you will need to drive a grounding rod into the ground and then strip the whole green wire and wrap it onto the grounding rod.

Also Here is a neat Faraday Cage made from a Metal Cabinet bought on Craigslist.