How to build a faraday cage

July 27, 2012 11:52 AM

I'm interested in making a strong faraday cage device to protect my stuff, one that is walk-in.

Any plans, leads, or ideas on how to construct such a device? I've seen a few plans online on how to build one with mesh or with a metal wire type of framework, but I'm hoping that I can make something a little more concrete, if that's possible, or alternatively, where I could find that kind of room that I could rent out.

posted by Query to technology (11 answers total)

What stuff are you protecting and what's going on in your environment that you need a Faraday cage to protect it?
posted by griphus at 11:53 AM on July 27, 2012 [5 favorites]

Protecting what stuff from what, specifically? That makes a big difference in the design specs.
posted by Sidhedevil at 11:54 AM on July 27, 2012

The easiest way I can think to do this is to simply line the room the foil. Then maybe drywall over the foil to protect it...?
posted by Specklet at 12:05 PM on July 27, 2012

How large does it need to be? You could make a mesh wall-covering for an existing room, whether it be a closet or a bedroom.
posted by Joh at 12:05 PM on July 27, 2012

Lightning strikes, Tesla coils, EMPs - I'm guessing you're thinking about the later.

I'd suggest complete surface coverage with kitchen foil, mounted with spraycan adhesive and foil tape - you can adapt an existing space with minimal visible change and little fuss. Save the mesh work for windows and air ducts.

Kitchen foil is Al, which forms a (non-conductive sapphire) surface coating, so you'll want to check your connections, but in my experience, Al roofing tape seems to make a decent enough electrical connection even though not (AFAIK) designed to.
posted by -harlequin- at 12:06 PM on July 27, 2012

This doesn't exactly answer your question, but the SF Bay Area Maker Faire always has at least one for playing around with the Tesla coil. Do you have a handy Makers Faire so that you can go check them out? There are a ton of pics and videos of it online, too.
posted by small_ruminant at 12:45 PM on July 27, 2012

Yeah, let's assume an EMP for argument's sake, or maybe radio waves. Definitely not a lightning bolt or something like a tesla coil.
posted by Query at 12:49 PM on July 27, 2012

Right, but a faraday cage is a faraday cage, isn't it? (Actual question). The Maker Faire ones are durable and would probably work for physical security, too.
posted by small_ruminant at 12:56 PM on July 27, 2012

You can do this with wallpaper
posted by yoyo_nyc at 1:09 PM on July 27, 2012 [2 favorites]

I'm hoping that I can make something a little more concrete

For EMP or radio isolation you could use cast concrete with a crystalline graphite additive. The graphite is conductive, so the isolating effect was presumed to be like a Faraday cage, but it may also be due to the reflection of magnetic radiation.

Graphite-doped cast concrete with copper wire mesh inside and out should do the trick.

Or if you are not the NSA, any conductive wire mesh or tin foil should work.

(Memail me if you are looking to acquire crystalline graphite in quantity.)
posted by StickyCarpet at 1:53 PM on July 27, 2012 [3 favorites]

At my previous job, we had one of these shielded chambers for conducting electromagnetic tests. They're not cheap, but they come in a variety of sizes.
posted by aecorwin at 10:00 PM on July 27, 2012 [1 favorite]