We've covered what an EMP is and why that EMP Shield thing probably isn't going to save your electronics.
Now for the good stuff: what DOES work?
The Physics (In Plain English)
A Faraday cage is basically an umbrella for electromagnetic radiation.
When electromagnetic energy hits a conductive enclosure, it flows around the outside instead of penetrating to the inside. The key word is ENCLOSURE—complete coverage, no gaps, sealed properly.
Think of It Like This
A screen door with a really fine mesh. Water (in this case, electromagnetic waves) can't get through if the mesh is tight enough. But leave a gap? Water gets in.
Still with us? 😊
What Works: Commercial Options
We're not going to pretend these are cheap—they're not. We've bought ours slowly over time, adding one here and there as budget allows. But they work. And they work well.
Mission Darkness is our go-to brand. Military-grade, lab-tested (MIL-STD 188-125 and IEEE 299-2006 certified), and actually blocks signals from low MHz to 40GHz.
Here's what we actually have:
📱 Phone-Size Bags (~$30-40) ⭐ START HERE
For a spare phone, small power bank, or USB drive with important documents.
View on Amazon →📱 Tablet-Size Bags (~$50-70)
Fits tablets, multiple phones, walkie-talkies, NOAA weather radios.
View on Amazon →💻 Laptop-Size Bags (~$90-150) ⭐ OUR WORKHORSE
This is where we keep the bulk of our electronics. Internal dimensions: 17" x 14". Fits laptops, multiple devices, solar generators, folding solar panels.
View on Amazon →🖥️ T10 Extra-Large Bag (~$200-250)
For computer towers, portable power stations, compact generators. Interior: 15"L x 11"W x 18.5"H.
View on Amazon →📦 Bundle Sets (~$150-200) ⭐ BEST VALUE
If you're starting from scratch, the bundle that includes phone, tablet, and laptop bags is a good deal.
View on Amazon →What's Actually In OUR Bags
Here's where we are NOW (we started small—you can too):
- NOAA weather radios
- Walkie-talkies
- An old cell phone (backup communications)
- USB drives with important documents
- A laptop
- 4 small battery/solar generators (yes, four—added them over time)
- 2 small folding solar panels
- LED lanterns
- Flashlights
That's a lot, right? But we didn't buy it all at once. We started with a NOAA radio and a phone-size bag. Then added walkie-talkies. Then a power bank. You get the idea.
Future goal? Build a proper Faraday enclosure around the gas generator in the garage. That's elite-level prepping, and we're not there yet. But it's on the list.
The DIY Option: Galvanized Trash Can Method
Can you build your own Faraday cage? Yes. Should you? That depends on how much time you have and how handy you are.
Here's the honest truth: We don't have a galvanized trash can Faraday cage.
We looked at the process. We thought about the time. We thought about testing and re-sealing every time we needed to access something. And we thought... who has time for this?
So we bought the Mission Darkness bags instead. They're tested. They work. They're easy to open and close without losing the seal.
But if you want to try the DIY approach, here's what you need:
🗑️ Galvanized Steel Trash Can with Lid (~$40-50)
The Behrens 20-gallon is the most commonly recommended. Made in the USA, galvanized steel, tight-fitting lid.
View on Amazon →📦 Aluminum Foil Tape (~$6-10) — CRITICAL!
NOT regular duct tape. You need conductive aluminum tape to seal the lid seam. This is the part people skip—and then wonder why it doesn't work.
View on Amazon →Cardboard or Closed-Cell Foam — Your electronics should NOT touch the metal sides. Line the inside completely.
The Process:
- Line the inside with cardboard (fluting vertical for structure)
- Address the lid gap with aluminum tape around the rim
- Cover the handle rivets from the inside
- Seal the lid seam with tape after closing
How to Test It
Put your phone inside. Close it. Seal it. Have someone call. If it rings? You have a gap somewhere. A properly sealed Faraday cage should show "No Signal."
What Does NOT Work
Microwaves — The mesh in microwave doors blocks microwave frequencies, but NOT the frequencies from an EMP. Don't rely on this.
Mylar bags alone — Unless they're specifically designed as Faraday bags with proper construction, mylar emergency blankets won't cut it.
Unsealed metal containers — A metal box with gaps is just a metal box. The seal matters.
Cheap "faraday pouches" — Those $5 phone pouches that claim to block signals? Test them. Most don't actually work.
Start Somewhere
You don't need to protect everything at once. Start with:
🎯 The Starter Plan
- A NOAA weather radio in a small Faraday bag
- Add walkie-talkies for family communication
- Add a backup phone and power bank
- Build from there
The goal isn't perfect protection of every electronic you own. The goal is ensuring you have SOME backup capability for power, communication, and information access.
Bottom Line
Commercial bags are more expensive but tested and reliable. DIY trash can is cheaper but requires careful construction and testing. Either way—test your setup. Don't assume it works. Verify it.
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