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GoDark® Faraday Bag for Tablets
€73,95
Why Do Faraday Bags Stop Working
Most people assume a Faraday bag fails because signals somehow “gets through.” In reality, failure usually comes down to two things: quality of the shielding fabric and everyday wear and tear.
First, cheap knockoffs are often made with the lowest-cost materials, which means they don’t hold up well. Many reviews on forums and marketplaces mention Faraday bags that stop working quickly or never work at all. In this case, the lower price comes with trade-offs in reliability.
Second, daily use takes a toll on Faraday bags. Abrasion, corrosion, and gaps in the seams can damage the shielding fabric allowing signals to pass through. Once that happens, your phone, fob, or device can be tracked again.
GoDark Bags solve this by adding a protective liner around our lab-tested shielding fabric, preventing damage and preserving conductivity. This means your privacy stays protected for years, not just months.
To see how this happens, it helps to first understand how Faraday shielding works.
How Faraday Shielding Works
A Faraday bag works because its shielding material forms a continuous conductive barrier that reroutes field fields energy around whatever’s inside. That’s the basic “Faraday cage” idea first studied in physics and described in engineering analyses of mesh and wire cages.¹
How well that barrier blocks signals depends on two factors:
- The material’s electrical conductivity– how well it can carry and redirect electricity (and in this case, signal energy). The better the conductivity, the stronger the signal blocking.
- The barrier’s geometry – how tight or dense the weave or mesh is. A fine, tightly woven conductive fabric blocks more frequencies, while bigger gaps let some signals pass through.
That relationship between conductivity, mesh/structure, and shielding effectiveness is shown in lab studies and mathematical models.²
Conductive textiles also can reach strong shielding at many radio frequencies, but their performance depends on coating quality, layer count, and how the fabric was made. Tests also show shielding varies with frequency (so a fabric that blocks some bands well might be weaker at others).³
So, if the shielding fabric is what does the blocking, then what happens to that fabric after months of folding, stuffing, or rough use?
How and Why Fabric Degradation Happens
The shielding fabric is the bag’s most important feature, but it’s also its most fragile part. It’s not indestructible, and here's why:
1. Wear and Tear from Everyday Use
Studies show that repeated abrasion (e.g., rubbing or folding) causes cracks or wear in the conductive patterns.
Over time, this raises electrical resistance and cuts into the bag’s blocking power.⁴
2. Chemical Damage and Washing
Detergents, sweat, water, and heat can corrode or dissolve the conductive metals, especially silver or copper coatings.
In lab tests, silver coatings on fabric peeled off, and stainless steel threads lost shielding strength after repeated wet cleaning, much more than after dry cleaning.⁵
3. Seams, Closures and Geometry Matter as Much as the Fabric
Even the best shielding fabric won’t protect your devices if seams, zippers, or openings create gaps. That’s why we use a double roll-top closure to keep signals out without compromising the bag’s integrity.
Reinforced seams, secure closures, and careful design all help the Faraday bag last longer and keep your devices safe.
To guard the shielding layer from daily wear and accidental damage, we also include a protective liner.
GoDark’s Protective Liner
GoDark’s protective liner is a soft layer of material sewn inside the bag. Its job is to create a barrier between your device and the shielding fabric. Without this barrier, your phone or other items sit directly against the shielding layer, rubbing against it every time you put them in or take them out, or from constant rubbing while in the bag.
Over time, that constant friction can wear down the shielding. Sharp edges, dirt, or rough phone cases and metal or rough-edged key fobs can act like sandpaper on the shielding material.
When that fabric begins to fray, the bag won’t work as well as it used to, weakening its signal-blocking power.
That’s why GoDark Bags use a soft polyester felt protective liner. When you put your device inside, the felt separates it from the shielding fabric. This means your phone and anything sharp or abrasive on it never rubs directly against the protective material, helping your Faraday bag last much longer.
When Is It Time to Replace Your Faraday Bag?
Knowing the signs of wear can save you from thinking your devices are safe when they’re not.
1. It no longer blocks signals.
The easiest way to check is to test it. Put your phone inside, seal the bag, and try calling it or sending a message.
If the call or message goes through, the bag’s shielding has likely failed. You can also test with a key fob or Bluetooth device. If the connection still works, it’s time for a new bag.
2. Visible damage on the inside or outside.
For bags without a protective liner, you can check for scratches, tears, or frayed edges, especially along the inside.
These signs often mean the conductive fabric may already be broken and letting signals through.
3. Persistent odors, stains, or corrosion.
Sweat, moisture, and spills can cause corrosion on the shielding layer. If the bag smells bad, has stains you can’t remove, or shows signs of metal corrosion, it could already be compromised.
This is why it’s important your bag has a watertight outer shell to protect the shielding fabric from exposure in the first place.
GoDark Bags are designed with a tough 600D polyester outer shell coated with PU (polyurethane) coating on the outside and a layer of TPU (thermoplastic polyurethane) on the inside. The seams are RF-welded, making the bag highly resistant to water and punctures, and strong enough for heavy, frequent use.
4. After heavy or long-term use.
If you’ve been using the same bag every day for years, it’s smart to test it regularly and replace it once you notice even minor performance issues.
A Faraday bag is only useful if it’s working at full strength. If you see signs of damage or it fails a simple test, it’s safer to replace it than risk your devices being exposed.
At GoDark, we care about more than just blocking unwanted signals; we care about keeping your Faraday bag working at its best for as long as possible. That’s why we add an inner liner to protect the shielding fabric itself. Think of it as protecting what protects you.
Because yes, all Faraday bags will eventually wear out, but we design ours to stand out, last longer, and give you more peace of mind.
Frequently Asked Questions
What Makes a Faraday Bag Work?
A Faraday bag works by using a special shielding fabric made with conductive metals. This fabric blocks signals like Wi-Fi, GPS, and Bluetooth from reaching your device. When you put your phone inside and seal the bag, you create a barrier that keeps interfering signals out and your data private.
Why Do Faraday Bags Fail?
Faraday bags fail when the shielding fabric gets worn, scratched, or damaged. GoDark provides a protective liner that protects the shielding fabric from rubbing against your device, which helps your bag last longer and keep blocking unauthorized signals.
How Do I Know if My Faraday Bag Is Working?
You can test your Faraday bag by putting your phone inside and trying to call or send a message. If no signal gets through, it’s working. For extra peace of mind, test it regularly, as wear and tear can reduce its blocking power over time.
Sources:
¹ Chapman, S. J., Hewett, D. P., & Trefethen, L. N. (2015). Mathematics of the Faraday Cage. SIAM Review, 57(3), 398–417. Read here
² Dariusz Wójcik, Surma, M., Mirosław Magnuski, Blachowicz, T.,KhorolsurenTuvshinbayar, Dotter, M., Yusuf Topuz, & Ehrmann, A. (2023). Experimental Verification of the Shielding Properties of Selected Textile Materials in the X Frequency Band. Applied Sciences, 13(17), 9777–9777. Read here
³Manogaran, R., & Murugesan, M. (2025). A review on recent advancements in textile fabrics for electromagnetic interference (EMI) shielding materials. Materials Today Communications, 44, 111879. Read here
⁴Biermaier, C., Bechtold, T., & Pham, T. (2021). Towards the Functional Ageing of Electrically Conductive and Sensing Textiles: A Review. Sensors, 21(17), 5944. Read here
⁵ Pušić, T.,Šaravanja, B.,Malarić, K.,Luburić, M., & Kaurin, T. (2022). Electromagnetic Shielding Effectiveness of Woven Fabric with Integrated Conductive Threads after Washing with Liquid and Powder Detergents. Polymers, 14(12), 2445. Read here
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