by AuntAnnie 08 Aug 2019

I recently posted a question in the wrong section here regarding the radio frequency blocking properties of Insul-Brite. I have since done some internet research as well as hands-on experiments and have come to the conclusion that Insul-Brite--as well as some potato chip bags--do block at least enough radio waves to make these products suitable for use in handbags or clutches to protect your credit cards or cell phone from unwanted scanning.

This simple test involves placing a cell phone inside the material and calling the number of the device. If the device receives the call, the material is not blocking radio waves; if the device does not receive the call, the material is blocking radio waves and should protect your device and credit card from thieves.

Have fun doing your own experimentation!

The statements contained here are not a guarantee or warranty but are based on my own experiences. Please take common-sense precautions to protect yourself and your belongings.


by cfidl 09 Aug 2019

Wonderful work! I have used the balloon mylar in the past for this, and have collected a candy bag. I have asked at the bank and at the grocery store if they had the device to see if it worked. I got weird looks. Lol! I like your method so much better and will do some testing on my own. My son put the external speaker on the front porch and took the phone across the street where it still received enough of the signal to hear the song playing well.That is at least 25 yards. The waves do go a great distance and I am not sure I want the 5G and the 10G to come to town. But nobody listens to me. I just heard on the news that they are also capturing the signal from your car keys and breaking in to get whatever valuables are there.

1 comment
Renga by Renga 09 Aug 2019

I heared about stealing the car by scanning the key signal ...

by marianb 09 Aug 2019

thanks well worth trying

by momac 09 Aug 2019

Thanks for this info, their is enough crime going around, that it is good to have a something like this to fall back on.

by dollygk 09 Aug 2019

Who knew that a bunch of women doing machine embroidery would involve scientific experimenting for purses and privacy!!! he he

by Renga 08 Aug 2019

Good idea! I will take 2 layers of aluminium foil between inside and outside fabric to protect my "keyless go" car key from being scanned. Now thinking of a new handbag with aluminium foil interface ...

by sewdoctor 08 Aug 2019


by graceandham 08 Aug 2019

Thanks. Brilliant testing.