I was reading a few pages about materials used for constructing a faraday cage and many mentioned that they used fine brass mesh/screen to block the waves. This seems a little excessive when aluminum is much less expensive. I was wondering if window screen could be used and if the holes are too large then a double layer might be better.

If the goal is to block an EMP or cellular, GPS, wifi, and radio waves what is the size opening that is acceptable in the mesh and is there any commonly available metal that is unacceptable?

Finally does the mesh need to be grounded or can it be used without grounding?

 

Aluminum is a good conductor, and cheap, but aluminum mesh is pretty lame, because of high impedance of mechanical connections (aluminum oxidizes instantly, and aluminum oxides are non conductive), as well as no magnetic characteristics.

A steel box is one of the best Faraday cages.

 

This is a great Faraday cage if properly electrically sealed on the handles and lid.