Originally Posted by Gordon Scott
Originally Posted by justanoldmuso
... apparently also aluminium foil can be used to block radiation
per the net...but not had time to test.
Aluminium/aluminum foil is on of the standard materials for investigating how to reduce EMI/EMF to and from equipment. It's effective provided it has suitable contacts to ground/chassis and does not have gaps/leaks that are a significant part of a radio wavelength long and it does not form a "patch antenna" by having a significant area sticking out into free air.
Back in college I built some microphone preamps. Used a plastic enclosure because they were cheap. They were a little noisy, so for fun I tried shielding one with aluminum HVAC tape - surprisingly it worked VERY well, and I measured something like a 10-15db reduction in noise. I've since done the same with a bass guitar I picked up recently, lined the control cavity with the same HVAC tape, and it helped a lot.

I work here