When the guitar signal is interfered by unwanted noise, like hum from a guitar amp transformer or a computer monitor, shielding the potmeter and switch cavity and sometimes even the pickup spaces can help to manage a clean signal.
For shielding I use a special 3M copperfoil tape, designed for shielding. Sometimes you see aluminum shielding tape used on pickguards, however, aluminum tape is mostly used for heath protection and not for shielding.
Typical all parts have to be removed to apply the shielding, so it is also a good moment for general soldering work or modifications.
Noise generated by the pickups itself (like P90 soapbars) can not me removed by shielding.
This electric guitar needed to be as noiseless as possible with the current pickups. The electronic was rewired completely, and the cavity was covered with cupper foil.
The copperfoil is put in the cavity. This way all components will become in a grounded metal box.
After rewireing, the guitar is indeed a bit more silent. It is also a bit more clean and clear if a future repair should be taken place.
Before all caveties can be fitted with a special shielding foil, all parts need to be taken off the instrument. The wiring is checked at the same time.
The foil can now be applied to the cavities. All shielding parts are connected with a central grounding wire.
All parts (pickups, bridge, electronics, output) are put back in place. This modification makes the guitar more quiet.