Who hasn't experienced this: You're playing a beautiful number, maybe the recording recorder is also running - and something is humming. As soon as the guitarist or the bassist turns a little, the humming becomes less.

The cause for this is almost always the so-called mains hum with approx. 50Hz. Here the pickup (actually only magnetic single coil types) reacts as an antenna and receives e.g. the EMC pollution of your guitar transformer or e.g. the neon tube on the ceiling.

Minimizing the "radiation dirt" in the air is often more difficult than professional shielding in the guitar itself.

Here I show how I shielded the millwork on a Telecaster conversion to Duisenberg P90 pickups.

There are several shielding possibilities. Actually, it is always a matter of building a metallic conductive sheath, which is to be connected to the ground line.

I name two variants:

Sticking with metallic conductive foil

• Copper foil

spray or better brush with metallic conductive paint

• Copper conductive paint
• Graphite color
• Silver conductive lacquer
• EMC Shielding (eg copper-based)

Some may think it is also possible and cheaper to use aluminum foil in the cavity - please do not do it!

If you use self-adhesive aluminum foil, e.g. as used in heating systems, the strips cannot make contact with each other. A closed shielding cage can hardly be achieved in this way. 
If you are talking about the complete aluminum shields attached to the underside of S-style pickguards, this is something else - because they are not made up of individual parts but are conductive as a unit.
Here you have to make sure that both the shielding of the cut-out and the cover make contact with each other.

If you are looking for shieldung products, please see in our shielding category or below the shilding paint.

Link to the category for shielding: LINK

Link directly to the shielding paint: LINK
 

Procedure for correct shielding:

• Define shielding concept: which cavities to shield?

• Where to attach connection points (1x per shielding area),

• Where to connect the connection points?

• Also shield pickguard, PU compartment cover (connection)?

• Roughen the painted surface slightly with sandpaper.

• Glue a piece of copper foil measuring approx. 1.5x1.5 cm in a suitable place.

• Punch a small hole in the middle with a pre-cutter and then screw the soldering eyelet into it.

• Paint the copper foil and screw with shielding paint. This increases contact and conductivity.

• Apply 3 coats with a soft brush.

• Allow approx. 2 hours drying time between applications.

• Allow to dry overnight.

• Connect the connection points electrically to the ground of the instrument by soldering (e.g. back of the potentiometer housing).

We have been using our water-based graphite shielding paint for years.
We also sell these in 30ml and 50ml packaging. All our shielding paints come complete in a set - including soldering lugs, screws, cables, etc., which you would otherwise have to buy separately.
Of course, illustrated instructions are also included.

Please see here some pictures of how to do it:

Here is an example of a clean copper lamination including electrical connection.

You can also clearly see the head foils glued to the top side. The aim here is to establish contact with the pickguard shielding. When the pickguard is screwed on, the electrically conductive surfaces touch and so the shielding is also closed on the top side.

Cut the strips of copper foil to size with scissors and glue them neatly and tidily - even in the corners. Leave an overlap of 1-2 mm at the joints and use the soldering tool to place a soldering point at any point where the solder creates an electrically conductive bridge between the two strips, so that each copper part is then connected to each other. As with the other shielding options, this shield must always be connected to the earthing of the electrical circuit (e.g. to the back of the potentiometer, where the overall earthing is also connected.

We have also used water-based copper conductive paint - environmentally friendly, fast drying and super-tight. Here the manufacturer promises a shielding effect of over 60 dB (99.9999%). 
The copper base is very expensive and in practice does not shield better than graphite paint.

But to round things off, such a shielding with copper conductive paint is shown here.

It is very important that the conductive particles are evenly distributed in the paint. To do this, stir well with the plastic whisk (5-10 minutes !).

And stir!

Important: the shielding only works properly when the entire conductive jacket is connected to ground! This is done by sticking a piece of one-sided adhesive copper tape under the shielding paint as a soldering base. If one brushes the shielding paint over the tape, the connection is created between the tape and the paint.

Painting the surfaces according to the manufacturer's instructions (here 2-3x)

A piece of cable is soldered onto the copper strip and then connected to a potige housing, e.g. in the electrical compartment. With the ohmmeter you can still measure the shield resistance. In the distance of approx. 6 cm to the shielding surface held the measuring instrument must indicate less than 1.5Ohm. Perfect!