Shielding

[Greefy67]

I’ve got a Squire Affinity P Bass.. 

its been mentioned to me that it might need shielding. It’s pretty quiet until I go near my beardies Viv. But a definite hum that’s louder the closer I am to it. The hum doesn’t go away when I touch the bridge or strings, but it does get quieter..

suitable job for a home bodger?

thanks

 

[Dan Dare]

Yep. Straightforward job. You can get self adhesive copper screening tape off Amazon or eBay quite cheaply. RS Components do a decent sized roll for not too much money, too, if you want a bit more. You just need to unscrew and lift the scratchplate and stick it all over the inside of the body cavity (one layer is fine - no need to use yards of the stuff). Make sure it doesn't short against the jack terminals or any of the wiring. Remove the pots from the scratchplate and put a layer over the inside of the plate where it covers the body cavity. Then poke a hole for the pots and replace them. That will earth the pot bodies to the screening tape. It sounds as if your bridge is grounded already if the hum quietens when you touch the strings

[Chienmortbb]

Two points. Aluminium tape is better for screening but it cannot be soldered. Secondly even if the adhesive on the tape is said to be conductive, it is wise to solder the joins.

 

[ped]

I think conductive paint is best for the body then use foil on the back of the scratch plate 

[Lozz196]

Ive just used the copper tape on the scratch plates on my basses and it’s worked fine.

[gary mac]

I've shielded many instruments, using Copper tape. I haven't resorted to spot soldering the joins as a check with a multimeter has always shown continuity. Job done.

[Geek99]

12 hours ago, Chienmortbb said:

Two points. Aluminium tape is better for screening but it cannot be soldered. Secondly even if the adhesive on the tape is said to be conductive, it is wise to solder the joins.

 

What not buy a small roll of copper with conductive adhesive and join the aluminium with small strips of it ? Much less trouble 

[Chienmortbb]

6 hours ago, Geek99 said:

What not buy a small roll of copper with conductive adhesive and join the aluminium with small strips of it ? Much less trouble 

Probably the best option. 

[Geek99]

On 19/06/2019 at 20:12, Chienmortbb said:

Two points. Aluminium tape is better for screening but it cannot be soldered. Secondly even if the adhesive on the tape is said to be conductive, it is wise to solder the joins.

 

I used the conductive glue copper tape  and got 0.0001 ohms resistance from the furthest point to the jack ring. It’s good enough 

[Stub Mandrel]

Copper should be superior to aluminium, it's more conductive although I doubt you could detect the difference.

You can solder aluminium by abrading the oxide layer off the surface with wet and dry, putting  something like 3 in 1 oil on it, and then using a scratching technique to get the solder to wet it under the oil. I've used this technique to attach wires to aluminium panels.

[Chienmortbb]

On 20/06/2019 at 22:30, Stub Mandrel said:

Copper should be superior to aluminium, it's more conductive although I doubt you could detect the difference.

You can solder aluminium by abrading the oxide layer off the surface with wet and dry, putting  something like 3 in 1 oil on it, and then using a scratching technique to get the solder to wet it under the oil. I've used this technique to attach wires to aluminium panels.

It is not about the conductivity, it is about the shielding effect.

[Stub Mandrel]

1 hour ago, Chienmortbb said:

It is not about the conductivity, it is about the shielding effect.

True, it's acting as a Faraday shield. It's effectiveness is dependent on the 'skin depth'. Copper's skin depth is considerably less than that of aluminium at any given frequency BUT for both metals it is thicker than the sort of foil used at 50Hz, so they will perform equally well.

The difference does matter if you are shielding against radio frequencies.

[Christine]

I was told that copper was better for shielding as it has ferric properties (something to do with electrons I believe) but I really don't understand any of it.

[Greefy67]

So, I finally decided to do something about the infernal interference buzz through the Squier. It did it when it was near any kind of transformer. Fluorescent and downlighting being the worst. Copper tape from Amazon, it stated it had conductive adhesive. And while I was in there. Clean the pots and fit a new set of pickups to replace the corroded ones that offended my eyes. The result? No crackles from the pots. No interference from the lights. And it actually still works. So while the strings were off I even treated the fretboard to some lemon oil (note to self.....ewwww. That cloth looked nasty by the end). Behold the Squier Greefy 67 Precision bodge. One thing I did learn is a new respect for glasses wearers. I only need readers. But it was close up work. It’s hot this evening. Glasses really suck when you get a sweat on. That is all.

[gary mac]

Nice job. 

[Andyjr1515]

Yes - great job & good result!

[rmorris]

On 03/07/2019 at 20:42, Christine said:

I was told that copper was better for shielding as it has ferric properties (something to do with electrons I believe) but I really don't understand any of it.

No. Copper is non ferrous ie not ferric. Metals with Ferric properties contain Iron (Fe in periodic table) so  basically irons and steels. Aluminium is also non ferrous.