Shielding with aluminium on pickguard and copper in the body cavities

DrPepper

As in the title I was wondering if there are known risks in doing the above. I ask this because I've acquired what looks like an aluminium strat pickguard and wondering what are my best shielding options. 

I have a full roll of conductive copper tape and was going to use that to shield the cavities however have heard rumblings (literally one forum thread on google) that mixing the shielding metals could cause issues with electrolysis and oxidation and other GCSE chemistry terms I've long forgotten. So my options are as follows:

1. Ground the actual pickguard itself seeing as it's aluminium, discard the copper tape and get some aluminium (conductive?) tape to shield the cavities
2. Use the copper tape in the cavities and apply the same tape onto the aluminium pickguard as well
3. Don't use the aluminium pickguard in the first place and get an acrylic pickguard with a chrome/mirror appearance, shield with aluminum on back and aluminium in the cavities
4. As above but shield with copper tape

I hope this question hasn't been asked too many times but seems like a "mix" of shielding materials isn't discussed much and wanted some advice on this. 

Thanks fretboarders!

ICBM

It will be fine as long as there's no moisture to allow electrolytic action. If there's enough moisture to do so you will probably have other problems with the guitar...

I've never found aluminium tape very easy to work with for shielding, much prefer copper.

If you're concerned about it, the simplest solution is to use copper tape but stop it just short of the top of the cavity, or cover the edges with insulating tape, so there's no contact between the two, and ground the copper shielding separately with a soldered wire - which I prefer to do anyway, to guarantee a really good connection. (I also always spot-solder across each tape joint - you only need one between any two piece of tape.)

normula1

+1 on the spot soldering as the conductivity of the adhesive breaks down over time.

DrPepper

Sounds like some solid advice thank you @ICBM and @normula1 .

So I guess I'll stick (lol) to the copper tape whilst soldering across tape joints. 


Could I apply copper tape to the pickguard to join with the cavities or I could use some wire to ground the actual pickguard?

Corvus

Run the tape over the body top a little way, like a 'ledge', is the usual way. It'll make contact with the p/g when it's fitted. Like this sort of thing, people manage tidier jobs than me but -
http://alleykat.co.uk/images/stuff/strat/14_painted.jpg

Or shielding paint. I got some waterbased a while back, it's good, conducts well and lays down well, dries fast too. Instead of the overlap all round paint a "lobe" up around handy mounting screw so it bridges up to the p/g when screwed on. I scuffed up the cavities a bit to help it stick better than it might to smooth gloss.

ICBM

DrPepper said:

Could I apply copper tape to the pickguard to join with the cavities or I could use some wire to ground the actual pickguard?

You don't need to ground the pickguard because the pots are mounted on it so it's automatically grounded.

If you do the tape as Billkat showed above you don't *need* to ground the foil either, but then you're relying on the contact around the edge of the tape - which if a bit of corrosion does get in, or if the guard is not perfectly tight to the body in the middle, can be poor - so I still prefer to solder a wire to the foil somewhere and connect that to the back of the volume pot.

If you do that you can then trim the foil to just below the rim of the cavities and eliminate the possibility of electrolytic corrosion as well.

I've never found conductive paint very effective, in fact several of the shielding jobs I've done have been with foil over existing paint because the guitar was still noisy - and which fixed it.

Corvus

That's a point, I do have a wire going from a tag screwed into the cavity wall going to a pot as well.
I've had dubious paint before, but this doesn't hesitate in meter tests and feels 'thicker', more solids, than prev solvent based ones. Bought it as a trial since I'd made the cavity a slightly PITA shape for tape but it seemed a cut above prev tins so went ahead with it. The guitar's nice and quiet. Just hope it does stay adhered well longer term.