Aluminum vs Coper shielding tape

I have never used shielding paint, so I won't address it here, but I have used copper tape sold by places that cater to guitar building and repair. I have also used Aluminum HVAC tape, and have commented many times on the forum that it works quite well, at a fraction of the cost of other alternatives.

I just finished a guitar for my daughter, an offset body with strat electronics. In the process I discovered is that not all HVAC tape is created equal. The adhesive on some is not conductive. I have a couple of rolls at home and one is conductive, the other is not. Meanwhile the adhesive in the copper tape I had left over plenty conductive, but there was not enough of it to do the whole cavity. Since I had already shielded the guitar with the not particularly conductive tape, I cut some thin strips of copper tape to connect the highly conductive aluminum surfaces. It worked like a charm.

So...is copper tape better? At least with the copper tape I had on hand, yes, because of the conductive adhesive. But thin strips of it will make even bad HVAC tape just as effective. Good HVAC tape is still a pretty good alternative I think, but I am taking my multi-meter to the big box store the next time I buy it ;-)

While it is also true that it is very difficult to solder to alu tape, I have not actually found it any easier to solder to copper tape. Some folks manage it so YMMV. With both types of tape, I wire a ground wire to a piece of tinned metal that I screw down.

I use copper tape as a preferred method, the stuff I use has the conductive sticky backing 50mm wide I can cut it down to whatever sizes I need, it works well for soldering against for carrying ground wiring. The paint type conductive I have never used but believe its a very good option especially where pickup pockets are visible, black type conductive paint looks better than shiny copper tape sitting in the pockets. There are a few alternatives, I decided the copper was better for the solder side of it rather than aluminium where solder wont work.

Copper tape and conductive paint are tried and true.

I haven't used paint, but I can certainly see applications for it, particularly in tight spaces since it is so thin and form fitting. Also no danger of an accidental ridge causing a short.

I have not been bothered by the shine of copper or aluminum under pickups. But if I were, paint would be an elegant solution. Still, since I have already put HVAC tape in the guitar, I'd probably just put some black tape under the pickup to cut down on the glare ;-)

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Shielding paint is good, but it is very messy, so definite apply it after all your other finish work is done. The carbon dies cone off on your fingers very easily, and it’s easy to leave dirty prints all over the finish that don’t come off all that easily.

On the last body I worked in (a very early 70s Greco Strat), I tried using it just like copper tape so it ran on to the top of the body. I was still working on the body, and was forever getting marks on the off-white body. I eventually took the paint off the top of the body, masking a few areas off, then sprayed clear over the shielding paint. Then ran copper tape from the bare areas up to the top to
make contact with the pickguard tape. I ended up fully shielding the cavity with tape as well, so it’s doubly shielded.

So I’d always add the shielding paint as the last thing before assembly, and it is best with running ground wires to it so you don’t need to run it over top edges for connecting to a grounded surface. Once all grounded, a single coat of clear is a good idea to keep things clean.

The only difference is price between the 3. From my experience the paint is a little on the high price side, the copper tape is lower and aluminium is by far the cheapest.

Paint is by far the easiest to apply and can be used easily to shield in holes that run between cutouts, if so inclined.

Nearly all copper tape has conductive glue but I have only come across 1 that didn't have good electrical properties. You can overcome this by using a physical join like a staple, a piece of wire with a screw or just a screw with a washer or foil that is held down with tape.

Aluminium is by far the easiest and cheapest to apply as you can just use foil that you cook with and seeing as you can apply it in a single piece there is no need to worry about what glue to use.

As for glue you can use any contact adhesive if you are putting in it in a single piece. If you are using multiple pieces, you can buy conductive glue but it isn't really as cheap as contact adhesive. You can also use the same solutions as copper tape to overcome continuity issues.

You can solder aluminium but the temp is a lot higher than copper and the temp will effect your glue and probably make a bubble between the wood and the foil.

I have done numerous guitars with and without shielding and while the copper tape was good the aluminium foil was by far the easiest and cheapest.
BUT you have to use a multi-meter to check all the pieces are ground and you have a good ground back to the jack otherwise you can use whatever you want and it wont work.

One benefit of copper over aluminium is that copper oxide is conductive (though not as conductive as copper itself) whilst aluminium oxide isn’t.

Aluminium oxide forms a fairly impervious surface layer but doesn’t go deeper, so the rest of the foil remains conductive. But over time you’re more likely to have issues than copper with joints and ensuring ground connectivity unless you can keep the foil connections sealed against the air.

Whilst aluminium has been used for decades to shield wire, so there's no real challenge to it's ability to shield, I am still a bit confused about the price issue. a 10m roll of 50mm copper goes for under $15 with the adhesive specified as conductive. Sure you can spend more on name branded, but the cheap stuff seems just fine. considering how much everything else costs, is the price difference between copper tape and aluminium really such an issue?

A roll of HVAC aluminium tape costs about £1/AUD$2 here in the UK and a 30m+ roll of copper tape about £10 (gone up recently), so copper is relatively more expensive, but both are very affordable options and a very small percentage of the cost of building a guitar. I can get a 125ml can of good shielding paint (Rustins) for less than £10 as well, though other makes seem to be a lot more expensive, and the small plastic bottles of it found on luthier’s sites downright exorbitant! I’ve used my shielding paint on at least 6 guitars plus some touching up on others, and still have about half the tin left.

1+ on testing continuity.

Copper tape is not prohibitively expensive, for sure. It adds up when you do multiple guitars though. Most times I see copper tape on guitar building/repair sites in amounts just enough for one guitar.

By contrast a $5 role of HVAC tape (that I have in abundance living in Florida) is virtually a lifetime supply and I had a lot of it. I have not had oxidation issues with it. It tends to remain nice and shiny, and stuff that I have had on my garage door for years has remained conductive.

HVAC tape is also available everywhere here. If I run out, the big box store has plenty. However, I have never run out. I have two roles because I misplaced one of the roles.

Cheap and available means that I don't worry about messing it up. If something is not right, I can rip it out and do it again without worrying about reordering.

I have actually just ordered a small amount of copper tape, since it is great for curing any continuity issues. That said, I do like cheap and available, so I will probably keep using the HVAC tape too. It is not better in any intrinsic way than copper or paint to my knowledge, but it works.

Thanks for the rundown on the shielding paint. Was not aware of the issues with using it! That will be really useful. Thanks also for the ideas about conductivity enhancers. A staple is such a simple solution! Also, I was not aware that there was conductive adhesive.

This is the sort of stuff you should be looking at in the US for copper tape with conductive adhesive.

https://www.amazon.com/s?k=copper+ta...f=nb_sb_noss_1

A mixture of thick and thinner (say 4" and 1") reels should sort you out for most jobs if you want to use copper.

I'd expect most aluminium HVAC tape to have conductive adhesive. Certainly in the UK there's a requirement for the ductwork to be boded to earth/ground, and if the tape is being used to join two pieces of duct together (rather than patch up a hole) then it saves having to run an earth strap between the two pieces.

It may well have a coating on it to stop it corroding. It's not something I've used myself in a work situation as I'm looking after the HVAC controls rather than the physical ductwork,, but I've seen it used.

Thanks. I don't know what the standard is in the US. The HVAC tape here (or on Amazon) does not generally say whether the adhesive is conductive. I have two rolls from different mfgs...and one is one is not. We *should* have such a standard, but I guess that means we may not.

Meanwhile those are much better prices than the last time I looked. It's about twice the cost as alu tape, but double the cost is still pretty cheap...and since it says it has conductive adhesive you know what you're getting.

I guess if you don't mind the patchwork look, then your idea of using the copper tape to conductively connect the aluminium is a good compromise, with the added benefit that it gives you points you can solder to if needed. Generally I used ebay if I want cheap, and Amazon if I want fast. Here in Oz Amazon is generally more expensive.

Ss long as you have conductive adhesive tape (which I would say is a necessity as it’s easily available), you can always connect a ground wire to it (given enough space) by taping down an exposed length of wire, forming a tape sandwich. This works best if joining two shielded areas together so the wire won’t be moved, rather than a wire that’s going to be soldered to the back of a scratchplate-mounted pot at one end and so liable to get pulled as it’s moved.

I have more of the copper tape on order. Thanks for the link. On my last build, (an offset guitar with Strat electronics). I had just enough of the copper tape to do .25" strips to make continuity with the 2" strips of aluminum tape. I sort of liked the way it looked. Silver with copper spiderweb. Of course no one but me is every likely to see it. To connect the ground to the wiring harness I used an eyelet connector like this:

Attachment 44728

I pried open the "tube" and flattened out the sides so that they were like wings. I soldered the bridge ground wire to one side, and a wire going to the volume pot to the other. That way if I need to take out the pickguard, I just have one wire to de-solder. With all the jostling a guitar will get, I am not sure I'd trust just taping down a ground wire.

I tested continuity before closing it up. Once closed up, I tested it with one lead on the jack ring, and the other on the strings, the pots, and the pickguard screws that connect the body shielding with the pickguard shielding.

I just checked and eBay here has the same copper shielding tape for a little more than Amazon. Here Amazon is generally faster (though that is no longer always the case), and also often the same or cheaper than eBay for things they sell a lot of. Guitar parts I have generally found cheaper on eBay...particularly if they are better quality.