Strat Shielding

[Willabe]

I decided to shield my Strat cavity, should have done it years ago.   

I read some complaints about Stewmac shielding paint being high in resistance when checking with a meter and some copper tape that was supposed to have conductive adhesive on the back but didn't. Other guys had very good results with the copper taper or Stewmac conductive paint.      

So, I chose MG Chemicals 841AR nickel conductive paint instead. Pricey stuff but seems to have worked very well?

I used a plumbers acid brush, cheap, short handle, disposable, to apply it. It went on pretty thick with just 1 coat, 2 - 0.4fl. oz/15ml bottles. After a week of drying I get 2.8ohms from the furthest points of the neck and bridge PUP's, and 4.7ohms from the furthest part of the neck PUP to the furthest part of the 1/4" jack route. I used a Q tip to apply the paint in the 1/4" to main cavity hole. It worked pretty good.

Does that sound low enough in resistance? I read where other guys that used copper tape or Stewmacs paint were getting anywhere from 200ohms to 50ohms. That seems high to me. Some guys didn't even have continuity with the copper tape. 

After I put it back together, I'll decide whether I'll change out the cloth PUP hook up wire for shielded wire. I want to hear how much difference just the conductive paint made first. 

Willabe

https://www.amazon.com/MG-Chemicals-Nickel-Print-Conductive/dp/B01M28SRH0/ref=pd_lpo_1?pd_rd_i=B01M28SRH0&psc=1

[pdf64]

I wouldn’t worry about a few ohms here or there.
Off the top of my head, I guess that anything under 1k would be fine.
Bear in mind that just touching the strings does a pretty good job at shielding the back of the guitar, and string to skin contact impedance is likely to be higher than that.
I did my strat about 15 years ago, using the stewmac copper tape. Its conductive adhesive backing worked fine, but I made a soldered connection between each piece too, just in case.
Don’t expect a night and day difference.
I got some noiseless pickups soon after 
I’ve not bothered screening another strat I got later, even though I’ve still got heaps of tape left.

[Willabe]

I wouldn’t worry about a few ohms here or there.
Off the top of my head, I guess that anything under 1k would be fine.

Ok, good. 

Don’t expect a night and day difference.

I thought I'd try it and see what it does, can only be better. I turn to a quieter spot/position so then it's not too bad as it is now.

I'll probable try the shielded hook up wire afterwards, see what that does. Again, can't hurt.

Thanks pdf64.   

Willabe
 

[acheld]

A couple of ohms won't be an issue.

I've never had trouble with the Stewmac tape, but any time I've had a problem with their products, I just call or email and they send me a new part.

I had so much trouble with one guitar that after I installed the tape, I had 1 ohm resistance front to back -- and went back an soldered a small tag (of solder) from one piece of tape to the next to ensure total continuity.  Easy to do, and ended up with less than an ohm.  In that repair, I also replaced the wire from the cavity to the trem pocket (yup, a Strat).   

Sometimes a haphazard approach works just fine; sometimes you have to pay attention to detail.

[tubeswell]

I shielded an old '89 American Series strat I had using Aluminium foil tape. It did reduce the hum quite noticeably, and I kept it for about 15 years after that and used it a lot in venues where there were PAR light cans rigged up etc, and it did help keep hum down quite a bit (and I sold that geetar a couple of years ago still with the shielding intact - but I sold it for other reasons - needed a re-fret). But to do it properly/effectively you have to shield the whole cavity (sides, back and behind the scratch-plate) and ensure the ground returns for the guitar are all wired to avoid ground loops (which on my old strat meant reworking the whole wiring harness). (I also was conscious to minimise tape overlap and to keep DC-continuity throughout the shield and keep it at an absolute minimum - a handful of ohms). Worth doing it if you have an old beater you don't mind changing. I wouldn't do it on my newest Fender Customshop signature model LoL (but that one came from the factory with noiseless pups)

[Willabe]

Thank you Pete. 

I have a new Fender Aluminum shielding plate for the back of the pickguard, it's fairly heavy gauge. And I used the shielding paint thru out the main cavity, cavity back, cavity sides, 1/4" jack cavity.

I'll watch the wiring harness grounding.

[Latole]

I use both from Stew Mac ; copper tape and conductive paint. Both work great.

As I often read on too many forums, some people use tools or stuff they don't know how to.

People know enough to talk about it but not enough to do a good job.

[Willabe]

Sure, now I find it for $15 instead of $25.      

https://www.eio.com/products/mg-chemicals-841ar-15ml-nickel-conductive-coating?variant=15313580621890&msclkid=44e9371644e11546ecd55580e151c4ba&utm_source=bing&utm_medium=cpc&utm_campaign=

[Willabe]

I bought a new trem/bridge assembly from Wudtone, their in Wales, UK. All cold rolled steel. If/when I get another Strat, I'll probably get a Callahm cold rolled steel trem/bridge. Pre 65' Fender Strats all used cold rolled steel for the trem/bridge assemblies. They later went to zink.

2021 WUDTONE CP VINTAGE 50s (NICKEL) TREMOLO ASSEMBLY - Wudtone Custom Guitar Innovation | Hardware & Finishes

And a new neck plate and screws. The neck plate is 2.5mm and made from "cutlery grade stainless chromium steel." Very strong, not those thin plates they use now. 

The screws are a little fatter in diameter and have less tapper down to the screw tip/point. Really grabs the neck now!

Wudtone Neck Plate and Screws - Wudtone Custom Guitar Innovation | Hardware & Finishes

These 2 things have drastically improved this guitars sound. Easily at least 20% more harmonics. A very noticeable amount of sustain was added. Plus it's fuller/thicker sounding, bass and low mids are cleaner/clearer/tighter with more hi end chime (those extra harmonics). It has more depth to the sound, more 3d. And it's much clearer sounding across the spectrum from hi to low sounding, really rings like a bell now.

I know it sounds like the same stuff they say on forums and that the companies put in their sales pitch, but it's the best I have to describe it. I would have loved to have had these up grades 30 years ago when I was playing gigs. But they didn't exist back then and I couldn't afford a real pre 65' Strat.   

I knew adding these upgrades would improve the guitars sound, but I didn't know how much and how encompassing overall it would be. Really, really surprised me. I don't want to make it sound like it's a 100x better, but it is sooooooo much more pleasing to the ear now. And almost all Strats could always use some extra sustain.           

Pricey upgrades, but it's worth every penny to me. Such a difference in tone and sustain.

And I haven't changed the PUP's yet! 

I bought a used set of Sliders SRV Strat PUP's. He's an Aussi builder, he only hand winds a couple sets a day? Tone Quest Report mag flipped over his PUPs. I have a couple sets of Sliders HB's to try out too. His PUP's are NOT hot/overwound PUP's. Their pretty hard to get and pretty pricey. I wanted his 59' set, but I grabbed what I could get.   

He says the SRV set is just a little cleaner, a little clearer. And that's what I like, clarity, so I might prefer these to the 59' set? If I want distortion, the amp and/or a pedal can do that. 

[Willabe]

And while I'm at it, it gets a full face lift. 

I found a Tortoise pick guard I really like. It has more contrast, more broken up with lighter colors and yellow. And I got all new PUP covers/knobs/PUP switch tip, vib arm tip, in a vintage cream. The pick guard and PUP covers/knobs/PUP switch tip, vib arm tip that came with it were all white.

Looks way better now to me.

IKN 11 Hole Strat Pickguard for 3 Single Coil Pickups, come with Pickguard Screws, 4Ply Brown Tortoise Shell : Musical Instruments

[pdf64]

… wired to avoid ground loops …

I’ve not managed to get my head around how a ground loop can occur in this context.
Has anyone come across a technically coherent explanation of a mechanism by which it may occur, anywhere on the web?

[Willabe]

It went on pretty thick with just 1 coat, 2 - 0.4fl. oz/15ml bottles. After a week of drying I get 2.8ohms from the furthest points of the neck and bridge PUP's, and 4.7ohms from the furthest part of the neck PUP to the furthest part of the 1/4" jack route.

I put a 2nd coat on just to see what would happen.

With my meter zeroed out, now I get 0.3 ohms from the furthest points of the neck and bridge PUP's, and 2.2 ohms from the furthest part of the neck PUP to the furthest part of the 1/4" jack route. And only 1.3 ohms from the 1/4" cavity to just on the other side of the wood wall between that 1/4" jack rout and by the bridge PUP.

So I'll locate the ground lug that will be screwed into the wood to connect to the shielding paint close to where the hole is for the wires to go through to the 1/4" jack by the treble end of the bridge PUP.   

[Willabe]

Progress report. 

The 2 coats of the nickle shielding paint worked great. (Link above for the paint I used.) Every bit of ~75% quieter. Very satisfied. Turn to the right position and it's almost dead silent. I have to really strain/focus to hear any humm/buzz, and then it's very, very slight.

I checked for resistance between the shield plate and the cavity shielding and it's ~1.1ohms to 0.1 ohms depending where I test.

I checked for resistance on the original old (1986) pickguard aluminum shield plate and the pots. After some ~36 years there's ~0.1 ohms resistance from the back of all 3 pots to the far end of the shield. I was very surprised. I don't recall ever taking those pots out and cleaning the contact points, star washer/aluminum shield plate.

So to me that says the change is because of the shielding paint and not new/clean contact at the grounds. 

Very happy I did it. 

[Willabe]

Does wiring the 2nd tone pot on a Strat as a blend control add any extra load to the PUP's?

Would the blend pot effectively be in parallel with the volume pot? (All 3 pots in my Strat are 250K.)

Right now I have it wired up as master volume/master tone/blend. I thought I try it and see if I like it, so far I do, but I'd have to disconnect the blend pot to listen for any difference in sound.

Thank,  Willabe

[pdf64]

I don’t think it introduces any additional loading.

[Willabe]

Is the standard 5 way switch on a Strat a 2P3T On/On/On?

[acheld]

Is the standard 5 way switch on a Strat a 2P3T On/On/On?

I thought it was on and on and on, like On/On/On/On/On 

Think of it more like a selector.  Just looking at it is not helpful (to me).

Easy to read diagram here:  https://www.stewmac.com/video-and-ideas/online-resources/learn-about-guitar-pickups-and-electronics-and-wiring/5-way-crl-lever-switch/

[Willabe]

I thought it was on and on and on, like On/On/On/On/On 

 

Yes, I meant to write 3 way.

Thanks   

[G._Hoffman]

I decided to shield my Strat cavity, should have done it years ago.   

I read some complaints about Stewmac shielding paint being high in resistance when checking with a meter and some copper tape that was supposed to have conductive adhesive on the back but didn't. Other guys had very good results with the copper taper or Stewmac conductive paint.      

So, I chose MG Chemicals 841AR nickel conductive paint instead. Pricey stuff but seems to have worked very well?

I used a plumbers acid brush, cheap, short handle, disposable, to apply it. It went on pretty thick with just 1 coat, 2 - 0.4fl. oz/15ml bottles. After a week of drying I get 2.8ohms from the furthest points of the neck and bridge PUP's, and 4.7ohms from the furthest part of the neck PUP to the furthest part of the 1/4" jack route. I used a Q tip to apply the paint in the 1/4" to main cavity hole. It worked pretty good.

Does that sound low enough in resistance? I read where other guys that used copper tape or Stewmacs paint were getting anywhere from 200ohms to 50ohms. That seems high to me. Some guys didn't even have continuity with the copper tape. 

After I put it back together, I'll decide whether I'll change out the cloth PUP hook up wire for shielded wire. I want to hear how much difference just the conductive paint made first. 

Willabe

https://www.amazon.com/MG-Chemicals-Nickel-Print-Conductive/dp/B01M28SRH0/ref=pd_lpo_1?pd_rd_i=B01M28SRH0&psc=1

You are overthinking this.  Like, a LOT. 

Resistance with a meter isn't important.  A Faraday cage doesn't need all that much conductivity - it just needs some.  I've been using the Stew-Mac paint for decades, and it works perfectly.  The only reason I don't recommend it to most people is that you are very unlikely to ever use it up, and it seems wasteful.  Before we started using the paint, we used aluminum foil and spray adhesive (and let me tell you, the Stew-Mac paint is SO much less messy!!!!!!!)  It worked great.  It's kind of like a anti-static work-mat - you put your multi-meter probes 1/4" apart, and you'll read infinite resistance, but it still works perfectly, because the amount of conduction required is just SOME conduction.  A Faraday cage doesn't work down to quite that low, but it really doesn't need much.

A lot of people confuse theory with real world performance.  I promise you, a soldered copper cavity shield doesn't provide any better results than spray adhesive and aluminum foil.  Even if the adhesive reads as a complete insulator at DC, it will look like ground at any frequency we are worried about blocking out.

So, yeah, don't worry so much about it.  It really isn't that complicated.

[G._Hoffman]

Is the standard 5 way switch on a Strat a 2P3T On/On/On?

Yes, with make before break connections, and intermediate stops.

[G._Hoffman]

Does wiring the 2nd tone pot on a Strat as a blend control add any extra load to the PUP's?

Would the blend pot effectively be in parallel with the volume pot? (All 3 pots in my Strat are 250K.)

Right now I have it wired up as master volume/master tone/blend. I thought I try it and see if I like it, so far I do, but I'd have to disconnect the blend pot to listen for any difference in sound.

Thank,  Willabe

Of course, but not in any meaningful amount.  Remember, your typical strat pickup is 8k, and a couple 250k pots in parallel is still WELL bigger than the 10x rule.  If you want to be super fussy about it, use a 1meg pot.

[G._Hoffman]

Progress report. 

The 2 coats of the nickle shielding paint worked great. (Link above for the paint I used.) Every bit of ~75% quieter. Very satisfied. Turn to the right position and it's almost dead silent. I have to really strain/focus to hear any humm/buzz, and then it's very, very slight.

I checked for resistance between the shield plate and the cavity shielding and it's ~1.1ohms to 0.1 ohms depending where I test.

I checked for resistance on the original old (1986) pickguard aluminum shield plate and the pots. After some ~36 years there's ~0.1 ohms resistance from the back of all 3 pots to the far end of the shield. I was very surprised. I don't recall ever taking those pots out and cleaning the contact points, star washer/aluminum shield plate.

So to me that says the change is because of the shielding paint and not new/clean contact at the grounds. 

Very happy I did it. 

A bit of dirt isn't going to matter much by the time you get to audible AC range frequencies.  At worst, it's a very low value cap in an RC circuit with R=near-enough-0.  Do the math.  Shielding guitars is VERY forgiving.  Just like everything else in guitar electronics.

[G._Hoffman]

I shielded an old '89 American Series strat I had using Aluminium foil tape. It did reduce the hum quite noticeably, and I kept it for about 15 years after that and used it a lot in venues where there were PAR light cans rigged up etc, and it did help keep hum down quite a bit (and I sold that geetar a couple of years ago still with the shielding intact - but I sold it for other reasons - needed a re-fret). But to do it properly/effectively you have to shield the whole cavity (sides, back and behind the scratch-plate) and ensure the ground returns for the guitar are all wired to avoid ground loops (which on my old strat meant reworking the whole wiring harness). (I also was conscious to minimise tape overlap and to keep DC-continuity throughout the shield and keep it at an absolute minimum - a handful of ohms). Worth doing it if you have an old beater you don't mind changing. I wouldn't do it on my newest Fender Customshop signature model LoL (but that one came from the factory with noiseless pups)

Honestly, at the current levels inside a guitar, ground loops aren't a concern.  They all end up at the jack no matter what.  You do need to make sure your shielding is all grounded, but beyond that it is way more forgiving than you expect.

[dude]

to do it properly/effectively you have to shield the whole cavity (sides, back and behind the scratch-plate) and ensure the ground returns for the guitar are all wired to avoid ground loops (which on my old strat meant reworking the whole wiring harness).

I sheilded my start with Stew/Mac copper tape, seemed to work ok but over time I have changed p/u's, switch and jack just leaving the tape as it was but I now have major hum and have to walk away considerable distance from my amp to find a spot where things are quite.
Ground Loop in an amp I understand but not so much in shielding a strat, what should I watch for?

[pdf64]

Single coils pick up hum from magnetic fields, you’d have to step into a mumetal booth, or fit a humbucking coil, to get rid of it.

Shielding deals with higher frequency hash, buzz, static carried by electric fields.

Regarding ground loops and guitar wiring, I think the main thing to watch out for is dodgy explanations 

[Latole]

I use both Stew Mac copper shield tape and conductive black paint many times with success.

Like many tools, you must know how to use it. If you don't, they did not do the job.

[rake]

Copper conductive paint used for electroplating plastics works really well.
Downside? It's a bit more expensive.

https://caswellplating.com/copper-conductive-paint-4oz.html