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Post by frets on Feb 5, 2021 12:32:48 GMT -5
Hi Unreg, 😁 I can’t upload photos in PM’s. I think it’s because I use my phone to post everything. Anyway, here are the copper lugs I was referring to. You can find them in the electrical section of a hardware store. Just ask a guy.  |
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Post by unreg on Feb 5, 2021 13:22:29 GMT -5
hi frets! Those don’t look like the loop is big enough to fit around a CTS A500K shaft... I need something to solder the ground wire to the pot casing so the pot’s casing will be grounded... since my paint mixture’s surface ended up being between 1200 ohms and 400 ohms. The lowest 400 ohms is still not conductive enough for the pot casing to be grounded, right? My soldering iron seems to be too hot to solder safely to a pot’s case. I just ordered a new long shaft CTS volume pot bc of the damage my poor soldering skills/too hot iron did to my current volume pot. Thank you so much for the photo and star grounding idea... 😁 I may try that bc I’ll probably need to change out my paperclip star ground since the current paper clip is not long enough to receive solder for two more grounding wires, one for each of my two pot cases. |
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Post by newey on Feb 5, 2021 13:39:05 GMT -5
I just ordered a new long shaft CTS volume pot bc of the damage my poor soldering skills/too hot iron did to my current volume pot. Are you using a heat sink of some sort when soldering? No, they don't, but bigger ones are readily available. But also bear in mind that, if you're accepting that the conductivity of the shielding paint is good enough for your cavity shielding, it also should be good enough to ground out the pot cases through contact. Or, at least, you can measure the resistance between the shielding paint and the pot case to see if it is showing equally low resisitances. I'd at least try that before worrying about using lugs for grounding connections. Keep in mind that, while grounding pot cases and switch cases is a "best practice", it is probably unlikely that your pots are significant sources of noise. You could probably get away with not grounding the pot cases at all, and I'd bet you wouldn't notice any difference in noise if you did an A/B comparison. |
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Post by unreg on Feb 5, 2021 15:35:30 GMT -5
Are you using a heat sink of some sort when soldering? I have no idea how to use a heat sink while soldering. 🙂 No, they don't, but bigger ones are readily available. Was hoping to hear that, thank you newey! 🙂 But also bear in mind that, if you're accepting that the conductivity of the shielding paint is good enough for your cavity shielding, it also should be good enough to ground out the pot cases through contact. But, that’s the thing... the painted surface of the cavity seems to be not conductive enough; and but, I believe frets has let me know that all the 4 layers of graphite have created enough graphite barrier to block the electrical noise disturbances. Or, at least, you can measure the resistance between the shielding paint and the pot case to see if it is showing equally low resisitances. I'd at least try that before worrying about using lugs for grounding connections. Keep in mind that, while grounding pot cases and switch cases is a "best practice", it is probably unlikely that your pots are significant sources of noise. You could probably get away with not grounding the pot cases at all, and I'd bet you wouldn't notice any difference in noise if you did an A/B comparison. An A/B comparison? Sorry for not understanding. 😔 If the shielding-paint’s surface runs between 1200 ohms-400 ohms and if your test between the shielding paint and the pot case shows me an equal resistance, then that resistance would definitely not be low enough for high conductivity, right? (removed word mistake) |
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Post by blademaster2 on Feb 5, 2021 16:37:43 GMT -5
To me the benefit of the lug is that you can solder the ground wire to it before it gets installed, so the soldering heat is no longer a worry.
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Post by newey on Feb 5, 2021 19:49:26 GMT -5
To me the benefit of the lug is that you can solder the ground wire to it before it gets installed, so the soldering heat is no longer a worry Exactly. But my point is that, if the shielding paint is conductive enough for the cavity shileding, is it not therefore also conductive enough to ground the pot shells, via contact at the shaft, no lugs/wires needed. I've never used shielding paint, I use the copper tape with the conductive adhesive (This allows overlapping the tape strips without needing to connect them togehter electrically.) With the tape, I use that as the grounding for the pot shells and switch frames (checking with the meter for a good connection). It's like unreg is willing to trust that his shielding paint is good enough for one purpose but not for the other. I'm not saying that the shielding is faulty, I agree with frets, should be OK. But if it's OK for a shielding ground, then it's OK for the pot shells, provided good physical contact is made. Keep in mind that "ground" is not an absolute, but a difference in potential. I'd be interested to hear from one of our members who just happens to have the guts of a stock Fender Strat exposed, Fender has been using shielding paint for years (although I'm not sure they actually attach it to a grounding point!). So, let's get a measurement on how much resistance Fender considers "ok" . . . |
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Post by unreg on Feb 5, 2021 23:08:33 GMT -5
To me the benefit of the lug is that you can solder the ground wire to it before it gets installed, so the soldering heat is no longer a worry Exactly. But my point is that, if the shielding paint is conductive enough for the cavity shileding, is it not therefore also conductive enough to ground the pot shells, via contact at the shaft, no lugs/wires needed. It's like unreg is willing to trust that his shielding paint is good enough for one purpose but not for the other. I'm not saying that the shielding is faulty, I agree with frets, should be OK. But if it's OK for a shielding ground, then it's OK for the pot shells, provided good physical contact is made. , you understand me! 😀 I am willing to trust that my 4 layers of shielding paint is good enough for shielding outside noise; but, my head contains swirlings from that thread where thetragichero said my lofty first coat of paint ohm readings weren’t conductive enough for him. And other voices like frets, who said her shielded painted cavities returned readings of about 11 ohms resistance. Keep in mind that "ground" is not an absolute, but a difference in potential. So... you are saying that the 11 ohm reading could be the same as my 1200-400 ohm readings?  I'd be interested to hear from one of our members who just happens to have the guts of a stock Fender Strat exposed, Fender has been using shielding paint for years (although I'm not sure they actually attach it to a grounding point!). So, let's get a measurement on how much resistance Fender considers "ok" . . . Great idea! 😀 Thank you newey sir! |
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Post by ashcatlt on Feb 6, 2021 11:44:42 GMT -5
I’ve measured fenders (well...squiers) before, and the readings were very low. If it would have come up at 400Ω, I’d have added foil.
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Post by unreg on Feb 6, 2021 20:40:56 GMT -5
Today, I acquired 3 of the 4-gauge copper lugs with a 3/8” diameter hole. I’m going to place one at the base of each inverted pot... my guitar is rear access only so that’s how it seems to me... and one will be soldered to the end of the star ground paper clip, and the two new ground wires will be soldered to that lug, which will be also attached to the wall with a screw. Decided to not destroy my paper clip; rather, just add on to it. The guy at ACE said I could crimp the lug to increase the electrical connectivity... maybe I’ll do that too... Thank you so much frets! 😀 |
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Post by unreg on Feb 12, 2021 15:36:28 GMT -5
frets and newey, you’ve both made me really think about my outer 400 ohm -1200 ohm layer of shielding paint. I have and agree with you frets that all the not-conductive-enough layers of shielding paint contain enough total graphite to block unwanted electrical interference from the outside. Do you both feel the copper lugs are pointless bc the separate layers of graphite-paint’s graphite are touching each other and therefore it’s conductive enough to relay the ground signal from the star ground paperclip to the pots... even though the multimeter does not recognize a conductive path? newey said something like ground requires relative conduciveness. Not exactly that... but it was kind of hard for me to understand. My replacement pot arrived today, so I am just trying to fully understand what you all were trying to teach, before my guitar is changed again. Thank you for reading... 😊
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Post by frets on Feb 13, 2021 16:05:57 GMT -5
Hi Unreg,
In my opinion, you don’t need the lugs. You have thoroughly shielded the cavity, you’ve done more than most guys regarding EMF. I say your good to put everything back in and get rockin’. 💃🏼🕺🏼🎸🎸🥁🥁🎹🎹🎼🎼🎤🎤
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