An alternative to potting humbucker pickup covers

Discussion in 'The Custom Shop' started by Danelectro, Jun 3, 2017.

  1. Danelectro

    Danelectro V.I.P. Member

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    I've never potted a set of pickups with wax because it looks like a mess that can't easily been undone. The method I've always used to prevent a pickup from squealing when attaching a cover is to apply a strip of scotch tape across the top of the slug bobbin, apply a bead of silicone caulk across the tape, then clamp the cover and solder it. The silicone dampens the cover and the tape prevents the silicone from getting into the crevices and square holes of the bobbin. Its effective at preventing microphonic feedback and relatively easy to do, although there have been a couple of times that I applied too much silicone and it squished over to the polepiece screws and made a mess. Additionally, I found that the scotch tape becomes very difficult to remove from the bobbin after its been in place for a long time.

    Last summer I received something or other that was wrapped in a very thin polyethylene foam sheet material. It got me thinking that this material might work well as a substitute to the silicone I had been using for dampening the pickup covers. I gave it a try and it actually works very well. There's no mess when installing a cover and if I decide to go uncovered at a later point I don't have to spend time cleaning the bobbins.

    This type of foam material comes in different thicknesses. The stuff I used has a nominal thickness of about about .030" and it compresses down to almost nothing. I simply cut a strip large enough to cover the slug-side bobbin, clamp the cover, and solder. So far, I've "potted" three or four sets of pickups this way and all have worked very well.

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    Last edited: Jun 3, 2017
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  2. Sct13

    Sct13 Premium Member

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    Good Idea!

    I usually use a few pieces of masking tape stuck to the cover...but those come off over time...this looks like a better solution
     
  3. jack briggs

    jack briggs Senior Member

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    vinyl electrician's tape
     
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  4. The Ballzz

    The Ballzz Senior Member

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    I wonder at the longevity of that foam. Probably pretty good, huh?
    Good Idea!
    Gene
     
  5. Hatefulsob

    Hatefulsob Senior Member

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    I don't have squeeling issues but I am annoyed by the microphonic "click" that happens if I let my pick touch the cover or more likely the plastic ring around unpotted pups. Will the above mentioned steps eliminate that or will potting be necessary?
     
  6. buckwild

    buckwild Premium Member

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    very cool! thanks for new idea Dan!
     
  7. GitFiddle

    GitFiddle Premium Member

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    Very cool. Thanks for sharing. I've done the tape and silicon on a set of 57s in a '99 historic. This looks like a very elegant solution.
     
  8. 5F6-A

    5F6-A Senior Member

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    Very interesting!
     
  9. Danelectro

    Danelectro V.I.P. Member

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    It sounds like that may be a grounding issue.


    I have no idea. If you ask an environmentalist how long the polyethylene will last, they'll probably tell you a thousand years. Seriously though, I imagine the foam will take a permanent set over time, but that doesn't necessarily mean that it will no longer have a dampening effect on the cover. If it does, you simply replace it.

    I tend to swap pickups occasionally in order to try out yet another "most accurate PAF clone ever" set of pickups. I like to maintain the same covers on each guitar as they are aged vintage-accurate looking covers (Throbaks and DMCs). Consequently, I do a fair amount of removal and re-installation of covers. Swapping covers on pickups potted with silicone isn't terribly difficult, but you do have to pry the cover from the pickup and then clean-up the residue afterwards. That was my inspiration to try this foam approach and it seems to be just as effective.
     
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  10. GitFiddle

    GitFiddle Premium Member

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    I have a 2016 Trad. I changed the hw from chrome to nickel. Instead of swapping covers on the 57s that came with it, I bought a set of ECP RD-59s with bare nickel covers. If I ever want to go back to the 57s I want to replace the covers with nickel. Who makes a good nickel cover to swap on a stock Gibson 57? (Proper fit, function and looks)
     
    Last edited: Jun 8, 2017
  11. Boss 302

    Boss 302 Premium Member

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    Interesting tip, thanks for sharing.
     
  12. jcsk8

    jcsk8 Senior Member

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    Attaboy.
     
  13. scovell001

    scovell001 Senior Member

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    I have a set of MK58 pickups wound by Haussel. There is a single piece of black foam (like draught excluder strip) stuck between the slugs & the screws on the top of the pickup, I imagine its doing exactly as you've demonstrated here, in a slightly more visually pleasing manner.

    :)
     
  14. d1m1

    d1m1 Senior Member

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    i once removed the cover of paf clone and on the cover was applied a strip of black isolating tape on over the slug bobbin. i guess for the same purpose.
     
  15. efstop

    efstop Senior Member

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    The foam will degrade over time and stick to whatever it's pressed against, but it takes a very long time. I had two mics nestled in foam, and the foam disintegrated, but stuck to the mic's brushed stainless steel casings. I didn't get it all off, but I haven't tried any solvents. Mind you, those mics were undisturbed in their cases for thirty years.
     
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  16. SparkyJones

    SparkyJones Senior Member

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    Painters tape works very well. I've used that many times in the past before I splurged and bought the 'proper' paper tape from Stew Mac.

    On a side note, some videos I've seen on you tube suggest to place a few dabs of caulk/adhesive on the tape before fitting the pickup cover. I find this unnecessary as the solder joint provides sufficient holding power.
     
  17. bulletproof

    bulletproof aka tarddoggy Premium Member V.I.P. Member

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    Damn good idea,brother!!:thumbs:
     
  18. kiko

    kiko Senior Member

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    Thanks for the tip. I myself use 2 layers of thin double sided tape applied to the slugs, works nicely!
     
  19. jbrew1977

    jbrew1977 Senior Member

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    Ha! I make that stuff where I work. All the way from full size rolls to converting it to sheets or pouches. Ours is polypropylene foam but it looks exactly like that. Kinda funny!
     
  20. Prostheta

    Prostheta Junior Member

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    Best of both worlds would be to stick foam inside the cover and apply a piece of tape over that to protect the pickup itself from the adhesive. We're talking hair splitting by this point I think.
     
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