Here comes a different method to shield a bass cavity after shielding bass cavity with copper foil tape for a few years.

A few facts about cavity shielding:

- Why shielding?   Poorly shield or no shielding instrument tent to attract more hum and noises.  

- Grounding hum or shielding hum ?     if the hum reduce or disappear when touching any metal components (hardwares, strings) then it's mostly shielding issue.   If there's hum no matter touching the string or not, it could be grounding issue, or sometimes it's your single coil pickup hum.  Check your wiring.   

- how does shielding work?  create/build a box around the electronic components so it attracts unwanted interferences and dump that signal to ground before they get into  your bass signal.  

- Copper foil tape or shielding paint ?  doesn't really matter, whatever that comes in handy.   but after using foil tape for years, challange for me are:
1. it takes a long time to get neat and professional result
2. sometimes the tape doesn't stick well, there are other well taped cavity that came lose afterward and causing issue.  
3. sometimes the tape makes fitting more difficult with its extra thickness.  A several time I had issue pushing the pickups back into the cavity, and often the tape got ruined.

Anyways, 6 years after shielding another 10ish bases, I'm going with shielding paint today , it's not much more diffcult, just require more preparation and I'd say the time taking is about the same compare to taping cavities.    I went with carbon shielding paint in aerosol can, for a thinner, cleaner and more professional look.  

1. remove most parts from the body.  

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 2. Mask the entire body, and bring it outside to spray.  Please wear a respirator  
*masking tape and nitro lacquer body don't always work well with each others.   be extremely careful with the tape you put onto your nitro finish guitar body!!

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 applied 2 wet coats, wait 20mins in between and let it sit for 2hrs after.   blow drying would help, but having some patient would work better.  

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 peel off the tape and clean up the edges a bit

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 connect all cavities to the ground bus.  (i don't see the need of shielding the battery compartment)

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 put the wirings back

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this bass is now dead silent except you only turn on 1 single coil at a time .   I feel more than comfortable to take this guy out to any kind of gig .   

amerteur builders often don't pay attention to shileld their instrument properly when their environment is not causing problem .   but if you're building something for people get paid by playing, it's better to have their tool prepared for any kind of situations.   

*Fender CIJ Marcus Miller signature Jazz bass is being served