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Epoxy Potting vs. Wax Potting?

FunkMetalBass

FunkMetalBass

Aug 5, 2005
7,243
92
Phoenix, Arizona 85029
music.joedub.net
Disclosures
Endorsing Artist: J.C. Basses
#1
I've always wondered by I got a lot of noise from my pickups, but I figured it was just the nature of single coils.

In taking my 8-string to the tech today and talking about proper copper shielding, he told me that my pickups may need to be wax potted. I looked it up, and it turns out that they were epoxy potted, but not wax potted.

Has anybody ever heard of this? Are there pros/cons to wax potting vs. epoxy potting?
 
#3
FunkMetalBass said:
Has anybody ever heard of this?
Click to expand...

There are too many epoxy potted pickups in the world for me to even begin counting.
EMG is an example.

As mpm32 stated, epoxy is pretty much permanent. If the pickup should fail internally, it's as good as trash, as it cannot be repaired without destroying the coil to get past the epoxy.
It's very rare that you have a pickup short out or something though.
 
#6
Some epoxy potted pups can be saved. I've got some Peavey T-40 pups that I've stripped of the epoxy and am going to rewind. Mind you, it took several hours to strip 2 pups and not damage the plastic bobbins.
 
#8
R. Laevinus said:
How did you manage that? The epoxy I've met in my life is pretty much rigid once set.
Click to expand...

Peavey's epoxy sets up like like a hard rubber. Plus, it being 30 years old might have something to with it being more workable. I haven't messed with any modern pickups, so the T-40s might be an exception. It did take me awhile to find the right tool to use. I ended up using a cheap paring knife I got from Wal Mart. It had just the right sized blade, was flexible and had the right degree of dullness-sharpness. I used a dull x-acto too. The T-40s have a metal cover. It comes off fairly easily. Once it's off, you just start shaving off the epoxy. A pup with a plastic cover would an interesting challenge. I'd look for a weak spot and start there. Patience is the key.
 
#9
xaxxat said:
Peavey's epoxy sets up like like a hard rubber. Plus, it being 30 years old might have something to with it being more workable. I haven't messed with any modern pickups, so the T-40s might be an exception. It did take me awhile to find the right tool to use. I ended up using a cheap paring knife I got from Wal Mart. It had just the right sized blade, was flexible and had the right degree of dullness-sharpness. I used a dull x-acto too. The T-40s have a metal cover. It comes off fairly easily. Once it's off, you just start shaving off the epoxy. A pup with a plastic cover would an interesting challenge. I'd look for a weak spot and start there. Patience is the key.
Click to expand...

Yeah, it sounds like that was the exception, not the rule.
Most epoxy potting is permanent.
 
#11
FunkMetalBass said:
So given that my pups are microphonic, I'm pretty screwed unless I attempt a hand re-wind?

Joyous.
Click to expand...

Such is life. However, IF you can munch enough of the epoxy away to expose the coils without actually damaging them (be aware that the likelyhood of such damage can be very high) you can soak them in hot wax that may seep in an stabilize the windings to eliminate the microphonics. Just start with the assumption that the pickups are already trash and then consider any success you have a freebie.
 
#12
bassbenj said:
Such is life. However, IF you can munch enough of the epoxy away to expose the coils without actually damaging them (be aware that the likelyhood of such damage can be very high) you can soak them in hot wax that may seep in an stabilize the windings to eliminate the microphonics. Just start with the assumption that the pickups are already trash and then consider any success you have a freebie.
Click to expand...

Wax potting under vacuum might help too.
 
#14
bassbenj said:
Such is life. However, IF you can munch enough of the epoxy away to expose the coils without actually damaging them (be aware that the likelyhood of such damage can be very high) you can soak them in hot wax that may seep in an stabilize the windings to eliminate the microphonics. Just start with the assumption that the pickups are already trash and then consider any success you have a freebie.
Click to expand...

Well, I've emailed Clint (Searcy Stringworks) to see if there's anything he can do. After all, if the pickups are microphonic, epoxy potted, and haven't been touched since I got it.

I wish I'd known as much about pickups then as I do now so that I could have figured out this issue a year and a half ago and not just this last week.
 
#15
Are the pickups microphonic, or they just hum?

If you are getting squealing when you get near your amp, that's microphonic.

Potting doesn't stop single coil noise though. Potting just makes the coil solid so it doesn't vibrate and feedback.

I know Clint, and he does wax pots his pickups.

If your tech thinks that wax potting pickups gets rid of hum, get a new tech.
 
#17
SGD Lutherie said:
That was probably rubberized epoxy. Lane Poor also used that.

Pickups should be wax potted before the epoxy. The epoxy alone doesn't work very well to stop microphonics.

I wax pot my coils before the epoxy goes in. So does EMG.
Click to expand...

Too bad Peavey didn't wax pot before epoxying. It would have made repairs much easier. I have two pups where the epoxy shrank and broke the wire at the solder post. What wire that was accessible was very brittle and broke at the touch. Sure would have been nice to remove the epoxy, unwind a winding or two and re-solder it.
 
#18
xaxxat said:
Too bad Peavey didn't wax pot before epoxying. It would have made repairs much easier. I have two pups where the epoxy shrank and broke the wire at the solder post.
Click to expand...

That's one of the reasons to use rubberized epoxy.

I avoid that by not soldering to posts or eyelets. All my coil leads go to hookup wires and everything is taped up prior to the epoxy being poured in.
 

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