potting without pro setup?

[Rodent]

If you are making pickups for customers I think it makes a lot of sense to pot them unless requested otherwise.

Exactly. I recently had a set of J bass coils squeal when the customer was playing a loud live gig and had his bass right in front of the speakers. That particular set was perfect at all but high volumes. Giving the set a dunk in CPES to bond any naughty wraps solved the prob. I just may be dunking all future orders to avoid this happening again.

latest batch of J coils ready for potting



I used a couple pieces of scrap lumber to form a small rectangular area, and then draped several layers of industrial grade plastic wrap over it to form a pool just large enough to hold a J coil. 5T ea of parts A & B we enough to fill the pool so I could submerge a coil, and bubbles stopped emanating from the bobbin hole after about 15 seconds. Out of the pool and onto the drain table for a 24 hour cure, and these were ready to load into covers and package up.

[big_teee]

I wax pot all pickups.
On some overwound SCs, like Strat bridge pickups, I tape the coil with humbucker tape, after potting.
That solves any loose wrap problem, and makes the pickups more rugged with novice installers, and the tape is hidden under the cover.
Wax potting is so easy and effective, I'll pass on Lacquer and Epoxy potting.
YMMV,
T

[Rick Turner]

I wax pot my humbucker coils with a crock pot doing the melting. I submerge the coils, then put the pot into a low temperature vacuum oven and pull about 27" of mercury, let it off, and then epoxy pot those in humbucker no-hole shells. Yeah, wax and epoxy. I use the oven just because I have it, but at some point I'll just put a gasket vacuum seal on the crock pot and a vacuum hose to the lid.

I'm about to re-visit and update some of my early days Alembic pickup designs, and I'll adapt the wax + epoxy or urethane potting systems to that. At one point, we were using magnet wire that had an alcohol soluble adhesive coating, and we'd spritz the coils with denatured alcohol to bond the wire.

[big_teee]

Wax Potting is something that so many try to make a complex issue.
It's not, it's just wax, pot at whatever level you prefer.
The most important thing, is temperature.
On most pickups you can get by with 130-145F degrees. Some plastics are very heat sensitive.
On My humbuckers I wind tightly, and paper tape the coils well so it keeps most of the wax out.
I'm mainly concerned about potting the metal parts, like covers and baseplates, after assembly!
If you want the coil completely wax saturated, you can pot the indiviual coils before taping, and before assembly.
On Fender type open coils I pot completely, I leave them in the pot for a minimum of 10 minutes.
Longer is fine, if you get busy, it doesn't hurt anything.
I have some loud players that use lots of Gain, no complaints with my pickups being microphonic.
Vacuum potting is faster, and fine, but not required.
T

[Rodent]

I don't find wax potting complex. For me it's as simple as not liking the smell of hot wax combined with the lack of ventilation to take the wax vapor out of the workshop

I may someday add the capacity to wax pot, but I don't see that happening in the coming weeks.

[big_teee]

Fair enough.
Options are good. Whatever works for you.
My workshop is outdoors, so hot in summer and cold in winter.
Lots of ventilation here.
In the Beginners/Hobbyist Area I try to give some cheap inexpensive options, and alternatives, rather than all the full blown gear the pros use.
Point out from time to time that having a assembly line environment is not required to make a few pickups!
I wound on a cordless drill and potted my pickups in a coffee can for a long time.
Finally graduated to a ready made winder, and a Crock pot for potting pickups.
YMMV,
T

[buddha0709]

Fair enough.
Options are good. Whatever works for you.
My workshop is outdoors, so hot in summer and cold in winter.
Lots of ventilation here.
In the Beginners/Hobbyist Area I try to give some cheap inexpensive options, and alternatives, rather than all the full blown gear the pros use.
Point out from time to time that having a assembly line environment is not required to make a few pickups!
I wound on a cordless drill and potted my pickups in a coffee can for a long time.
Finally graduated to a ready made winder, and a Crock pot for potting pickups.
YMMV,
T

it worked out good for me that I bought the wife a paraffin foot bath/spa thingy and she only used it once then it sat in the closet for years. It works perfectly for me, And it's safe for human hands and feet too.. I think I read someone else here uses one too...They get to about 130ish degrees.
They are only $30ish and normally come with a couple blocks of paraffin.

[Rick Turner]

A crock pot at the Goodwill qualifies for pretty cheap and usable at the pro level as well as home hobby work. I guess the real issue is vacuum or no vacuum. Note too that it's not the vacuum that does the work of fully impregnating the coil; it's the atmospheric pressure when you release the vacuum.

[Chuck H]

Note too that it's not the vacuum that does the work of fully impregnating the coil; it's the atmospheric pressure when you release the vacuum.

Nah... It's the vacuum. You can see the bubbles flow and rise as you increase the vacuum pressure. They evacuate the coil to fill the empty space left behide by the evacuated space. Of course i's atmospheric pressure that allows the potting medium to re enter the coil. But as long as the coil is submerged in the medium that seems like a given.

[Steve A.]

Pickups have been cut open that were potted without a vacuum and hardly any of the wax penetrated all of the way to the middle of the coil. Or so I have heard. Without a vacuum I guess that would solidify the windings on the outside of the coil but tightly wrapping tape around the coil would probably accomplish the same. I forget who it was here who suggested using teflon tape but I like it because it can usually be removed without tearing the coil wire. And electrical tape on top of the slug coil can eliminate vibrations against metal covers.

I try both of those measures first before getting out my wax double-boiler (made up from two Goodwill pots that nested together properly.) I don't play high gain or at ear-shattering volumes so I prefer the sound of unpotted pickups- I think that they have more "character." I know that some of the boutique winders give you a choice between potted and unpotted.

I guess I should mention that I'm a pickup customer not a pickup maker in case anybody doesn't already know that.

Steve

[big_teee]

Wax won't penetrate a covered Taped humbucker much, which is fine.
I'm mainly trying to pot the metal parts like mentioned earlier.
That is how I like mine potted.
Just pot them to whatever degree you want.
It's individual preference.
T

[Bruce Johnson]

I'm still using epoxy for both stages of potting. I use the CPES epoxy to glue all the wires of the coil together, dabbing it on while the coil is hanging over a drip pan. I usually let them dry 24 hours. I've cut a couple of test coils apart and the CPES completely soaks in and locks all the wire together into a semi-soft lump. That's what I want. Then, the completed coil assemblies and shielding shell parts are set into a silicone rubber mold and are encapsulated in black West Systems epoxy. That provides the hard outer protective shell. It's permanent and forever. I've been building my pickups like that for about 8 years, and I haven't yet had a pickup fail for any reason.

[big_teee]

Whatever works, but that seems like a lot of extra effort.
However for a custom instrument, I guess it's worth it?

[Rick Turner]

Actually it is the atmospheric pressure forcing the wax into the depths of the coil. The bubbles just represent air leaving, not necessarily wax entering. It's a vacuum! You won't get any more wax impregnation in the vacuum that you would doing it with no vacuum at all. You'll get some, but nothing quite like what happens when you get that sudden 15 PSI pushing molten wax into voids.

And the whole issue of damping vibrating other metal components is very real. It's amazing how those "non-magnetic" parts can vibrate just enough to cause major squeal at high gain. You've got dynamic eddy currents there coupling like mad to the coil(s).

[big_teee]

The only pickup type I've had issues with potting is the Tele Bridge pickup with the steel baseplate.
The baseplate has to potted where it is immobil, or it will probably be microphonic.
I have a potting method that takes care of that now.
Some modern Tele bridge SC pickups have screws on the bottom to help keep the pickup baseplate stationary.
T