Pickup epoxy

jworrellbass · #1 09-10-2009, 04:37 AM

I've been tring to find epoxy for pickup potting, what do you guys use?

TheSuzie · #2 09-10-2009, 04:50 AM

Back before I became too ill to work with chemicals I used either garden variety epoxy or 5 minute epoxy and thinned them down with rubbing alcohol. I am getting my old bass back (on the UPS truck now). It has been at least a half dozen years since I potted those pickups using 5 minute plus alcohol.

I used to use the same sort of mixture on electric motors many years ago. I usually used the slower drying stuff for that because it seemed to be more temperature resistant.

Peace,
S

jworrellbass · #3 09-10-2009, 04:59 AM

I'm sorry that you are ill, I hope you are not in pain.

As far as the 5 minute epxoy are you referring to the stuff that comes in a tube? Like Gorilla glue? If so how do you thin it with alcohol and apply it to the pups?

TheSuzie · #4 09-10-2009, 05:36 AM

Just to be clear, I have only done pickups once. Done dozens of electric motors, many RF coils etc, but only one set of PJ pickups.

The 5 minute comes in a double syringe, one plunger dispenses both the resin and the catalyst. I potted the coils right into the cover and used the solid covers - much easier. It is possible to do just the coil but I don't know about that and I didn't want anything at all to rattle around when I was done. No matter what you do you must be careful of the wires. If you use a cover where the pole pieces come through, you need to do something to keep the epoxy from leaking out and making a mess...maybe some sort of putty or something similar that will keep the mixture from leaking around the poles but can be picked out later or a bit between the top of the pickup and cover that can be left forever. That part I will leave to you or someone else. I never tried a pickup with adjustable poles, don't know how I would deal with that. As I said, I used the solid covers.

The epoxy needs to be thinned out a lot so it will penetrate the coils as much as possible.

Using a solid cover was easier as I could fill the cover part way with the epoxy mixture and then insert the pickup. A syringe can be used to fill the whole thing up so that the pickup is totally immersed inside the cover.

Epoxy set up in a layer this deep will take a long time to dry. Even if it is the five minute type. Using a lot of heat to speed things up is really not a great idea with a pickup but keeping the whole assembly a bit warm will help. Even after things appear to have hardened give it more time as there may be areas that have not fully hardened that could leak out and make a mess. If things are not too set the alcohol can be used for cleanup.

Practice on a junk pickup first. I would not try this on something that is important to you the first time. I was willing to buy new pickups if I failed when I did mine. They were so microphonic that I could not stand them but the potting totally fixed that. Always work in a well ventilated area.

Peace,
S

jworrellbass · #5 09-10-2009, 05:50 AM

Thanks a bunch, I let a friend use one of my basses that I built. He told me and then showed me how bad the microphonics where. When he moved the bass back and forward on his leg and you can hear it though the amp. And when he got closer to the amp it caused feedback. I potted the pickups with a liquid wax, it never hardened.

The other bass I put a hardener in the wax and it wasn't as bad, but you could still hear a little bit of the microphonics.

TC2112 · #6 09-10-2009, 07:39 PM

I would think the wax would set up before it could penetrate the coils if you didn't keep it warm. I use one of those candle warmers and a big candle jar. it takes it about an hour or so to melt the wax, but it never gets very hot, just enough to keep it melted. then I wrap the pigtail around a pencil and suspend the coil (no cover) in the wax for an hour or so moving it every so often so it doesn't get any bubbles or air pockets. then if you wanted to put some of the melted wax in the solid cover before you set the coils, then I guess you could. or shoot it in with a syringe. melted wax will stay soft for a while. I have never potted in a cover so I don't know if that would work with warm wax.
I have some Jazz pups I need to either pot or replace, so maybe I'll give it a shot

TheSuzie · #7 09-11-2009, 12:06 AM

The wax thing sounds interesting. I had read about it but used epoxy because that was what I was familiar with from my work as an electronics tech.

One thing I wanted to mention. When thinning epoxy with alcohol it is probably best to use alcohol with a low water content. Some garden variety isopropyl rubbing alcohol is only 70% alcohol and 30% water. I don't think I want my pickups sitting in a mixture that has so much water.

Peace,
S

Stealth · #8 09-11-2009, 03:37 AM

Personally, I'd avoid epoxy-potting the pickups because the pickup can hardly be dismounted and rewound afterwards - I'm all for the wax solution.

And, in case of wax solution, people seem to use the wax-parrafin mix the most, inside a double boiler placed on a normal stove. The double boiler regulates the temperature so it doesn't incinerate (and when it lights up, it REALLY lights up). Also - to the best of my knowledge - the pickup wax should solidify somewhat before you pull it out and let it completely harden. It's still wax, so don't expect it to be as tough as the pickup bobbin.

TC2112 · #9 09-11-2009, 05:21 AM

Quote:

Originally Posted by Stealth

Personally, I'd avoid epoxy-potting the pickups because the pickup can hardly be dismounted and rewound afterwards - I'm all for the wax solution.

And, in case of wax solution, people seem to use the wax-parrafin mix the most, inside a double boiler placed on a normal stove. The double boiler regulates the temperature so it doesn't incinerate (and when it lights up, it REALLY lights up). Also - to the best of my knowledge - the pickup wax should solidify somewhat before you pull it out and let it completely harden. It's still wax, so don't expect it to be as tough as the pickup bobbin.

I melt a bees wax candle in with the big candle the first time I melt a new one. By using a candle jar, most of those have lids so you can just pop the lid back on and have clean, pre mixed wax next time you need to do it. Plus you get cool red or blue wax to pot your pups in. I'll have to try leaving the pup suspended for a bit after I shut the candle warmer off. Seems like I would be pulling out a pretty big chunk of wax that way though. It usually gets a skin on it pretty quickly after I remove it from the wax, so there's not a lot of run-off, but what you say makes sense.

jworrellbass · #10 09-11-2009, 06:29 AM

I've tried to remove wire from a pickup after it's been potted, the thin wire breaks to easy. I would rather chuck it in to the trash than fix it. (Since I wound it)

I've looked around and found a few epoxy mixes that aren't that bad to work with. System 3 that woodcraft sells for one.