Potting question

[tonedeciple]

I just made a P90 bobbin out of Maple and wound it with 8,000 turns of 43 AWG. I'm a bit concerned about dipping it into hot wax out of fear the bobbin might warp. Has anyone tried to apply CA glue to a coil as a way to dampen microphonics? I'm hoping it will soak in and dry super fast.

[David Schwab]

I just made a P90 bobbin out of Maple and wound it with 8,000 turns of 43 AWG. I'm a bit concerned about dipping it into hot wax out of fear the bobbin might warp. Has anyone tried to apply CA glue to a coil as a way to dampen microphonics? I'm hoping it will soak in and dry super fast.

It wont warp. I made a lot of pickups with wooden flatwork and potted them.

I tried CA once. I was a pain to work with, and didn't get all the way into the coil.

[tonedeciple]

The only problem is I used wood glue. I'm afraid the heat will cause the glue to break down. As it stands, the pickups are done, but not potted. If they don't squeal, I won't worry about it. If they do, I'll either glue the flatwork together with epoxy and pot as usual, or I may try an experiment where I'll brush some thinned rubber cement onto the coil after every 500 to 1000 turns. I tried brushing on some water-based lacquer during an initial test, but the moisture caused the flatwork to warp. Oddly enough, I think the water-based lacquer approach might work well with plastic bobbins.

[Jim Shine]

You can also use shellac. I use blonde flakes and mix it myself. Get a pipette and every couple hundred winds, apply a coat to the coils and let tack up before you start winding again. You can use lacquer as well if you are 100% certain the wire insulation will hold up against the thinners in it.

[David Schwab]

The only problem is I used wood glue. I'm afraid the heat will cause the glue to break down. As it stands, the pickups are done, but not potted. If they don't squeal, I won't worry about it. If they do, I'll either glue the flatwork together with epoxy and pot as usual, or I may try an experiment where I'll brush some thinned rubber cement onto the coil after every 500 to 1000 turns. I tried brushing on some water-based lacquer during an initial test, but the moisture caused the flatwork to warp. Oddly enough, I think the water-based lacquer approach might work well with plastic bobbins.

Be careful with rubber cement. The thinner might affect the insulation on the magnet wire.

I glue my pickups together with super glue, and I haven't had any problems with wax potting. You shouldn't have the wax too hot anyway.

Regarding shellac, I used vanish for a while, but had some issues with the pickups remaining microphonic, and it took forever to dry.

[Jim Shine]

Try the raw blonde shellac flakes with just enough alcohol to break the flakes down (I will sometimes leave the container open a while to let some alcohol evaporate). If it is thinned too much, you most of what you put on will evaporate. A heat gun on low heat will help speed up the drying process.

I try to avoid epoxies and glues. Most dry out over a long period of time and become brittle. They break from expansion and contraction, damaging the coil. This is what killed many of the original EMG pickups. This is why the earliest ones are scarce, most died in the 90's.

[Mike Sulzer]

Try the raw blonde shellac flakes with just enough alcohol to break the flakes down (I will sometimes leave the container open a while to let some alcohol evaporate). If it is thinned too much, you most of what you put on will evaporate. A heat gun on low heat will help speed up the drying process.

I try to avoid epoxies and glues. Most dry out over a long period of time and become brittle. They break from expansion and contraction, damaging the coil. This is what killed many of the original EMG pickups. This is why the earliest ones are scarce, most died in the 90's.

But some epoxies are just fine. I recently recovered some epoxy potted pickups I made in 1964 or 65 when I was in high school and they are OK.

[Jim Shine]

Yes, some is the key word. Whatever EMG changed to seems to last with the earliest of that material appearing a little over 20 years ago. The trick is finding the epoxies that stay flexible. Some just hear "epoxy" and go grab whatever they can lay their hands on. Not all epoxies are equal. Unless I knew beyond a shadow of a doubt what was safe, I am not up for experimenting on stuff that wont be with me long.

[David Schwab]

I try to avoid epoxies and glues. Most dry out over a long period of time and become brittle. They break from expansion and contraction, damaging the coil. This is what killed many of the original EMG pickups. This is why the earliest ones are scarce, most died in the 90's.

I encapsulate all my pickups, and you have to use epoxy made for potting. The stuff I use has nylon filler it in. It does not shrink when cured. It doesn't have to be flexible at all, it just can't shrink.

I have several very old encapsulated pickups that are fine. I have a Hi-A pickup I bought in 1976, and an old Overlend EMG mini humbucker. Both work just fine. The EMG has the tan colored epoxy in it. I also have some of the pre connector EMGs from the mid 80s, and some original Bill Lawrence pickups frm the 70s which were encapsulated with polyester resin. The only encapsulated pickup I have ever seen fail was an obscure Bill Lawrence pickup that looked like an EMG humbucker. This was made in the mid 80s. One coil had gone bad in the pickup where it connected to the hookup wires from the solder clips. This was also potted with clear polyester resin.

I think you just don't see many old EMGs because they are still in service. Their original SA pickups sounded better because they had more wire wound on them, but they had a hard time fitting them in the covers, and the tan epoxy bulged out the back. That was one of the reasons some of the pickups had problems.

Here's some real relics!

[Possum]

Your potting wax will work at only 150 degrees farenheit, thats not really hot, you can dip your fingers in and not get burning. Shellac isn't always a good idea, the alcohol has water in it and water will knock off some treble response. I lacquer pot my P13's because thats how they were potted and have yet had one die, using plain enamel wire, poly wire I'm not so sure about, you could contact the wire manufacturer and ask about lacquer thinner. You might just want to try taping the coil real tight, Guitar Jones (do they still exist?) had a scotch type black tape that will stretch and allow you to tape a coil really tight. Most squeal comes from the outer layers, but P90's can squeal from the core if you wound pretty loose.

[Ronsonic]

Has anyone tried running a vacuum on their potting or encapsulating rig?

It's done industrially, especially for polyurethane potting materials. Kinda gotta watch the volatiles with shellac and lacquer and the cloggers like paraffin. Haven't done it myself, but ....

Also a shaker or vibrator in the pot (no jokes guys) could improve things.

[Ronsonic]

I just made a P90 bobbin out of Maple and wound it with 8,000 turns of 43 AWG. I'm a bit concerned about dipping it into hot wax out of fear the bobbin might warp. Has anyone tried to apply CA glue to a coil as a way to dampen microphonics? I'm hoping it will soak in and dry super fast.

Once upon a time it was common for mil and industrial coils to use a felt saturated with shellac as the last guide on the coil winder so the coil would glue itself together as it was wound. There was also wire with a precoat that could be softened with just an alcohol wetting as it was wound. Of course you're past that point now.

[marku52]

Seymour Duncan vacuum pots using wax, I saw it on a youtube clip of his manufacturing process. Probably others do as well.

[captcoolaid]

I have been using shellac for my middle and neck single coils for a few months now. Works like a champ. I know mouse who I got the idea from has been doing it for years with his.

[copperheadroads]

I have got yet to figure out whats wrong with wax potting
What is the advantages of using shellac