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Superglue & shellac potting?

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5/5/2006 11:39 AM

Superglue & shellac potting?

This is kind of interesting. I was reading the MIMF archive, when I came across a post discussing Rick Turner's horseshoe pickups.

Rick had this to say:

[QUOTE]I'm patterning mine on what I think is the third or fourth version used on the "Frying Pans" and on the "Bakelite" lap steel pickups. I'm also using a black teflon coated base plate, laser cut flatwork, precision wound coils vacuum potted with shellac, and oxygen free Mogami lead out wire.
...

The shellac potting is new for us. I used to use superglue, but, damn, the shellac makes for a great sounding coil! It's tough enough to eliminate loose turns, but soft enough to not make the coil ring. [/QUOTE]

Superglue? Yikes! Brings back memories of the time my ex-partner glued his finger to a guitar while attaching the binding! I was feeding the glue and he was pressing it in the slot... oops! Took forever to unglue him!

Anyone try shellac?

5/5/2006 11:58 AM
Roscoe	I tried shellac long time ago, see my post below on potting, I didn't like what it did to the sound. Looking back on it it could have had something to do with the alcohol still in the shellac creating a wet coil. I dryed the other coils with a warm lamp after that. Just don't see much of a benifit except tape sticks better than on wax.

5/5/2006 12:16 PM
rf	To expand, Turner also said (in another discussion) that he felt shellac was "just right" for potting -- not as hard as superglue, not as soft as wax. He pots using a vacuum, then puts the pickups in the oven (on pilot light only) overnight to cure. After that he pots in epoxy -- I believe it's just enough to cover the outside of the coil.

5/5/2006 9:31 PM
Ken	I tried superglue, I didn't like it because of the fumes and my pickups didn't seem to look quite right. I only use it for demo pickups I use at shows so the coil wires won't break. I'm curious about shellac, I'm going to try it. Did you notice what he's copying with laser cut flatwork and oxygen free wire? A 1930's pickup. Interesting. Ken

5/7/2006 5:01 AM

Shellac only works for 42 gauge wire, I used to use but quit. The problem with shellac is that it dries from the outside in, basically it seals the outside of the coil while the inside of the coil can remain wet for weeks. A wet coil drastically increases the inductance and makes your pickup sound like someone screaming underwater. You can get away with it with 42 gauge but you'll have to really let your coils dry for a week. with lighter gauges I had some that never dried out even cooking them in a toaster oven. Opened one after baking for a couple hours and just sticky and gooey inside, it eventually dried out after a couple months..........

5/7/2006 8:00 AM

quote:
"I had some that never dried out even cooking them in a toaster oven. Opened one after baking for a couple hours and just sticky and gooey inside, it eventually dried out after a couple months.........."

That doesn't sound good at all! Yuck! Turner says he puts his in an oven with just the pilot light on over night to let them cure, but I can't see how they would cure on the inside with no air circulation.

OK forget that idea!

5/7/2006 6:09 PM
Dave Stephens	like I said it works with 42 gauge wire fairly well, but 43, 44, the wire is thinner and because of that the stuff won't dry out, it gets trapped inside, 42 you can get away with it, I just plain don't use it as I use an LCR meter and you can plainly see on that thing when the stuff hasn't dried....

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