Bass Pickup Shell

[David Schwab]

There are a couple of different black pigments often used for polyurethane casting resins like Alumilite. Get the carbon/lamp black. The other is iron oxide, and boy, will you be surprised when you cast a pickup with iron oxide pigmented resin! At least you'll be able to see the shape of the magnetic field(s)...though who knows what the effect might be on sound.

Oh my... that can't be good! I'll report back when I get the stuff this week.

BTW, the earliest Bartolini shells were vacu-formed, not injection nor open cast molded. That's when they were called "Hi-A" pickups.

I was wondering how he did the covers on the old Hi-As. I have an old one I got back in '76.

[RedHouse]

There are a couple of different black pigments often used for polyurethane casting resins like Alumilite. Get the carbon/lamp black. The other is iron oxide, and boy, will you be surprised when you cast a pickup with iron oxide pigmented resin! At least you'll be able to see the shape of the magnetic field(s)...though who knows what the effect might be on sound.

BTW, the earliest Bartolini shells were vacu-formed, not injection nor open cast molded. That's when they were called "Hi-A" pickups.

Hiya, Bruce...

Are you the same Rick Turner as this?:

Turner Renaissance Model T guitar

[David Schwab]

Brad, that is indeed the Rick Turner.

[RedHouse]

Brad, that is indeed the Rick Turner.

Oh how cool.

So let me ask the 64k question Rick (since everyone here wants to know), how do you manage to get around the wrath-o-John Hall regarding your horseshoe pickup? he (JH) has publicly stated he feels it's a Rickenbacker trademark infringement to make them for sale. Do you buy them from Rickenbacker to install on your Renaissance Model T guitars?



seems others who have tried to make them are getting litigation threats in a C&D letter.

(this issue has come up several times on this forum)

[Rick Turner]

For one thing, I just make them a very few at a time, and I've been making them in continuous production for about 20 years now, pre-dating any trademark application that I know of. I got "Editors' Pick" a number of years ago in Guitar Player Magazine and heard not a word about the whole thing other than how great the pickups sound.

As I understand it, the claim is that the horseshoes are a visual element. I maintain that they are a crucial element in the magnetic circuit, and so are not covered by trade mark, and as the original patent is well past expiration, the horseshoes, which in my pickup are actually working pole pieces, are a non-protected functional utility feature of the pickups. As you probably know, some of the modern pickups that look like horseshoes are nothing more than plated plastic...the horseshoes are totally visual. Mine are big old chunks of iron, and while they are not the original cobalt steel magnets, they have a similar effect in bathing the strings in the magnetic field. I'm using 1/4" Alnico 5 magnets in a big coil wound with 7,500 turns of 40 gauge wire now for relatively low DCR. Just wound a couple with Teflon insulated wire. I'll report in when I fire them up. One of the interesting things about the huge horseshoes is that they also provide a fair amount of magnetic shielding, so these single coils have much lower hum than you'd expect. They're also pretty efficient as flux variations are brought down to the bottom of the coil better than on more conventional pickups. One thing about the pickup makers of the early '30s is that they had to make efficient pickups and get as much voltage per turn as they could. There's only two ways to do that that I know of: 1) Pancake coils, or 2) Efficient pole piece design That's probably why Leo's later pickups featured some relatively shallow coils and also some with polepieces. I think he was trying to get more output without adding much wire.

[RedHouse]

For one thing, I just make them a very few at a time, and I've been making them in continuous production for about 20 years now, pre-dating any trademark application that I know of. I got "Editors' Pick" a number of years ago in Guitar Player Magazine and heard not a word about the whole thing other than how great the pickups sound.

As I understand it, the claim is that the horseshoes are a visual element. I maintain that they are a crucial element in the magnetic circuit, and so are not covered by trade mark, and as the original patent is well past expiration, the horseshoes, which in my pickup are actually working pole pieces, are a non-protected functional utility feature of the pickups. As you probably know, some of the modern pickups that look like horseshoes are nothing more than plated plastic...the horseshoes are totally visual. Mine are big old chunks of iron, and while they are not the original cobalt steel magnets, they have a similar effect in bathing the strings in the magnetic field. I'm using 1/4" Alnico 5 magnets in a big coil wound with 7,500 turns of 40 gauge wire now for relatively low DCR. Just wound a couple with Teflon insulated wire. I'll report in when I fire them up. One of the interesting things about the huge horseshoes is that they also provide a fair amount of magnetic shielding, so these single coils have much lower hum than you'd expect. They're also pretty efficient as flux variations are brought down to the bottom of the coil better than on more conventional pickups. One thing about the pickup makers of the early '30s is that they had to make efficient pickups and get as much voltage per turn as they could. There's only two ways to do that that I know of: 1) Pancake coils, or 2) Efficient pole piece design That's probably why Leo's later pickups featured some relatively shallow coils and also some with polepieces. I think he was trying to get more output without adding much wire.

Thanks for responding Rick, very cool indeed.

So if I make my people horseshoe pickups, noting they're "Rick" style, perhaps I can dodge the wrath-o-John C&D letter by implying it's based on the "Rick" Turner horseshoe rather than the Rickenbacker pickup. Might be an angle there, I don't get a lot of inquiries, but I have had maybe half a dozen over the past year and it's a shame to turn people away just because of JH's sabre rattling.

[David Schwab]

Brad, Rick has been making them before Rickenbacker got a trademark on the look of the horseshoe. And we all know they don't make a real one. Lord knows we discussed this to death her! So since her predates a trademark, they probably can't do anything.

And Rick, we always wondered how you didn't get harassed by them, like that other guy that made horseshoes, so now we know.

[David Schwab]

Oh yeah, Rick you will love this one! Especially since you had the patent on the first graphite neck.

I posted somewhere on the music electronics forum, that Rickenbacker needs to put some graphite rods in their bass necks, and then they can get them nice and thin like they used to be. I have two '74 4001s, and never liked the 4003's neck.

So lo and behold, I get an email from JH. He said he read my comment and went on about how they can't do that because there is a patent on graphite neck reinforcement, and then he cites me the patent number for Moses' "construction of a graphite neck" patent. This of course has nothing to do with graphite neck reinforcement!

I wrote him back and pointed that out, along with the fact that Moses Graphite will gladly sell you graphite neck reinforcement rods. I also pointed out all the luthiers and even big companies like Fender, that use it. Then of course Modulus and Steinberger. He said his legal council knows best, and all those other builders are small fish compared to RIC!

And besides, he had a "better idea" soon to come. Like the new bridge, and wider pickups and new truss rods...

I like the design of a lot of their stuff.. the Rossmeisl designs, but they need updating.

[RedHouse]

...So since her predates a trademark, they probably can't do anything...

I don't feel it was discussed to death, anyway it was my point that it would definately have an effect on the trademark arguement of JH.

I'm not trying to make trouble, just haven't liked the heavy handed dealings against the smaller (than Rickenbacker) pickup makers that has gone on. One wants to make and sell a Horseshoe or Toaster pickup but has to litterally fold from just the possibility of a lawsuit knowing JH can afford to out-spend one on attourney's fees. (sigh)

[Rick Turner]

I am not looking to piss on anyone's parade. I'm not looking for patent or trademark disputes. I do my thing; I give credit where it is due as far as I know; I blaze my own path, and if I find predecessors, I acknowledge, give way, and/or keep moving along the path they have shown exists.

The Barth/Beauchamps horseshoe pickup was the first commercially successful magnetic pickup design. As much as I believe that Lloyd Loar was probably the true inventor of the electric guitar, I credit what became the RoPatIn design as being what it is...amazing to this day and the first truly important string sensitive magnetic guitar pickup. But it's shape; it's basic aesthetic is NOT driven by some Hollywood set designer; it is extremely functional. It's not a look...no matter how unique it is. It represents a sound, and that is a matter of utility, not trade mark visual look.

[David Schwab]

I just ordered some of this to try out:

AeroMarine Products - Casting Resin

I already use his epoxy.

So I got this casting urethane. I'm in the process of casting a few pickups in rubber molds. My initial observations are that it cures really quickly, and it also gets very warm, which caused me some concern since I'm using neo magnets. it's nice and black too.

Ok the timer went off so it's time to demold...

[Marko Ursin]

Heating is the reason why I'm trying to cast only a cover for my 2nd versions of the eight-coils. I made a couple four-coil pickups and for some reason the covers distorted on top of the coils. Maybe it was the heat, maybe not. Anyway I'm trying to make covers and hot glue them to the pickups.
Marko

[David Schwab]

Normally I use slow setting epoxy, and it doesn't get warm, but it takes 24 hours. This stuff gets quite hot if you have too much in a cup.

What I have been doing with the molds is to pour enough to get a clean front face cast, and then after that cures, I put the pickup in and fill the mold up.

One problem I have encountered is the second pour getting past the edge of the first and ruining the front finish. I much prefer working with premade covers. Also this urethane seems to need a release agent. My first try came out perfect, and the second's finish isn't as good, even though the mold was clean.

Maybe the front of the cover you did was too thin and the weight of the coils distorted the mold?

[doc-bass]

David... Do urethane casting need to defoaming machine.?

[David Schwab]

I didn't have any foaming problems.