Good ways of attaching shielding

[Joe Gwinn]

I hear what you're saying Joe, but even at that I still ended up eliminating a lot. A lot of my trolling/irritating questions on this board were about trying to figure that stuff out. I'm using a laminated blade, so I wanted to remove all the shielding from around the blade (or at least on three sides), then I had a cut to take care of the eddy current looping, and then I have a series of eyelets and such, all of which needed to be carved away. I also trimmed it in other areas. By the time I did all of this I just decided that I was going to be just fine sacrificing the shielding. Plus, not using the copper clad opens up other possibilities for production, and it lets them be reversible for lefty sets. This design has become kinda complicated, and I want to make it simpler wherever I can so they can be produced for a reasonable price. I see the wisdom/convenience of using copper clad and carving it, but I tried it and really didn't think it was worth while. I'd reconsider it for other form factors, but for this one it just wasn't making sense. The only downside is I'm left figuring out how to do my grounding, but I'm confident I'll EVENTUALLY come up with something.

I can't say that I follow this. But I fear that you are working too hard.

Could you provide a drawing or sketch?

And just for my own curiosity, would the 1/16" gap COMPLETELY eliminate capacitances, at least perceptible ones? I feel like I already know the answer to it, but since we're on the topic I thought I'd ask.

Well, you cannot eliminate capacitance, but you can make it a trivial problem, and a 1/16" gap makes a pretty good start on that.

[FunkyKikuchiyo]

"But I fear that you are working too hard."

I'll take that as a compliment. Not sure if the way you mean it is that I'm over thinking it, but I take what I can get. I've been working for over two years on this exact pickup design and am REALLY anxious to have something to show for my work. Once I have more designs under my belt I probably won't be so neurotic and wound up (no pun intended) about it, but this one is definitely a "keeps me up at night" sort of thing.

I have CAD drawings, but I don't think they'll readily explain what I'm doing. Imagine typical Strat bottom flatwork. Make it G10 and for use with a blade. I'm still using press in eyelets even though I could've just used the copper clad because I preferred the slight advantage structurally - that is the repair guy in me thinking, I suppose. So, each of those had to be cleared out. Copper all the way around a laminated blade would almost entirely defeat the purpose of having a laminated blade if my understanding is correct, and it can only be shorted out in one place for the ground. All of this just meant a lot of clearing out of copper, and since I'm sending work out to be cut, I wanted to keep it simple to save money. Not every commercial CNC company wants to deal with copper clear outs, either. If I had my own CNC I may have stuck with copper clad, but I opted to ditch it since the only function it really had in the end was to give me a place to solder my ground wire. I felt like any noise reduction was negligible.

David - yeah, I'm trying hard to clean up the high end. I'm listening closely to the extended highs and trying to keep those as pure as possible. Having plenty of upper mids can give you a functionally bright tone, but it isn't quite what I'm after. Every time I pull something off of the pickup to make it more efficient like that, the richer the timbre sounds to me. Really it just comes down to where I'm trying to go with this design and my own tastes. I'm trying to get a blade design to have that simple, pure sound of a typical strat pickup.

Plus, if I was still using solid blades, I'd probably have stuck with the copper clad. But, at this point I just would rather not deal with it any more.

[Joe Gwinn]

Copper all the way around a laminated blade would almost entirely defeat the purpose of having a laminated blade if my understanding is correct, and it can only be shorted out in one place for the ground. All of this just meant a lot of clearing out of copper, and since I'm sending work out to be cut, I wanted to keep it simple to save money. Not every commercial CNC company wants to deal with copper clear outs, either.

Well placed radial cuts will break up the eddy currents, even if most of the copper remains in place. The cuts are best made by etching. There is no harm in keeping the eyelets, if the copper is properly cut.

If you provide a drawing showing the copper area and the blades, I will be able to say more definite things.

What bothers me is that what you are trying to do ought to be easy, and so I don't understand why it's hard.

[David Schwab]

David - yeah, I'm trying hard to clean up the high end. I'm listening closely to the extended highs and trying to keep those as pure as possible. Having plenty of upper mids can give you a functionally bright tone, but it isn't quite what I'm after. Every time I pull something off of the pickup to make it more efficient like that, the richer the timbre sounds to me. Really it just comes down to where I'm trying to go with this design and my own tastes. I'm trying to get a blade design to have that simple, pure sound of a typical strat pickup.

Plus, if I was still using solid blades, I'd probably have stuck with the copper clad. But, at this point I just would rather not deal with it any more.

As long as it's a dual blade humbucker, your highs will be limited somewhat. I went through a lot of the things you are doing, such as laminated blades. I actually used laminated stainless steel blades.

I did have a Bill Lawrence pickups once; it looked like an EMG with the closed cover, and it had the glassiest highs ever. It used solid blades. I know because one coil went dead, so I dissected the pickup.

[FunkyKikuchiyo]

I had cut out for all of those things. No, it isn't all that hard, but in the prototype stage I had a CNC setup where I could go over at a different depth and do all that stuff again for the cut outs. I had the radial cut that you mentioned, cut around the blade, and cut around all of the eyelets (I have more than usual because of how my series connections were laid out). Doing a few of them it is no big deal, but if I'm trying to do a batch, it all adds up. I'm trying to control costs, and ultimately I decided that the final benefit of doing it this way (a quick way to attach grounds, and shielding on the bottom part of the coil) just weren't worth the effort/expense. As I looked around for people who could cut flatwork for me, not everyone wants to do the partial depth necessary, so keeping the shielding would mean being even more selective about CNC cutters than I already have to be, and making it more expensive than it already is. Do it a few times and no big deal - do it 150 times, and it adds up.

If I can come up with a decent way of grounding the blades without dealing with the copper clad, then I've essentially reached the same end for a fraction of the money.

David - we've probably had some very different experiences, but I've found the laminated blade to be critical to the sound I'm after. There are many, many ways to laminate and they each behave a bit differently. I'm not saying there is anything wrong with solid blades, I just know that for this design the laminated kind is what I need to use.

Well placed radial cuts will break up the eddy currents, even if most of the copper remains in place. The cuts are best made by etching. There is no harm in keeping the eyelets, if the copper is properly cut.

If you provide a drawing showing the copper area and the blades, I will be able to say more definite things.

What bothers me is that what you are trying to do ought to be easy, and so I don't understand why it's hard.

[David Schwab]

David - we've probably had some very different experiences, but I've found the laminated blade to be critical to the sound I'm after. There are many, many ways to laminate and they each behave a bit differently. I'm not saying there is anything wrong with solid blades, I just know that for this design the laminated kind is what I need to use.

In my case I found the tone of the stainless steel blades to be too harsh, but it was likely in conjunction with everything else in the design. Solid blades warmed up the tone.

You should have your copper clad board etched by a company that does circuit boards, and then just cut it to the shape you want. You can also use that to attach your coil wires like Duncan and DiMarzio do. Or photo etch it at home.

[FunkyKikuchiyo]

David - that sounds reasonable. I haven't worked with stainless blades, but I have worked with higher carbon steels, (I actually made a pickup out of Stanley razor blades once - a literal blade pickup!) and I can imagine that a laminated stainless blade is probably pretty extreme.

My whole point is that I only needed the bit of copper to make my grounds neat and pretty, and it doesn't warrant all those processes. If I build my own CNC setup (Christmas hint for anyone who is reading) I may revisit it, but right now it falls in the "not worth it" pile.

I suppose the general conclusion is that there is no way to attach copper to G10 that'll be nearly as strong as having copper clad to begin with. It makes me wonder how they make the copper clad to begin with, but it is immaterial. I'll seek other methods of making a ground. I think I can fashion something out of scraps of copper or brass more easily than the etching, so when I have a chance I'll experiment with that.

[Joe Gwinn]

I had cut out for all of those things. No, it isn't all that hard, but in the prototype stage I had a CNC setup where I could go over at a different depth and do all that stuff again for the cut outs. I had the radial cut that you mentioned, cut around the blade, and cut around all of the eyelets (I have more than usual because of how my series connections were laid out). Doing a few of them it is no big deal, but if I'm trying to do a batch, it all adds up.

CNC is certainly good for prototyping, but for production I would have circuit boards made commercially. There must be a dozen companies that do this, in all quantities, starting with one or two. They will also drill the holes and route the slots, using equipment we can only dream of.

Here is a source of possible sources: EETimes. Download a copy of the current issue (look for "Lightning in a bottle", on the right edge about 1/3 of the way down). Look on page 53.

I'm trying to control costs, and ultimately I decided that the final benefit of doing it this way (a quick way to attach grounds, and shielding on the bottom part of the coil) just weren't worth the effort/expense. As I looked around for people who could cut flatwork for me, not everyone wants to do the partial depth necessary, so keeping the shielding would mean being even more selective about CNC cutters than I already have to be, and making it more expensive than it already is. Do it a few times and no big deal - do it 150 times, and it adds up.

If I can come up with a decent way of grounding the blades without dealing with the copper clad, then I've essentially reached the same end for a fraction of the money.

It strikes me that there is an alternative, brass shimstock. If one puts a piece or 0.001" to 0.003" thick shimstock in the slot before pressing the blade in, the shimstock will make firm connection to the blade, and one can easily solder to brass, or pinch an eyelet down on the shimstock. One can cut such shimstock with ordinary scissors (intended for paper), and form it with the fingers.

Shimstock is cheap: MSC Item Detail. This is the 0.002" stuff; other thicknesses, widths, and lengths are available.

[FunkyKikuchiyo]

Thanks, Joe... I've actually already ordered G10 cut to my drawings without copper clad so those aren't options any more, but I appreciate the effort.

I like the idea of brass shim stock. Crazy easy to solder to, I can epoxy it to almost anything I want, and it is cheap. I'm not sure if I have any currently, but I used to keep a perpetual supply for shimming floyd parts and such.

[kurtdaniel]

My current build is shielded with, I think, aluminum duct tape. At least that's what I used to cover the spots that looked as if they'd been mishandled. As of now, the luthier setting it up who has good guitar how to knowledge hasn't found any problems..

[David Schwab]

Thanks, Joe... I've actually already ordered G10 cut to my drawings without copper clad so those aren't options any more, but I appreciate the effort.

I like the idea of brass shim stock. Crazy easy to solder to, I can epoxy it to almost anything I want, and it is cheap. I'm not sure if I have any currently, but I used to keep a perpetual supply for shimming floyd parts and such.

I mentioned earlier, but maybe you missed it. I use 40 gauge copper for shielding. You can also get brass and aluminum. I buy it in an art supply store. You can get different gauges too.

It wouldn't be hard at all to affix to the PCB with spray mount or contact cement. Or epoxy if you want to be even more sturdy.

Or get a can of SuperShield paint.

[FunkyKikuchiyo]

I did see it, I'm just contemplating a few different ideas. I'm at a bottleneck with parts supplies right now (not related to the shielding) and once I have everything in front of me, I'll probably experiment a bit.

[RedHouse]

Adding copper is do'able, search on MG chermicals website I'm sure I saw a video on there showing their stuff for adding copper to G and FR board, they do it all the time making plated through holes and via's on PCBs.

The thing would be to create a screen (ie silk screen, which aren't silk but never mind) with your pattern and go from there.