Electrolytic metal etching of Humbucker pickup covers?

[Velcelt]

I have an arch-top kit guitar I'm putting together and I had gotten this idea to do all sorts of embellishments of the knock-off Bigsby vibrato, the pickup covers, etc. My idea is to use electrolytic metal etching. If you're familiar with the process, (easiest, least toxic method). basically you make a concentrated salt water solution then take a battery charger and set it for 12v 2 amp output. You create a design and mask off what do or don't want to be etched with paint or something like a vinyl mask printed on a vinyl cutter. I've experimented around with this in the past and you take the negative cable and attach it to one part of what you want to etch,, then you take a piece of rag or cheescloth and dip that into your dissolved salt solution. That little wad of cloth then gets clipped into the positive clamp and you then touch the positive clamp with cloth to the exposed areas of metal that you want to etch. The reaction essentially rapidly corrodes/removes the upper layer of metal creating the etch. Keep doing it until you remove enough metal to get the level of depth of etch that you want. Now, my reason for asking this question here, especially in the Tech forum is that I figured asking where people are talking about electronics and pickups would be the best location. My main concern is on a pickup where the covers are already attached/soldered to the pickup, would this eletrolytic etching process in some way mess up the magnetism or other electrical properties of the pickup? I guess the best way to be sure you wouldn't ruin something with the pickup would be to desolder the joints holding the pickup cover to the underside of the pickup itself. I'd rather not have to do that if it isn't necessary, hence asking if anyone thinks this process would be electrically harmful to the pickups in some way. For the record, they're Gotoh HB Classic Alpha pickups with Chrome covers. 

[curtisa]

I'd be more concerned about dunking them in a saline solution for a couple of hours and allowing all that electrolysis mess to get anywhere near the windings. I reckon you're better off removing the covers and performing the etching process just on those parts.

[Velcelt]

One way of doing electrolytic etching is to completely submerge a part, but that's not really necessary. A decent etch can be achieved just by applying the solution with the anode (or is it cathode - can never remember which is which), directly to the area being etched. With proper taping I'm pretty sure I could prevent getting any saline solution into/under the pickup cover and onto the windings. I'm just more concerned about whether hooking up the current can somehow mess up the electrical field of the pickup. I do have some cheap, crappy Humbuckers that I could experiment with. I guess the thing to do would be etch the cover then just hook test leads up to the pickup and see if the coils still respond when touched with a something like a screwdriver. 

[curtisa]

I couldn't say one way or the other whether the electrolysis process would have any impact on the magnetism of the pickup components. A magnet may be de-magnetised by applying an alternating current through it, but your 12V battery charger and electrolysis process is DC. If you can guarantee that the magnet is electrically isolated from the pickup (or at least arrange the two electrodes such that the current gets no opportunity to pass through the magnet) before it gets dunked maybe you'd eliminate the possibility that the electrolysis process could strengthen or reverse the polarity of the magnetic field in the pole pieces? Dunno...

With a moderately powerful soldering iron I personally don't consider de-soldering the case from the base such an onerous task compared to any unknown risk of ruining a set of pickups by dropping the whole thing in, but that's just me.

[Velcelt]

I watched a couple videos and it looks like removing/installing a Humbucker cover is pretty simple so I'll just do that and remove any issue with potentially messing with the actual electronic guts of the pickup. 

[Drak]

Yes, by all means do not try to dunk the entire pickup, I see complete dead-fail in all caps with that.

Removing the cover, two typical methods:

Dremel tool with a cutter wheel (total PITA if you ask me, I've tried it and didn't care for it, tho it does work)

And heating it up with a soldering iron, which is what I prefer to do.

But, you need a reasonably powerful soldering iron and set it all the way to maximum caliente (hot).

There's so much metal there, it all acts as a heat absorber and sucks the heat from your iron away from the joint.

So its gotta be REALLY hot and you have to be ready to act pretty quickly.

As once you get it hot enough, the second you pull the iron away to start prying the cover from the base, it will begin to cool immediately.

Truth, having another pair of steady hands around would be super helpful.

You can have someone else holding the iron steady on the joint while you suck the solder out or pry the two apart.

However you do it, another pair of STEADY hands is very handy here.

[mistermikev]

idk guys... maybe you SHOULD dunk the whole pickup... then you can call it an antiquity!  

have often thought about etching pickup covers.  I've never done the electrolytic method but have etched about a zillion pcb boards and lots and lots of aluminum pedal enclosures with both Ammonium persulfate and ferric chloride.  Idk if electrolytic generates any heat but ferric sure does and that would def melt the wax potting on a pickup.  

sounds like you are on to taking the cover off anyway... good on ya.  would love to see pics of the process.  

what I know about pnp blue/ferric/persulfate etc is that it take a lot of trial and error to get a fine detail design to come out using etchant.  always end up with micro bubbles in the overlay and have to spend a lot of time patching with an etch pen.  even if you get the thing perfect... if it gets heated pieces can flake off and create ugly spots.  PITA but it can be done.

with all that in mind... if I ever get there - def going to get a laser for etching that sort of thing!!