If you haven't read the last instalment:
...so, the problem I was left with was that I hadn't grounded the strings and both my tailpiece and bridge are made of wood (and bone, neither great conductors!)
I decided to go for a pretty drastic solution. Here is the problem:
This is part of a hanging fixture ( one of the advantages of working in a department store, few though they are), I used a Dremel to cut it to the right size and drilled a few holes to mount it to the back of the guitar and 3 to hold the string ferrules. I have used bike spoke nipples for these. At 20p each at my local bike shop they're a lot cheaper than real string ferrules!
The idea was to solder a wire to the inside of the tailpiece and connect it to the ground on the back of the volume pot. What I hadn't considered is that it's bloody difficult to solder to stainless steel. I didn't have any flux to hand so I cheekily superglued a strip of copper foil tape to the tailpiece and soldered the wire to that... hopefully this will work!
So here's the new tailpiece. I actually never liked the original so wasn't too sad to see it go. The sound still seems to be just as nice so I'll take that as a success...
I soldered the wire onto the back of the pot and checked all the connections. I plugged it in and the loud continuous buzzing had all but gone! I now had a slight buzzing which went away when I touched the strings... after sending myself mad Googling this for a couple of hours I found a lot of conflicting advice, mainly:
Now I'm perfectly ready to accept that I'm not very good at soldering, as I have no previous experience with it. However I figure that if everything works, the soldering should be fine, right?
I eventually decided to believe number 2. I noticed that there was very little hum when I left the guitar in the middle of the room, and stood away from it. I also noticed that not having my amp plugged into a socket with a PC, Laptop and a baby monitor made a big difference. If anyone reading this has any other ideas I'd love to hear them!
So, I still had one last trick up my sleeve - my copper foil tape. I thought I'd give it a try on one of the new pickups I made following (I thought) Bob Harrison's suggestion.
So I have potted the coil, wrapped it in a few layers of plumbers' tape, and then wrapped in a layer of copper foil. I then ran a jumper lead from the ground connection (start of the coil) and connected it to the foil. I also used a little lump of solder to seal the foil shut in case the glue deteriorates over time.
Somewhat foolishly, I whacked the pickup in the guitar without checking it first... when I plugged it in, it didn't work. No signal, some buzz, but definitely no sound coming from the strings. Without really bothering to figure out why, I took it out and removed the copper foil (trying to grasp electronics by this point was making my head hurt). After ruminating on this over the last couple of days, I think that maybe I shouldn't have connected the ground wire to the foil and the start of the coil. If the ground is the path of least resistance, maybe I have just forced the current directly to ground... again, any feedback on this would be appreciated!
Sure enough, after removing the foil and the jumper lead, the pickup worked again. I strung it up, closed the access panels and called it a day. Some noise, perhaps, but hardly too offputting for a first attempt!
...and here's a video - let me know what you think!