I just got done putting a relic treatment on a set of Sta-tite tuning machines from Grover, to match my tailpiece and bridge. It's a pretty easy procedure though a bit time consuming, and it takes a few specialty items which you can find at radio shack and your cupboard or grocery store. Here's a list:
1 Wired Battery Holder for 2 AA's
2 AA Battery's
2 crimp style alligator clips, large enough to clamp onto at least a 1/4" piece of metal
some shielded wire to match the gauge of the wire on the battery holder
2 wire nuts
a resealable container, I use a cheap Glad leftover container
white vinegar
a 1 1/4" x 3" strip of copper. I cut a 1 1/4" section of 1" copper tubing on the chopsaw, then cut through it lengthwise and flatten it out
1 US quarter
some 320 grit sandpaper
a paper plate
Start out by attaching the loose wire to the alligator clips, I used the crimp on kind because they will corrode through the process and I didn't see the use in soldering something that I'm just going to cut off later. Attach the other end opposite the clips to the wires coming out of the battery holder using wire nuts. Now that you have the electrical component ready you will want to make a copper solution.
I did this by taking the copper strip and placing it in the clip that's connected to the negative lead of the batteries. In the positive clip I placed a quarter to give more surface area in the solution. Place both clips in the tupperware filled with about 2 cups of white vinegar. You should start to see fine bubbles forming on the surface of the copper, and the solution should take on a copper color. Leave this to boil for at least twenty minutes.
I should mention that I do this just sitting at my dining room table, and don't notice any noxious fumes and there isn't any risk of electric shock. You can actually hold the clips in the solution and won't feel a thing so it doesn't seem to be dangerous or anything. The acid in the vinegar isn't strong enough to burn you either, but measures should be taken to keep things contained and clean so I like to put a towel down under where I'll be doing this.
After you've got your solution ready it's time to flip the connection on your clips. I take the lead coming off the positive and connect it, after disconnecting from the negative mind you, to the copper strip. You can just leave the copper in the solution with the negative lead sitting out of the container and it won't cause a problem, as it's just an incomplete circuit. You should have something that looks like this:
The next step is to scuff your hardware so it'll accept the patina effect of the copper solution. This is pretty easy with something like a tailpiece as it's just a matter of sanding and putting it into the plating solution for about half a minute. In the case of my tuning machines, I deemed it best to disassemble these before I sanded and plated. I should mention at this point that I'm not sure what effect this process would have on a sealed tuning machine. I chose the Sta-Tite's because they have an exposed mechanism and I could make sure the parts were thoroughly dry and clean before I reassembled.
Taking these apart is fairly straightforward, you basically take out the screw at the pinion gear connected to the string post, and another which holds the thumb screw to the tuner carriage. I like to use a paper plate to contain all of the parts while you're working with them because some of them are darn small and easy to lose. Once you've done this, take the 320 grit sandpaper and scuff the surface of all the parts which will be exposed after final assembly. It's important to take all of the shine off of the surface, because what's still shiny will not take the plating solution and will just end up looking the same after you're done, which will ruin the effect. Here's an example of what it should look like:
I should also mention at this point that you can sand until copper layers are exposed under the chrome/nickle surface that came from the factory. I kind of like this and think it adds to the effect but if you don't want to do this you could move up to 400 grit and be a little less aggressive sanding. You still need to completely take the shine off though as I said above.
I like to do one machine at a time just because I think it's easier to keep track of all the pieces that way, and because I found it helpful to have another assembled machine to compare how everything fit together when I reassembled these. Take the parts, one at a time and connect them to the negative lead. Place them in the solution for at least 20 seconds, keeping in mind that the longer you submerge the piece the darker it will get. You should be seeing bubbles forming all over your part which will tell you it's working.
Keep in mind that a fair amount of the color that you've gotten on your parts is going to just wipe off, so I tend to leave the parts in until they are fairly dark and what looks like black, pitting appears on the surface probably after about 40 seconds. I've also found that if you really want it dark, you can take another step which will make a big difference. Basically you want to reverse places between the copper strip and your part so that your part is connected first to the positive pole and the copper to the negative. This seems to chemically etch the surface of the part and allow it to take on even more dark color. After this step switch the leads and continue as instructed above.
After you've finished all of your pieces, wipe everything down with a paper towel and make sure everything is good and dry. Reassemble your machines and there you have it, relic'd tuning machines.
Here's what they look like compared to standard:
and finally the whole set:
Like I said it's pretty straightforward, but it is a bit time consuming. I do like the fact that I can do all of my pieces at the same time and don't have to worry that one company's relic'ing won't match another's since you'll be getting different parts from different sources, plus you'll likely save a few bucks over buying them with the finish done.
So there you go the super, non-scientific, kitchen table plating technique I used to relic my parts. I'm very pleased with the results and can't stand the look of super shiny metal so I expect I'm going to get very familiar with doing this.
