Hello, everyone!

I just recently purchased a (new) Fender Standard MiA Strat last week. What I noticed with this guitar, as expected, is that it has some of that "good 'ole" 60hz hum.

What I did was pop open the pickguard to inspect everything underneath. What I found was that there was this black paint substance in the control cavity along with a wire that was screw into the cavity on one end and soldered onto the back of the volume pot on the other end. The back of the pickguard came with aluminum foil all over the back plus ground wires connecting each of the pots together.

Just to double check, I thought I'd place some copper foil (with the adhesive) inside the control cavity of the guitar. After getting the copper in, I check with my DMM and verified that it had continuity among the entire surface. I then screw the ground wire back into place, and check for continuity again. Now, I had ground from the pickguard's foil to the foil inside the cavity.

I decided to check out how it sounds plugged into my Marshall (with a moderate amount of crunch), and it still has the same amount of hum as before. Did I do something wrong? Should I check another outlet in the house (will have to wait until tomorrow since it's late)? Would it not work properly because I didn't shield where the output jack is?

Sorry for sounding somewhat moronic. I'm just a bit confused on how I can get the whole cavity shielded, yet it has no effect on the hum what-so-ever.

Thank you, and have a great night! I'll check the thread once I get home from work tomorrow.
Skip the username, call me Billy
The black paint substance was probably conductive paint. It's an easy way to shield the control cavity, fairly common on decently made guitars. So your copper shielding of the cavity was likely redundant, and your noise issue originates elsewhere.

Is it particularly noisy for a strat? If you're used to humbuckers, no amount of shielding (well, within reason) is going to make those single coils sound quiet by comparison. Between the conductive paint, the copper shielding, and the standard pickguard foil, I think you've probably ruled out poor shielding as the cause of the noise. If it's no louder than a similar strat, you may need to either learn to deal with the hum or get some noise-canceling pickups.
Does shielding stop mains hum? I've only ever thought of it as a fix for rf noise - my main problem. Seth's opposing coils are supposed to fix mains hum, and AFAIK modern strats are mostly mains hum cancelling in the 2 and 4 selector switch positions using the same principle. How does yours sound in the 2 and 4 positions?
Roc8995: Yeah, I was half considering that the black paint was conductive paint. I may have redundantly used the copper foil in that instance.

I'll test my set up a few more times, but the thing about my Strat is that it came stock with a Humbucker in the bridge position, and that still is noisy. Even by comparison of my other guitars (all of which have a HB in the bridge position).

Tony: In the 2 and 4 positions, they are silent as I expected. Surprisingly enough, the HB gets some noise in the bridge. As I mentioned above, all of my other HB equipped guitars don't have this hum in the bridge position.

Spellman and Tallwood: Thank you, guys. I'll check both of those out!
Skip the username, call me Billy
I have an out of the box theory then it could be that this new guitar has a higher gain for the pickup(s). Like if I put an invader in a guitar by seymour duncan in contrast with a say 1959 style PAF the hum can just be a hotter pickup.

if so this is an easy solution without getting too technical here's a tip if it's only the bridge pickup that is too hot. Capacitors are cheap from thailand (1$ us dollar/free shipping) and the ones you're using from there do not burn up at high temperatures or require polarization (a specific way)

the jist of this is that you put a capacitor before hot lead (north start) and it filters out a certain % of output from the pickup. Any voltage will do, the capacitance is up to you. 0.01uf to 0.047uf is a good spectrum. Luckily capacitors are like a dime a dozen and easy to work with. the further from the decimal the weaker the capacitor so 0.999uf capacitance is massive compared to 0.001uf which you probably wouldn't hear a difference. But the massive over the top capacitance it would be like you're under the sea

so some ideas of capacitance I'd try
0.01 (not 3 zeros)
0.022uf / 0.027uf
0.033uf / 0.039uf