I ran into this problem with the last guitar that I did with QTB wiring. That time I was doing the common ground to copper shielding tape inside the cavity of a guitar. I eventually got it to stick, but it was challenging.
This time I am trying to build the common ground on Callaham aluminum shield. I am using a 40 watt soldering iron, but with a pretty fine tip. I believe I have a good connection with the ring terminal and all the ground wires, but is there a trick to getting solder to stick to the shield? I have already sanded the spot I am trying to attach to with coarse sand paper.
Soldering to aluminum is impossible (unless one knows how to do it).
It can be done if a pool of molten solder can be maintained on the aluminum while a sharp edge of the iron's tip is used to score scratches in the aluminum under the pool of molten solder. The solder will bond to the aluminum scratches SINCE IT IS DONE IN AN OXYGEN-FREE ENVIRONMENT.
Aluminum usually oxidizes so rapidly that it can't be kept clean enough to solder.
However, this takes a substantial amount of continuously applied heat which IS NOT conducive to being done on the thin aluminum shield of a pick guard, even the separate Callaham ones.
Most likely, before you might be successful, you will distort and destroy the aluminum shield.
Well, that clears some things up Far be it from me not to try the impossible....
What is my next best option here for grounding? Is it even required that the common ground be attached to the shield as it is also connected via the ring termnal around the pot. I wouldn't want to go back to pot shells if I didn't have to. Thanks, GB
The ring terminal makes a physical connection to the shielding once you tighten the pot down. No soldering needed. You must however also make a physical connection between the guard's shielding and that of the cavity, by running the cavity shield "up and over", onto the face of the body under where the guard attaches- get it to the point where a few of your pickguard screws will go right through it when you attach the guard.