Stop in for a cup of coffee

Trying google and the rabbit hole is too big.........................

Solder, I want to solder a 12 gauge wire to an alligator-style clip for the ground for my gas tank. What type of solder and size would I need?

This is the clip I ordered. I want to do this...................

View attachment 1716264305
A mueller 27. Best there is. I sold them on the tool truck for almost 3 decades.