A nickel is the other ratio: 25% nickel, 75% copper.
The silver color can throw you. I once cast 10,000# of lead into sailboat ballast. Giant propane blast burner, using a steel cauldron on a pivot that I welded up. 100#, two ingots, at a time. Quite memorable. Did it by daylight and at night, and this thread causes me to recollect the amazing color tricks that lead makes as it heats to liquid and beyond.
(You need a lot of “superheat,” or degrees of heat above the melting point, for successful casting on big pours.)
Did you ever see a freshly landed ocean fish like a mahi/dorado/dolphin? The fish, not the mammal. They “flash” through many vivid “metallic” colors as they’re landed and they’re perishing. So did the molten lead, going through bright silver, gold, bronze, green etc.
I’m not sure if this is related to why a 75% copper “nickel” is silver in color, but it’s interesting.
I’ve poured keels a few times. Had to use several quarts of heavy weight motor oil as a flux to be sure the layers would solder together.
It does a pretty good show of colors as it smooths out, especially with the oil.