I soldered a 24k gold band using 22k solder, and the resulting ring is pretty nice.
Join me on this science experiment for a wild ride of learning what not to do.
The ring is 2.33g of pure 24k gold and a tiny fraction of a gram of 22k gold solder, so the resulting karat is somewhere around 23.995K. I LOVE FRACTIONS!

00:00 prep and design talk
02:06 melting an ingot
03:25 drawing wire rolling mill
04:42 pulling round wire drawplate
06:41 setting up the ring
08:58 soldering
10:42 solder joint clean up
11:50 hardening and sizing
12:26 burnishing and polishing
13:10 recap