Dear Alma & Noel,
Hoover and Strong (www.hooverandstrong.com) make a new 21k gold hard
solder. I have not used it so I do not know how well it works. Not
enough alloy can be added to make suitable solders for 22k and 24k
gold so fusing is required. Fusing makes a perfect color match and the
seam will be just as malleable as the surrounding metal. Best wishes.