"won't the heat from brazing melt the solder? "
I would see that as an issue, but everything else being equal solder releases at higher heat than necessary with the initial application. And you could theoretically use solders with different melting points like 45 and 56 silver, or brass and later silver. However, you can also end up with the badge application being a much higher heat deal than the application of the layers, depending on the thickness of parts etc... I have never done one so those are just issues I would be wondering about while doing them, There are solutions to everything.