Marta Irvin
Heat does not travel well through platinum. If the diamonds only go
half way around the ring, you should have no problems fusing the
shank or using 1700 solder.
For soldering near the diamond such as adding a crown, all platinum
solders have too high a melting point. You will need to use white
gold solder. I recommend 19k or 20k white weld. Make certain you
have a tight fit and use as little solder as possible.
Brad Simon
http://www.BWSimon.com
Dear Marta,
As Brad say, heat does not travel well through platinum. And if you
want to keep the diamonds cooler, you can use a paste (I don’t know
the English name) that prevents heat travel. You can also protect the
diamonds by rolling them with wet Kleenex.
For soldering silver you have to heat around the soldering point
because heat travels well through silver, but for soldering small heat
conductive alloys such as plutinum and gold you can solder only
heating the soldering point. So you should use very narrow torch for
soldering. And I recommend to use white gold for safety.
Takashi Tomoeda
@Takashi_Tomoeda