Soldering Pt/Ru 950 wire

Hello, I’m wondering what is the best solder to use for making a
ring out of 95% platinum /5% ruthenium wire?

The best way to join it is welding it. If your not up to that, make
the joint water tight, then pinch some very thin pure Pt in the
joint. Get it hot enough to melt the pure, file, and burnish. I like
to hack a piece of wire off with side cutters bend it round until it
sort of fits together and TIG weld it. Then I hammer it into shape
and end up with a perfect, seamless ring. Who wants to fuss around
fitting a solder joint! This method works with other precious metals

I was advised to use hard solder, so I tried using the 1400. No
luck. I am using propane - maybe this isn’t appropriate? Solder
seems to melt but the joint cracks when I try to shape. Help?