hard solder 650 degree C what do I need to melt this?

Hi,

I have a hinge on the temple rod of a pair of spectacles that is
broken. I think that it is spot welded on. Is there some kind of
fairly inexpensive tool that would help me remove this?

I would like to remove this and add a fresh hinge. I think that the
frames are some kind of nickel alloy. I was thinking of using this

"Silberfix" hard solder 62% Ag without Cd that has a melting point of
650 C and is suitable for bronze,nickel, stainless steel.

Do you think this would be tough enough? Is there some inexpensive
device that will allow you to solder at 650C?

I found this:
http://www.cybermarket.co.uk/ishop/923/shopscr1664.html
would this do?

And advice welcome. Thank you

I'm in the UK