Hello

I was wondering if anyone had a problem with 9ct rose gold solder?
I am trying to resize a diamond and ruby ring (going three sizes up) with a fairly fine d-shape shank (about 2mm wide). I have a clean, no gap fit. I placed the ring first in dapping block filled with water, just enough to cover the stones and tried to quickly solder it. At first I used my small hand held butane torch, then moved on to sivert with medium nozzle to no avail. Then I used a cooling gel instead of water this time on a soldering brick and still nothing. The solder melted slightly but not much. I have some experience soldering yellow gold but never rose, so I was wondering if there's a difference. I used medium 9ct red solder bought at Cookson.
I have to add I did heat the ring for much much longer that what I am normally used to (with gold) that is why I find this a little baffling.
I also need to be careful as the ruby, which is the central stone, has a large diagonal brake in the pavilion which extends quite deeply into the stone, so I can really go gung ho with the heat. Especially that it is my customer's precious heirloom...
Any advice would be greatly appreciated!

Monika