Hi
I am suddenly having lots of trouble with soldering 18ct yellow gold rings. I have made quite a few wedding bands like this over the years (1.5mm x 5mm sheet gold)and never had any trouble. However, now every time I gently shape the ring on the mandrel after soldering the ring is splitting along the solder seam. I am quite an experienced jeweller and have tried varying everything I can think of (new solder, different flux, cleaning everything like mad, different heating/ cooling regime) but just don't understand it. I have used the same solder panel as I've used to make previous rings, as well as trying brand new stuff. Sending me a bit crazy!

Any help or suggestions would be very gratefully received!

Thanks
Tom