I need to make up to maybe 400 such rings for my King boiler. The problem is that I have several types of 55% or similar, 1mm thick silver solder from different manufacturers but most of them will not bend to an inside diameter of 3.2mm or so, but are too brittle and break at a diameter well above this. I do have one 1.5mm rod that will bend like this but I don't know the manufacturer.
Suppliers I've tried are not able to help in this regard.
Does anyone know of a source for suitable silver solder?
Ive used 1mm silverflo 55 from Mac Models. No problem winding it up like a spring and sniping off the rings and flattening them.
You can anneal silver solder rod, but I have never done this, plus I like the rings to remain tight and springy on the stays so they dont move and also stop the stays moving whilst assembling and fluxing up.
I have had this problem. Some silver solder is a bit brittle and will not bend to make a small ring. So, what I have done is to anneal the solder before bending. It was just something I suspected and it worked. I have a roll of solver solder that is some new old stock. It is way too brittle to make rings from. So, I played a propane torch on a single loop of the roll just to see what would happen. As I played the torch on it, the loop uncoiled just a bit. Obviously don't get it hot enough to melt it, just enough to see the loop uncoil a bit. It should be much too hot to touch. I did it right on the concrete floor of my shop. After the coil cooled, I polished it up a little with steel wool. I brought the now annealed solder back to my lathe to see if I could make a spring from it and wound around the mandrel with no problem.
I then cut the silver solder "spring" into single rings for my stays. My stays are a little bit larger than yours, 3/16" in diameter. But, my solder broke into little bits before annealing just like yours. My solder diameter is 1/16". I don't know if what I have done has actually annealed the silver solder or not. But, the end result is that it now bends easily. YES!