So I think I worked out why I was having trouble with my #soldering
last night... Someone tell me if I'm going crazy here, or if this sounds plausible
The solder I have doesn't seem to have flux in it, because no amount of melting it ever produces any white smoke. However, if I cut through it with a sharp knife I do still see what I think is an inner core that looks "different" - still grey, but less shiney than the outside. I also observe that I need to get the iron quite hot on the temp. control in order to melt new solder off the reel, but having melted it once and let it cool into a ball, I can remelt that at a much lower temperature; even at a temperature which will not
melt fresh stuff.
I think therefore, that what I have is 63/37 solder comprised of a solid core of 37% lead, surrounded by a jacket of 63% tin - needing, therefore, to be hot enough to melt each on their own the first time, at which point they mix and alloy themselves together into the actual eutectic mixture.
Does that sound plausible?