Posting this here to see if anyone can shed light - I'm no beginner but the responses may be useful to others.
So - I have some 60/40 Multicore branded X32C solder that just won't flow, it isn't that old, it's 3 Core 1.5%, 22awg and it simply will not flow out - even if I use a flux pen in addition. It just beads regardless of temperature, whether I use the flux pen or not it doesn't matter (I tried this because I thought that 1.5% may be too little on a repair I'm doing)
I've another roll of similar solder and it works a treat - must be 10 years old but it is absolutely no issue, 325 Deg.
Yes the area has been cleaned, yes the pads have been tinned, yes I'm using a temperature controlled iron (CSI Premier 75W), I've tried temperatures between 275 and 350, I've tried with and without flux pen - this particular roll won't work no matter what I try. I don't think in 30+ years I've encountered anything like it, tempted just to throw it out but I'm too tight fisted to do so (I have 1kg of the stuff ...)
Any suggestions ?