I guess I have been very lucky. I have had very little trouble with
it…(yep, watch it now, the bench fairies will zap me…)
But I use mostly medium, and only 1 grade for all my joints. I do a
lot of handmade filigree, with as many as 50-60 joints. Both in
sterling and gold. I use a propane torch, and a homemade borax flux.
I file the pieces to fit flush, line it all up, and use the smallest
snippet of solder I can, and try not to “over flux” the joint. I
also pickle/rinse between each soldering bout. I almost never do
more than maybe 3-4 joints at a time, and usually only 1-2. I also
try to use a small/medium size flame, and “get out” as soon as it
flows. There have also been days, when I burn it all up, and decide
I should go do something else! LOL. aj