@Kyresti I think SAC305 is that, it's just that it always makes bad joints and doesn't flow well. I think you can also get a version with a bit of antimony mixed in to reduce copper dissolution
SN100C (a tin-copper-nickel-germanium alloy) seems to perform a bit better, but it still has the universal problem among lead-free solders of too high melting point; all the ones with low melting point involve expensive bismuth or indium
-F
@Kyresti sorry solder metallurgy appears to be a particular interest of mine (ours?) so i can end up rambling about it a bit
-F
@Kyresti soldering in general is something we have Opinions on; i think anyone working a trade develops Opinions about the tools they use every day (we're not really a tradesperson as much as just, we end up hand-soldering boards we design a lot, because professional assembly services are Expensive for prototypes and small runs)
-F
@Kyresti (SN100C is a little hard to find at present because the patent on it only expired like last year, but you can find it from chip quik as "CQ100Ge germanium-doped solder", which is what we use in the lab. it's nice! still needs high temperature though and more prone to bridging than 63/37, but that could be our technique)
-F