Rose metal solder

[mitaux8030]

Extending on a bit from my reworking BGA devices post...
Have done a bit of practice in removing considerably larger BGA devices than I will ultimately need to work on, and it's going well so far. Cleaning up the PCB lands is a bit harder than first thought though - managed to pull one land off completely on my practice PCB. It probably was an unconnected pad, but I'd rather aim for perfection than mediocrity.

I've seen a technique where the PCB lands are soldered with very low melting rose metal (90-ish degrees) to form an alloy with the solder already present on the PCB that has an overall lower melting point than the standard 180 degrees, and then remove with wick at a lower temperature.

There's low melting point indium based solder, but that stuff melts around 150 degrees. Not a huge improvement over standard 60/40 at 180 degrees, hence the preference for 90 degree rose metal.

Not having much luck finding a source of rose metal (sometimes called rose's metal) in Australia. Best I can find is some ebay suppliers out of Ukraine. Any hints on a supplier?

[wotnot]

Rose metal alloy is 50% bismuth, 25–28% lead and 22–25% tin. Its melting point is between 94 and 98 °C

...melting point 58C

Chip-quik make a few different low melt solder alloys with different melting temps ...Mektronics stock most of them.

It's not cheap stuff, so use it sparingly