Tom Quackenbush wrote:
Specifically, how do you know when a lead alloy has reached it's
liquidus temperature?

On another newsgroup, a poster mentioned that the solder attaching
his LED to the PCB melted, therefore he knew that the temperature must
have reached 720 degrees F. I responded, asking what kind of solder he
was using, since 60/40 melts somewhere around 370 deg. F.

I know what the published values for the melting points of various
solders are, bear with me.

Original poster then says, I just measured it, my 60/40 solder melts
at 600 deg. F., what temperature does yours melt at and I don't want
to know what the charts say, I want to know what you measure.

Ok, I've got nothing better to do tonight and how can hard this be?
I've got the ingredients - various lead solders, toaster oven, decent
thermometer.

I hope this is not the toaster oven you heat up snacks in. You will probably
end up with significant lead contamination.