Some discussants in this have mentioned buying old solder at hamfests, etc. I
do the same, but it is important to read labels carefully. The solder that has
the lowest melting point is (by weight) 63% tin (Sn), 37% lead (Pb). This
ratio also has the same temperatures for "starts to melt" and "completely
melted"; i.e., no temperature range with "pasty" solder. Note well the greater
amount of tin, not lead, because tin melts at a lower temperature than lead.
Note also that tin is more expensive than lead.
60Sn/40Pb melts very close to 63Sn/37Pb, and has only a small pasty range.
Unfortunately, I have occasionally seen "60/40" solder for sale that, upon
reading the SMALLER print, is 60Pb/40Sn. This stuff melts at a significantly
higher temperature than 60Sn/40Pb and has a large "pasty" temperature range,
and IMHO, is a pain to use.
Of course, I'm sure that no one is trying to mislead anyone in order to save a
few cents.
Gene May
WB8WKU
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