Help with checking of alloy-mix please

[Black Wolf]

I picked up some 40/60 (tin/lead) solder at the store. In order to correctly mix 10lbs of #2 alloy, I need to mix this ratio:

9.5 lbs of WW's
.5 lbs of solder

...to get roughly a #2 alloy. Am I right?

The solder says that each roll is 1/4 lb of 40/60. That means two whole rolls of this stuff and I was thinking that seems like a lot. This will be my first time mixing this up so I wanna be right. Thanks in advance for any feedback.

[montana_charlie]

To start with, we need to be sure you have the solder you say you have. General purpose solder for electronic work is 60/40. Back when I was in that field, I thought that meant 60 parts lead to 40 parts tin. But I have come to believe that was in error. (Luckily, I didn't need to know what was in the solder, I just needed to use it correctly.)

Today, I am not sure there is solder made that is 40 percent tin...as you say yours is.
Please confirm your solder contents.

It's too bad you didn't find 50/50 solder instead. There is a very straight-forward Lyman #2 recipe on the LASC site that calls for 9 pounds of WW and one pound of 50/50.
CM

[alamogunr]

Today, I am not sure there is solder made that is 40 percent tin...as you say yours is.
Please confirm your solder contents.


CM

There most definitely is 40/60 solder. I have several rolls I salvaged at work before I retired that are marked 40 Sn/60 Pb. It is not more than 4-5 years old. The specification we used when it was purchased made it clear that it was to be 40% tin and 60% lead. It may be that it is special order since we ordered a large quantity. We used it to sweat component parts together on electrical power items that conducted up to several thousand amps. I didn't write the specs but I'm sure it was to make sure there were no point contacts that could overheat in use.

In another thread there was discussion about the position of the numbers designating percentages of tin and lead. It has always been my belief that the number to the left of the slash is always tin.

[Black Wolf]

It's marked Alloy: 40/60 on the roll of solder. An MSDS of this indicates specifically that it is 63% tin and 36.65% lead. Found here: http://www.setonresourcecenter.com/msds/docs/wcd00026/wcd0266a.htm#SECTION_I_-_Material_Identity