I have been doing more and more soldering lately and want to buy a larger coil of solder. I went the the store today and the loger size has 2 rating for the electical. Well I got to thinking I had know idea which would be better 60/40 or 40/60. Any input would be great. I have been using the 40/60 tin to lead. With no adverse affects. Both inside and out.
60Sn/40Pb will melt at a lower temperature than 40Sn/60Pb. This may be important if you are soldering heat sensitive components, or on circuit boards.
The lowest melting point available in Sn/Pb solder is 63/37. This is the "eutectic" alloy, which goes directly from solid to liquid, with little to no "plastic" mushy phase. This alloy is widely used in electronics work. It melts at about 360 degrees F.
Most important for electrical work is a non-corrosive flux core. You want a rosin flux, not an acid flux as is used for sheet metal or plumbing work.
60sn is what I like but I also follow the "mechanical connection" rule. You are just flowing solder over the connection that is already secure, allowing it to wick into the joint. If you are one of those folks who "build up" the solder connection 40/60 might be better for you since you can work the liquid front. Stained glass folks like that.
Thanks guys. I am soldering LV connections and K&T so some of the positions are a bit odd. So the quicker it melts the better as far that goes. but it sounds like either will due for what I am working on.