Repost: kb6nu.com – Solder: 60/40 or 63/37?

Orginial Post

File this under  ”You learn something new every day.”

A 1-lb. roll of Kester 44 solder with a 63/37 tin-lead formulation is $22.96 from AllSpec Industries. Kester 44 with a 60/40 formulation costs only $21.06.


A couple of days ago, someone on theHamRadioHelpGroup mailing list asked, “So I’m about to put up my first antenna and I need to solder the connectors to the coax. I know learned this in the book but I can not find it, so what kind of solder should I be using?”

Pat, K7KBN, replied, “Rosin core, 60/40 lead/tin (63/37 is better).  Don’t use any acid core or acid flux solder, and avoid the no-lead junk.  The diameter of the solder depends on your taste and experience.  Connector work requires more solder than circuit board work in most cases. And for connectors you need an iron with a massive tip that won’t cool off when you touch the body of the connector like a typical gun tip will.”

So, of course, I had to ask, “Why is 63/37 better?”

The answer? “The 63% tin/37% lead solder alloy is “eutectic” (Google it).  Basically it has NO ‘plastic range.’ It changes instantly from liquid to solid.”

Mark, K5LXP, ever the practical ham, added, “For anything hams solder you would be hard pressed to discern the flow, hardness or durability difference between any of these lead alloys. Hams being hams, 60/40 is usually the cheapest. That makes it ‘better’ right there!”