Wipe solder

I got some lead a few months ago and while sorting through it I ran across this.
Attachment 223107
I assume it has tin in it, anyone want to venture a guess on how much!
It weighs about 3lbs.

All of my solder bars are 50/50, and are marked as such. In the absence of those markings you could carefully measure the weight, and the volume, then do a little math to figure it out.

The reclaimed solder joints from plumbing prior to melting the entire piece has been a little over 30% tin. That means I probably melt a little of the lead trying to recover too much of the solder.

A quick site search finds a post by Bruce 381 on 5-17-2016 that says he has several ingots of Bell wiping solder and his xrf done at work shows it to be 40-60 solder.

The wiping solder that I have seen that was marked was lower in tin than most other solders. 60%PB - 40%SN down to 63%PB - 37%SN are typical. For some reason wiping solder is often not marked. Nice find!

A few years ago some of our underground network guys gave me some bar solder and it was a mix of everything. Some 60-40, 50-50, 40-60. By then our company was not installing lead cable any longer, only maintaining what was in service. Along with the cable being fazed out, the skill working on it was becoming a lost art.

I researched this and came up with a telephone company study that the best wiping solder was between 37%-40% tin. with 37% being better than 40%. I just figure it as 40/60 as I have several myself.

Upon my own research I came across this Bell Labs study a while back from a1940 study.

http://www.freepatentsonline.com/2247559.html

http://www.bell-labs.com/our-researc...ations/289167/

"The most satisfactory composition for a wiping solder from practical tests has been found to be about 38 per cent tin, 62 per cent lead. A solder containing 40 per cent tin also possesses satisfactory handling qualities and is used to some extent."

All of my wiping solder is 40% tin and 60% lead


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Early in my plumbing trades I wiped a lot of water connections and drainage as well as flashings area drain bases and the wiping solder was 40/60 and some had a higher tin count like 95/5 for a lower melt temp for thin like 1/16" sheet lead I never have seen small 3# ingots like yours. All my wiping solder came in 25# chains.

lead sheathed phone lines were soldered together. Wiping solder has a liquid stage when it can be "wiped" onto the joint and solidifies almost instantly when a certain temperature is reached. The act of wiping it I believe caused near instant cooling to a solid state. It melts at a much lower temperature than the lead being sealed. Wiping solder is eutectic or nearly so. That is it turns from liquid to solid at one temperature without the transition stage where some is solid and some still liquid. That transition temperature is much lower than either component (lead & tin) on its own.

Aside from being a nice chunk of tin it is a piece of history, as well as a reminder that lead was the plastic of its day. Mine is way down on my list of stuff to throw into a melt.