I too had saved some lead from old cast iron plumbing. Here is what I was given from another T-net member.
The National Lead Co. manufactured more than just lead for the plumbing and roofing/tinning (most old-time plumbers were tinners) industry. The company also produced a line of lead paints using the finest white lead process known as the Dutch method and in 1906 it was hoping to come up with a symbol.
Artist Rudolph Yook came up with the Dutch boy theme in a series of sketches that were refined by portrait artist Lawrence Earle in 1907. Earle was passing through his neighborhood in New Jersey when he spied Michael Brady, a young Irish lad, playing in a yard and knew immediately that his search for a model was over!
Arrangements were made: wooden shoes, blue coveralls and the cap were purchased, and Michael was asked to wear them for a few days so they'd look natural on him. His playmates had great
fun at his expense until they discovered he was being paid the princely sum of $2 per day, which in 1907 bought great gobs of candy and soda pop for him and his friends. He consumed so much himself that, by the third day, he became ill and the family doctor was summoned to diagnose a mysterious stomach ailment!
The National Lead Co.'s offices were located at 111 Broadway in New York.
Michael E. Brady was so awestruck by the experience that he grew up to become a famous political cartoonist who was published in the Brooklyn Eagle. And that's how a young Irish lad became the Little Dutch Boy we saw stamped on our bar solder and that you'll still find on Dutch Boy products.
It has less radiation or something. I will try to find it. Search lead sheathing. It has to be at least 60 yrs. old.
lead mined pre 1945, sells for around $13 per oz. It's called low-alpha lead, and is used in electronic soldering. Google "low-alpha lead" for more info. Here's one interesting link.
http://www.petting-zoo.net/~deadbeef/archive/879.html
I heard a bizarre rumor this morning. A sales engineer from a solder company was visiting, and somehow we got to talking about the weird solder that they have to use for C4 flip-chip. Because the solder takes up the CTE mismatch between silicon and whatever substrate you mount your flip-chip on, a special high-lead alloy (95% Pb/5% Sn) must be used. This alloy is viscoelastic at operating temperature, so it provides the give that prevents the flip-chip from tearing the solder joints apart. But you can't use just any lead for flip-chip. There are naturally-occurring radioactive isotopes of lead present in regular solder. Normally, nobody cares because the DRAM's and other chips that might be subject to soft errors due to alpha-particle radiation are embedded in a package which blocks alpha particles. With flip-chip, though, the solder is right on the chip. So, you must use special low-alpha-particle-emitting lead to make solder for flip-chip. The design rules for flip-chip even include a specification for the minimum distance between the solder and any active circuits on the flip-chip. What the guy from the solder company told me was that there is currently a worldwide shortage of low-alpha lead. He said IBM was practically begging for somebody to sell them low- alpha solder. About 10 years ago, IBM did a massive survey of all the lead mines in the world, and they bought one that had extremely low levels of radioactive lead. That mine was exhausted about two years ago. And when IBM went back to looking for low-alpha lead, they discovered that Intel had beaten them to it. He said Intel had bought up all the sources of low-alpha lead, and that they were even buying old stained-glass windows from churches to get the lead out of those! This just seems so bizarre to me, that Intel would be buying stained-glass windows that might be hundreds of years old just to take the lead out to make their next generation of processors. At work, nobody could think of a good reason why the lead from a stained-glass window would be low-alpha, except maybe if you knew that the lead came from a particular mine. This got me to thinking about sources of lead, such as organ pipes and fishing weights. The ancient Romans used lead water pipes. I can just imagine Intel digging up the streets of Rome to get the lead out. I wonder when lead- lined caskets came into use? Maybe Intel could dig up old graveyards? Or maybe they could mine ancient battlefields for lead shot.
The reason for `old' lead being less radioactive than `newer' lead is that when you extract metal from its ore you inevitably mix in air/fuel & stuff with it, and if that stuff is radioactive, the metal ends up rwadioactive too. Environmental radiation levels were considerably lower before 1945, and so metal smelted before 1945 is a good deal less radioactive than metal produced since. Lead from stained-glass windows is such.
For those not familiar with the UK, old churches here often still have lead on the roof. AFAIR, there is a least one company that will offer to reroof such a church free (a massive saving for our somewhat impoverished churches) provided the old roof is pre-1945 and the company can keep the old lead it removes.
Only lead which has been extracted 100 (or more) years ago from the mine is considered to be radioactively inert and good enough for special shielding applications which demand an extremely low radiation background. It all has to do with the decay chains in the lead ore, not with the atomic explosions after 1945. Once the lead is separated from its ore, the decay chain is broken, but it still takes a lot of time for the radioactive Pb isotopes to decay into stable nuclei. Hence the interest in getting very old lead.
I think the reason old lead is better is that the short half-life isotopes have decayed. Lead is the bottom of most of the alpha decay chains, but there are alpha-emitting lead isotopes in those chains. In the ore, it is mixed with other elements decaying toward lead. When you separate the lead, and wait for the short half-life ones to decay, you have low alpha lead. Anyone have a chart of the different lead isotopes and half-lives?
Some years back a Roman galley was discovered by divers with a cargo of lead ingots. Archeologists got to retain the impressed tops of the ingots. The remainder of the metal was merchandized to shielding manufacturers (and now, one presumes the electronics market) at premium price. WWII naval guns and armor plate are likewise of unexpected value. All metal after the 1950s is contaminated with a whole Periodic Table's worth of fallout.
I checked on IBM web site, but way to many forms to fill out just to get any information, so I gave up.
Good Luck, Clayton