- Atomic Number: 82
- Atomic Weight: 207.2
- Melting Point: 600.61 K (327.46°C or 621.43°F)
- Boiling Point: 2022 K (1749°C or 3180°F)
- Density: 11.342 grams per cubic centimeter
- Latin Name: Plumbum
A soft silvery colored metal that rapidly oxidizes to a dark grey.
Ocassionaly found in nature in its pure form and was known to the ancients.
When people think of heavy things they often thing of lead.
This is ingrained in our society, even among engineers and people that should know better.
There are recomendations for making power hammer rams from tubing filled with lead.
This is one lead use in our community that I address repeatedly.
Use of lead for this purpose is needless and wrong thinking.
Lead is only 40% denser than steel therefore it only requires 40% more steel to make the same mass and radiation shielding as lead.
Lead is soft and cannot support itself in many cases.
Steel can support itself plus much additional load.
Lead is expensive to buy and lead scrap is usually more valuable than steel.
Lead is toxic and transfers to the body by simple contact while steel is nontoxic.
One should wash their hands carefully after handling lead.
Lead poisioning is cumulative over a lifetime.
The only advantages lead has over steel is its softness and low melting point, thus ease of castability.
Due to its toxicity lead is no longer used in many cases including where a soft surface is needed.
Tin alloys have replaced lead where a low temperature melting point is needed such as in solder and pewter.
While there are some places using lead is almost unavoidable, most uses can and should be avoided.
If you need to fill that tubular ram with something then use steel rods and weld them in place.
Simple, easy, non-toxic.
A few decades ago lead was used for a great many things in the shop.
It was used for soft work surfaces by file makers, for backing up detailed repousse' and forming hollow vessles.
Lead was used for bending tubing and soft hammers.
Lead was common in solders of many types including that used for both plumbing and electrical work as well as craft work.
Lead is often a major constituant of bearing babbit.
Lead was added to pewter to make it chaeper and thus much old pewter is good only for decorative purposes, not servring food.
Melted lead baths were used for heat treating and lead is still used in plumbing drain pipes.
Lead white (paint) was also a good high pressure lubricant and was used to lubricate lathe centers. . .
Lead has also been added to both steel and brasses to make them machine more easily.
Today, a few lead spills from casting swept out the door can get your soil tested as high lead and make your property impossible to sell unless cleaned up to meet the EPA's satisfaction. It happens. . .
Lead oxide was also used heavily in paint because it atabilized the oil and made colors UV resistant.
Leaded paints lasted longer without cracking.
Chinese paint makers still insist on lead because of the brighter colors and thus the repeated discoveries of lead in imported children's toys.
Tetra Ethyl lead was used in gasoline to raise its octane thus reduce engine knock and valve clatter. This lead to the brand name and common usage of "Ethyl" for the better "new" gasolines with lead. "Fill 'er up with Ethyl". Almosat all gasoline had lead added to it, the more the higher the octane and price. Despite adolescence logic high octane gasoline burns SLOWER then low octane gasoline. . .
The combination of aging paint and automobile fumes but a large amount of fine lead into our environment and people started to study its effects on humans, particularly children. Despite the sources of lead it was clearly proven that lead slowed early development to the point of retardation in some children. When scientists discovered lead from gasoline in what was thought to be the pristine environment of Antarctica that was the straw that broke the Camels back. It was everywhere! It was toxic and it could make our children retarded. . .
Some of the worse cases of lead retardation was in the children of lead workers who came home with fine lead dust in their hair and on their skin and clothes. Other cases were largely inner city and were believed to be due to crumbling lead paint in old houses and apartments. It was found in these buildings and in the soils in the neighborhoods.
So lead rose in prominence as an environmental pollutant to remove from the environment at all costs. Paint was the first target and over the years lead was removed from paint for children's toys and furniture, to house paint and eventually to almost all paint used in the U.S.
Then lead had to be removed from gasoline. This was somewhat of a problem because modern high compression automobile engines needed high octane fuel to run properly. AND while there was natural high octane gasoline (such as the "white" gasoline sold by Texaco) cheaper grades of gasoline could be made to perform by the simple addition of tetra ethyl lead. Removing the lead was a long hard battle between the auto companies (didn't want to do it), the oil companies (didn't want to do it) and the vocal environmental consumer (so called tree huggers) and the U.S. Congress. Congress and the tree huggers won. . .
Lead has continued to be taken out of more and more products both to remove the lead from the manufacturing workplace as well as the consumer environment. Lead shot is no longer used in hunting ammunition and lead is no longer used to make free machining steels (great stuff).
Lead is still being used for a great many things but if it can be phased out, it will be.
I am surprised that lead fishing weights and lures are still allowed.
Have we gone too far? It is hard to tell. On the whole the public tends to be quite reactionary about such things and then unreasonable fears set in. . .
But there was an interesting study done that has failed get hardly anyone's attention.
Folks studying lead in soils where children were found to have high lead levels discovered an interesting fact.
If you took two identical neighborhoods with the same age structures, the same paints used and general maintenance, one neighborhood could be much lower in lead and children tested there have very low levels of lead compared to other neighborhoods where the levels were the highest. It was NOT the paint. City lots could be tested that never had painted structures on them and the lead levels were almost as high as lots where old houses with lead paint had been scraped and painted over and over again.
It was the proximity to major highways, particularly those big interchanges that were often built over and through many city neighborhoods AND occasionally to old industry such as foundries.
When lead content in soils was plotted on a map it created a perfect road map with highlighted traffic concentrations and an occasional isolated spot where an industry was located.
Should we still use lead in the shop?
I would say, as little as possible and to avoid it at all costs if you have a pregnant female or children in the house.
I would not panic about occasional use of lead solder or a lead hammer.
But any process where you melt quantities of lead should be avoided or kept to a minimum, especially in environments where young children might be present.
This includes working with lead such as casting then going home to young children.
Note that we have had several warnings about melting lead.
When melted at a just pourable temperature it is OK.
But you can overheat lead and create lead fumes that are very toxic which can result in heavy metal poisoning.
- guru (webmaster/editor)
I will weigh in on Lead (PTree).
My background, I have been certified as a Lead inspector and lead risk assesor.
The Guru is very right about mental retardation in children.
It appears from the studies the effects are most severe at ages under 6 years.
Lead is a cumulative toxin, and a risk to all. Once you have your body loaded to the point of health problems, there is not much way to get the lead out, short of chealation therapy, and that has risks and bad times associated with it.
A source not often mentioned for lead in the household is PVC plastic.
Lead and lead acetate is added to PVC as a molding agent.
That film you see on those miniblinds that have been hanging in the sunny window for years? Mostly lead.
Gasoline was indeed one of the main sources of lead in the environment.
Tetra ethyl lead was discovered in the late 20's and early 30's in a trial and error program to stop detonation in Presto-Light Kerosene generator sets. The testing was done at the Dayton electric Labs (DELCO later).
Oddly the first thought was that the Rommanian Petrols, dyed Red were better due somehow to the color slowing the flame propogation. So they tested every dye known and many other chemicals. The standard gasoline used before the Lead had a natural octane rating of US gas about 30-40, and required very low compression ratio's. In WWII Hundreds of millions of gallons of Leaded 115/145 octane gas was burned in aircraft. The tetra ethyl retards the speed of the flame propogation and thus reduces detonation. ( The allies got about exactly double the Hp from the same displacement compared to the Axis, due to the 115/145 octane)
About the only leaded gas sold in the US is 100 Octane LL for Low Lead used in aviation.
Much lower lead levels, and since the military and airlines, the big users now burn kerosene, the issue is much reduced.
Metalic lead sitting there is really not much of an issue.
Lead Fume, that is vaporized lead that appears as smoke and is really vapor droplets that have cooled and solidified but are fine enough to be aerosols are big problem.
Lead solder? Not unless you work with it every day.
Lead from chalking paint, or PVC that is chalking?
Big problem if it gets in the body.
In undesturbed soil not a big risk.
Let kids run in it and destroy the grass, or dig play holes etc? big problem.
The primary risk from lead is if you ingest it, either from inhalling fine dust or eating it.
Kids, especially tots have the instant hand to mouth thing.
Another developing issue is that many studies are linking viloent offender youth to lead exposure in the under 6 ages.
One last tidbit, The lead researcher on the tetra ethyl lead project became quite rich as a founding member of the Ethyl Corp. and continued to work as a researcher. He was the same guy that discovered/developed Freon for Dupont, two wonderful answers to industrial needs that ended up have disasterous results for the environment in the long run. I think Harold Midgley had died before the problems were discovered.
Ptree - Thursday, 03/25/10 19:22:08 EDT
A few years ago I saw an amzing antique toy. It was a small Bunsen burner, a bunch of small toy molds (like cowboys, indians, horses) and a small crucible for melting lead pellets. The whole set up was old, rusty and obviously well used. I was amazed because this was a childrens toy, meaning kids were bored at home (no TV, maybe some crappy radio programs and "grown up" books) and playing with toxic material, changing its state and inhaling copious amounts of lead oxides.
And America has a problem with minute amounts of lead paint on a fake hamster toy?
- Nippulini - Friday, 03/26/10 10:28:55 EDT
Nip, My brother and I had one of those sets. It was very satisfying casting the soldiers and then playing with them. We also used to rub mercury on pennies. I've made it to 76 and still going strong with no ill effects.
Carver Jake - Friday, 03/26/10 10:52:09 EDT
I used to make fishing lures (Pro-Line if any of you have used them).
When the Lead was at the correct temperature there was no problem as the OSHA approved ventilation was more then adequate.
The guys that did the pouring and molding wanted to get their numbers up.
They turned up the heat on the Lead allowing them to pour an extra mold per casting cycle.
This caused a heavy gas that OSHA simply called Lead Vapor.
This resulted in four of our workers ending up in the hospital being treated for heavy metal poisoning.
All but one fully recovered.
My friend Alex Mendoza now suffers extreme daily headaches, joint pain, and memory problems.
He also has had a major change in his overall demeanor and is now easily irritated at/by people, objects and situations.
He is now disabled and has not been able to hold even a part time job to help make ends meet.
This same issue happened to another friend but not as severe.
He works on high performance wheels.
He was heating a specialy made wheel to change the bead angle when he "suddenly smelt something funny, got dizzy and dropped to the ground."
The hospital stated that it was heavy metal poisoning caused by Lead.
After hearing this his boss inspected the wheels and found that Lead was used to fill and weight the bead.
He had massive headaches for almost six months afterwards.
Please be careful around Lead especially when melting or casting.
OSHA approved ventilation is not sufficient if lead vaporizes. This can cause serious and permanent health problems.
Arron Cissell- Thursday, 06/02/05 19:08:34 EDT
Heating, melting or torching lead indoors should never be done except if there is an industrial ventilation and filtering equipment installed in order to pull the fumes out.
Such activity is probably illegal in most places.
Lead poisoning does serious damage to the lungs, central nervous system, and skin. children are even more sensitive.
Their I.Q. drops in a direct proportion to the amount inhaled and ingested.
Lead is absorbed by the body (stored in fats) and little of it is shed.
In other words, lead collects in our bodies after each exposure.
Accumulated body lead can be pulled out of the body by treatment with chelating chemicals such as E.D.T.A. (ethylene diamine tetra-acetic acid for any other fussy chemists on the website).
Hopefully, the treatment should be started before much damage has been done to the patient.
But chelation treatments are very unpleasant.
Lead can be detected by blood tests.
A doctor, can detect ingested lead by looking for a "lead line" seen in the gums, if he suspects lead poisoning.
Lead poisoning is serious stuff.
Please permit me to relate the following story (anecdote).
The well-known American landscape artist Emil Gruppé writes that several of his artist friends had to stop oil painting after being poisoned by lead.
Flake white, a lovely white oil colour is made from lead carboate.
His friends (several of them), regularly soaped their brushes in the palm of their hands after cleaning them with turpentine or naphtha.
He describes how one painter's skin had turned dark metallic.
He died two years later. (yes, lead can go through the skin and get into the blood stream.)
Those artists, from the first three or four decades, of the previous century just past, did not know about the poisonous consequences of lead ingestion.
Today, artist and artisans (in my case metal basher) have no excuse.
Please let me summerise the previous long-winded, melodramatic prose. DO NOT MESS WITH LEAD FUMES.
it's not worth it.
Regards and live long, and well.
Slag - Thursday, 02/14/02 21:45:34 GMT
New lead law,
Beginning in April (2010), everyone remodeling a house built before 1975, will have to use lead safe practices.Hanging plastic is the least. Extensive remodeling requires moving out. Replacing 1 window will cost aprox. 100. extra.
Steve Paullin - Saturday, 03/27/10 19:24:34 EDT
12L14 is hot short - it will give off lead fumes while being reheated for forging.
In addition to the lead it intentionally contains a high level of sulfur to make it easier to machine (Another reason it's hot short).
Personally, I'd avoid it like the plague, unless I was doing some sort of screw machine work.
But then, I'm just a metallurgist who was working on alternatives to lead in free-machining bar stock in 1980. :)
Gavainh - Tuesday, 05/24/05 22:46:13 EDT
||97.91 - 98.7|
||0.85 - 1.15|
||0.04 - 0.09|
||0.15 - 0.35|
||0.26 - 0.35
Lead makes the material, known as 12L14, easy to drill and cut, but its presence also requires that steelmakers follow strict safety measures to ensure that lead fumes and dust don’t endanger workers or pollute the environment. Chips and scraps cut from 12L14 steel parts contain lead and must be handled in a special way.
According the Science News 1999 tin is replacing lead in free machining steels.
Other than the above article and many notices of the patent on the tin bearing steel I could not find more information. So its available, but possibly only if you are a large buyer. 12L14 is still being sold.
One of the shops we dealt with in the 1980's that did some heavy machining for us had sources of heavy flame cut plate in free machining (leaded) steel. Apparently that is no longer available. Matweb also listed a narrow range of sizes for the material.
There is a definite push to get the lead out of steel but until the patent runs out on the tin steel replacement I doubt that it will be very popular.
- Friday, 03/26/10 20:09:09 EDT