So a big piece of ballast just fell of a NASCAR in the Watkins Glen Nationwide race.

I'm wondering, how much denser than lead is tungsten? Is it more workable? Safer in some way?

Also how much more expensive is tungsten than lead?

What properties make it worth the extra money?

Hi
AFAIK the density of lead is ~11g/cm^3, Tungsten/Densimet is ~19 g/cm^3
Tungsten is much harder/stiffer then lead and can be used as a "stressed" part in some applications.
You can maschine it and cut threads into it, you can make components out of it which (for example) where made out of steel or alloy before (helps with packaging)
it is extremely heat resistant
It´s a lot more expensive then lead

spot price on metal exchange lead: ~2.00-2.40US$/kg
tungsten: ~30.00-40.00US$/kg

Some more informations can be found here:

http://plansee.com/tungsten-densimet.htm

About 70% more dense.

No, it's very tough.

Tungsten dust produced from grinding or machining can be very harmful to your lungs. (eg. Mallory metal used for crank balancing is mostly tungsten and should never be machined dry)

Very very very much more expensive.

The higher density means it's physically easier to accommodate a given mass on the car.

I've heard of depleted uranium being used too, but having checked its secific gravity, I can't think why it would be used instead of tungsten, unless it is cheaper - not usually a concern in F1!

DU is (was?) used as ballast in aircrafts mostly, to keep the trim balance within parameters. I doubt it would be used in a racing series given how cars tend to crash and burn. As for costs I've heard reports that it is cheaper than Tungsten for making kinetic projectiles in military applications (but tends to cause health problems, both for those doing the delivery and those receiving it).

Imagine being an F1 driver who has to sit atop a pile of DU for eight-ten hours every other weekend. Poor balls. If cost is not a concern F1 teams would go for tungsten, for sure.

IIRC it was mentioned some years ago that Renault used DU for balancing the crankshafts in their F1 engines.
Not sure if this was/is true or not, but it was stated in some car/racing magazines at the time.


one article to that effect (true or not ?/dunno) can be found here:

http://www.grandprix.com/ns/ns02353.html

maybe also of interest:

Trim weights in aircraft

Aircraft that contain depleted uranium trim weights (Boeing 747-100 for example) may contain between 400 to 1,500 kg of DU. This application is controversial because the DU may enter the environment if the aircraft were to crash. The metal can also oxidize to a fine powder in a fire. Its use has been phased out in many newer aircraft. Boeing and McDonnell-Douglas discontinued using DU counterweights in the 1980s. Depleted uranium was released during the Bijlmer disaster, in which 152 kg was lost, but an extensive study concluded that there was no evidence to link depleted uranium from the plane to any health problems.[55]. Counterweights manufactured with cadmium plating are considered non-hazardous while the plating is intact.[56]

I guess even in the relatively low-tech NASCAR Nationwide series they use tungsten as well. Looks like it's at least an order of magnitude more expensive but in absolute terms it must not be prohibitive.

What's the density of DU?

DU - 19.1 g/cm3, W - 19.25 g/cm3.

In grassroots US racing ( old NASCAR and modern sprints/modified) the standard ballast used was/is barbell weights AKA cast iron.

Not entirely silly as they are available, cheap and pre drilled. Also as they are thin the CG when mounted horiziontaly just below the chassis rail is pretty good.

Lead is useless as ballast. It's cheap and heavy, but that is where the advantages end. It's so soft that you can't bolt it down, any fastener will tear through it in a crash.

It's also really hard to machine, it just clogs any tool you touch it with...

That's what weight boxes are for. With lead ballast, you need a ballast box with a bolt-on lid. As an added advantage, more weight is placed right where you want it. The rules might limit removable ballast to say, 200 lbs, but the weight box is 1/4-in steel and weighs 60 lbs and it's not removable ballast, it's welded to the frame.

I hope nobody would drill a hole through a chunk of lead and attempt to bolt it to something. That would be stupid. Don't know why anyone would try to machine lead for ballast. It's too easy to melt and recast in any shape you want. If you really must machine lead, you want to start with a lead alloy suitable for machining. Many nuclear fixtures are made in this manner. "Pure" leads are too soft to grip in a mill vise or lathe chuck with any security.

In NASCAR the ballast bars (both lead and tungsten are used) are more or less brick-shaped and slide into ends of the frame rails, which are rectangular steel tubing. Then they are secured with plates, pins, and fasteners, which is where this episode seems to have gone wrong. There is nothing more dangerous than ballast thrown out on the track surface. Whatever is unfortunate enough to run into or over it will get messed up big time. I expect someone got a trip to the trailer and a fat fine for this one. That is the usual outcome.

Quite so. Also, a length of 3-inch thick-wall black iron pipe with threaded caps on both ends. It may be filled with lead shot. If you ever saw an old drag car with a rear bumper that appears to be made from chrome-plated plumbing, that's what's going on there. Also, 120-lb truck battery in the trunk. Also, deck lid and frame crossmembers poured with molten lead. And so forth.

Long ago I drag raced a car with a mfg'ers shipping weight of ~3350 lbs. The allowable removable ballast was 200 lbs. The car raced at over 4200 lbs. Nobody thought this the least bit odd; it was simply how the rules had evolved. It's not terribly difficult to hang weight on a car as compared to say, removing it. With a little imagination it's easy to build a driveshaft safety loop that looks perfectly normal but weighs 50+ lbs.

I did lol when I read that!

Tungsten 19.3 g/cm^3 and roughly 1000 MPa, generally non toxic
Uranium 19.1 g/cm^3 and roughly 400 MPa, considered toxic, radiologic toxicity if ingested
Lead 11.3 g/cm^3 and roughly 20 MPa, considered toxic

Tungsten (which is swedish for heavy stone) metal is quite expensive and for high density applications it's usually alloyed with nickel, iron and/or copper with densities typically between 16 and 19 g/cm^3. These sintered tungsten alloys are generally much cheaper and more ductile than pure tungsten and is also much easier to machine (pure tungsten is very hard and difficult). Typically these alloys are high strength (700-900 MPa), and are available in mil spec grades which can be suitable to applications where high strength is required such as bolt on tungsten counterweights for crankshafts. If I recall correctly I paid around €400/m for 20 mm bar tungsten heavy alloy which is about €65/kg, but that was a number of years ago.

Depleted uranium is the leftover from uranium enrichment, it has a high U238 content. U238 is a weak alpha emitter so from a radiological standpoint it is not dangerous as long the metal stays outside the body. Depleted uranium in metal form with a coating on the outside is for instance completely safe. Uranium does however have pyrophoric properties in powder form or in thin slices which can make it a risk. The advantage with uranium is it's low cost as there are practically few applications for it.

Lead is cheap but is a very weak, soft and toxic metal. Only really suitable to low cost applications. Its low melting point (327 degC) makes it suitable to melting and pouring in hollow structures.

At various times DU has also been used for crankshaft counterweights in large radial aircraft engines, helicopter rotors, boat keels, and even as countermass in forklift trucks, incredibly enough. And undoubtedly as race car ballast here and there in years past, but only through lax industrial practices and the exercise of remarkably poor judgement. The Grandprix.com item reads like typical F1 journo-hype; I wouldn't place any credence in it. Of a piece with fancy tire gas, lightweight racing fuel, etc. Today, DU is commercially available, sort of, but not without generating curiosity as to what you intend to do with it among certain regulatory agencies with no apparent sense of humor.

Assuming Edlund's figures are correct, the DU would be less dense than Tungsten. But the article claims the DU is not only denser, but more expensive.

Wanna buy a cheap Russian submarine?

http://www.international.gc.ca/gpp-ppm/inf...s.aspx?lang=eng

JE was correct. Densimet, often loosely called Tungsten, has a density of around 17.5 g/cm^3, so is a little lower than DU. Otherwise, DU is (read used to be) much cheaper, much more easily machined, & available in convenient stock sizes.

Much is made of the radiation hazards of DU, largely because it is used in armaments that disintegrate on impact, scattering fine particles that can be inhaled. However, if I remember correctly, DU as a solid does not emit much more than an igneous bedrock.... I used some to make TMD's (using the current jargon) in.. 1979, I think. I am still around, last time I looked, anyway.

BTW, "depleted" doesn't mean it is "spent" nuclear fuel. It simply means that (most of) the more fissile U235 has been separated off.

p.s. According to Wikipedia, it is (or has been) used as a radiation shield.

You made Tuned Mass Dampers out of DU? Cool.

Evidently lead is "bad" according to the RoHS restrictions that are floating around these days. I'm sure thatr if you touched some (lead) you'd simply drop dead.

I must stop licking my pencil...

Uhm ... auto-fellatio? Say it isn't so ...?

(sorry, couldn't resist)

Well the GIs in my old 'Commando' comics used to shout 'Eat lead' at the Germans just before they all fell down dead. Must be fairly bad for you if one bite can kill.

We did a lot of stuff in '79 we wouldn't do today. We know better now. The danger in DU is not radiation; it's simply toxic as hell when ingested -- as in fumes or particulate form. Not surprisingly, the data on human exposure is not terribly complete, but the controlled animal testing is conclusive. Bad stuff -- a neurotoxin and a carcinogen, among other things. In a race car, the use of DU would needlessly expose drivers and safety personnel to a known serious health hazard. As a result, DU is banned by most major sanctioning bodies and all I can say to that is good.

With hazardous materials and shop practices, I never know how to interpret statements along the lines of "I did it and I survived." We've all done a number of unwise things and gotten away with them. That doesn't mean we endorse them.

Yep, N=1.

Absolutely for the first part. "We know better now" is always true, of course and will evolve with time, not always monotonically.....

McG, would you care to expand on your last claims? My contribution is this.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819790/

http://www.mdpi.org/ijerph/papers/ijerph2006030016.pdf

http://www.kahea.org/lcr/pdf/Depleted_Uranium_Fact_Sheet.pdf

Encyclopedia of Occupational Health and Safety, Third (Revised) Edition, Volume II, Technical Editor Dr. Luigi Parmeggiani, published by the International Labor Organization (ILO) 1983, ISBN:92-2-103289-2, Geneva, Switzerland.

Depends where you are in the process. Out on the finished product end of the chain the risks are fairly low. The people who work in battery plants, not so much.

I have made a series of judgmental and morally superior noises here in this forum, which I have no right to do. I've been one of the worst over the years and was late to come around -- around 12-15 years ago. For example, no one cursed and swore more than me when leadless body solder, leadless electrical solder, and lead-free engine bearings arrived. They are a nuisance and a pain, do not seem to work as well, require special attention, more work, etc, and I always took the self-interested view: Why are the Environmental Police doing this to me? These lead products present little hazard to me. Well, it was never about me. It's about the health and safety of everyone in the chain who has to handle the stuff. Now it seems that everyone in the lead business these days is doing their best to get out of it, and for people in general that's a good thing.

We've had a pretty good idea for more than a century now about the health hazards of heavy metals -- mercury, lead, uranium, et al -- but we have spent much of the century in active denial of that knowledge. Slowly, slowly we come around.

My father was a pathologist, and his only - as far as I know - out-of-hours job was monitoring the staff at a local battery plant, especially from the smelting department. Everyone gave samples on a regular basis, these were checked and drugs administered when necessary. Decades earlier I imagine that no-one was checked, but just got ill.

Can't beat a bit of the old HB...

You are correct, and FWIW I agree.

FYI I was being sarcastic.

Thats ok Mac, you can just run down to the drags and still get your kick of nitro fumes....

McG: Your references certainly present a compelling argument against the use of DU in armaments. Whether it might be appropriate to use DU elsewhere is rather more debatable, in my view.

The planet contains many things that can be dangerous to human beings, including a significant proportion of the flora & fauna. Likewise, many (most?) of the products of human endeavour can be dangerous, including all forms of transportation & the services that are usually taken for granted.

So, whilst I respect your opinions (& would fight for your right to hold them), I don't think that everything that could endanger human life should necessarily be destroyed, buried or put aside. I do accept, however, that the human race has a duty to behave responsibly, & that duty is often neglected in the headlong rush for advantage or profit.

However, returning the topic under discussion, it would appear that the use of both lead and DU in F1 are currently forbidden by article 15.1 of the Technical Regulations, whilst tungsten alloys are expressly permitted.

I wouldn't disagree with any of that. I think perhaps we come at the matter from opposite ends to mainly meet in the middle. The argument that substances are safe because they are naturally occurring has always baffled me. Toadstools are naturally occurring but we don't eat them. Concentrations are also an issue. Water is by all accounts very good and necessary for you, but at levels above nostril-high becomes problematical.

...one thing that can be seen, I believe, when we take a truly objective view, is that the current state of environmental health science is relatively primitive. We don't know nearly as much as we often pretend to. Asbestos and lead are very good examples: In these cases the alarmists and doomsayers were absolutely correct. We manufacture assurances in studies for various potentially hazardous materials that seem to show very low incidence rates -- say, some relative handful of fatalities per hundred thousand. But as the science advances and we learn the causal relationships between these substances and their associated illnesses, we are going to learn these statistics were relatively meaningless. They don't accurately reflect proximity, concentration, or cumulative effect, only more generalized exposures over broader populations (in part because we don't fully understand the mechanisms) nor do they reflect the fact that there is a wide variation in vulnerability to these materials -- cellular nanoprocesses, for example, and genetic predispositions -- among different human beings. Two people work next to each other for 20 years; one contracts Mesothelioma while one does not. We don't know why; we are only now developing the faintest glimmer of an understanding.

So here is what we are going to learn over the coming decades: That when we send people out to work and live in many of these environments, far from guaranteeing their safety with these assertions of extreme improbability, we are actually signing the death warrants for those people who are sure to become afflicted. We just don't know who and how many as of this moment. What can we do about this? Act responsibly and cautiously; respond and react to each advance in knowledge instead of fighting them every inch of the way, and keep learning all we can.



That is my understanding as well. It's my personal opinion that lead ballast in race cars does not represent a serious health or safety hazard. However, the prohibition does reflect the current movement to phase the material out of the automobile industry at large to whatever extent possible.