Ford F-150

I said aluminum; the alloys depends on the percentage of magnesium. And what happens in your fireworks, with other fuels to support the flame, has nothing to do with what happens to a car body that's in a fire.

No, Lloyd. Go back to the original points: I said that you can't sustain a fire in aluminum sheet, plate, or castings in air. You can't do it; the researchers can't do it. It can't be done.

Now, look at what you just said. You said you can burn it in "powdered form." Of course. I pointed that out in one of the earliest messages in this thread. A lot of metals are dangerous and potentially flammable in powdered form. But we're talking about auto-body sheet metal, and other parts. You can't burn them in air.

Aircraft catch fire from time to time. Show us an example of one in which the aluminum caught fire, on its own, without other fuels to support it, and burned up the entire aluminum structure. The same with the hundreds of thousands, combined, of Land Rovers, Jaguars, Audis, and specialty makes that have been made of aluminum.

We aren't talking about fireworks, or any other situations in which aluminum oxidation is being supported by another fuel or propellant. And we aren't talking about powder.

What do you mean by a "stimulus"? I asssume you mean another fuel.

And when you have a combination of fuels burning, and you take the molten aluminum puddle away from the other fuel, what happens? The fire stops. The aluminum won't burn in air without another fuel to support the fire. It won't even burn in pure oxygen at atmospheric pressure.

Ford said nothing about it. It would be a stupid question, because there are hundreds of examples that show it won't burn. The metallurgist was talking about the alloy constituents, not about fires.

Yes.

No, you don't have the facts, Martin.

I don't know what that last sentence means.

As I said in the beginning, wrought or cast aluminum will not sustain a fire. You can hardly burn it by holding a torch on it, and it won't sustain a flame except with oxygen above atmospheric pressure.

You can burn aluminum powder, and you can burn aluminum in a high oxygen environment. What oxidizer do you use in your fireworks - most definitely not just atmospheric air.

Reaction of aluminium with air

Aluminium is a silvery white metal. The surface of aluminium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, aulumium metal does not react with air. If the oxide layer is damaged, the aluminium metal is exposed to attack. Aluminium will burn in oxygen with a brilliant white flame to form the trioxide alumnium(III) oxide, Al2O3.

Reaction of aluminium with water

Aluminium is a silvery white metal. The surface of aluminium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, aulumium metal does not react with air. If the oxide layer is damaged, the aluminium metal is exposed to attack, even by water.

Reaction of aluminium with the halogens

Aluminium metal reacts vigorously with all the halogens to form aluminium halides. So, it reacts with chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively aluminium(III) chloride, AlCl3, aluminium(III) bromide, AlBr3, and aluminium(III) iodide, AlI3.

2Al(s) + 3Br2(l) ? Al2Br6(s)

Reaction of aluminium with acids

Aluminium metal dissolves readily in dilute sulphuric acid to form solutions containing the aquated Al(III) ion together with hydrogen gas, H2. The corresponding reactions with dilute hydrochloric acid also give the aquated Al(III) ion. Concentrated nitric acid passivates aluminium metal.

2Al(s) + 6HCl(aq) ? 2Al3+(aq) + 6Cl-(aq) + 3H2(g)

Reaction of aluminium with bases

Aluminium dissolves in sodium hydroxide with the evolution of hydrogen gas, H2, and the formation of aluminates of the type [Al(OH)4]-.

The sheet metal may not have magnesium in it but I know that some of the engine and accessory parts Ford (and others) have used and still use are magnesium alloy. I've been there at vehicle fires and put them out. On the F-150 the water pump, lower intakes the front accessory mount casting, throttle body castings, steering column mounts, trans covers are just some of the magnesium alloy parts.

On other makes the engine mounts, cowl panels (Mustangs), seat frames, radiator mounts, GM 6 speed trans cases, Corvette engine cradles and roof reinforcements. Jeep since 2011 the entire dash support is magnesium alloy. VW, BMW and others are using magnesium engine blocks, transmission cases, clutch housings.

Nothing like hitting that stuff with water and seeing the fire get hotter, due to the magnesium alloys high temperature actually breaking the water down into hydrogen and oxygen and causing a nice hydrogen explosion.

Wrought or cast magnesium will burn in air. Aluminum will not.

U.S. production cars have had some magnesium parts since at least the '70s. There probably are earlier examples. Magnesium/aluminum alloys have been used by the Brits, the Germans, and the Italians in cars since the 1930s. Some of those alloys will sustain a fire (such as Elektron); others will not.

A lot of auto-body sheet aluminum today is 5000-series. 5052 and similar alloys are used by the big automakers, including Ford. They're around 2.5% magnesium. They will not sustain a fire. Neither will 3003 (no magnesium), which is used for some hand-formed bodies, for specials and the like. Neither will 6061 ( 1% magnesium), which is used on some of the F-150. 7075, like 5052, is around 2.5% magnesium. No torchie, no burnie.

snipped-for-privacy@snyder.on.ca fired this volley in news: snipped-for-privacy@4ax.com:

Does no one read what another writes?

What parts of "in puddles" and "in air" were unclear?

Lloyd

You didn't explain how.

"Steve W."

FYI, water breaks down at 2000 C (3632 F ). Perhaps someone out there is curious enough to want to know this. phil k.

And magnesium burns at around 4,400 degrees F. It really lights things up. Tosses off a lot of UV as well.

"Jim Wilkins" fired this volley in news:mhdf10$5sa $ snipped-for-privacy@dont-email.me:

And therefore, it was totally ignored, instead of someone's asking, "OK, how?"

No... not even ignored, refuted out-of-hand without so much as a direct acknowlegement.

We make a number of fireworks that rely upon oxidizer-augmented heat sources to fuse aluminum and raise its temperature to incandescence. At that point, the hot aluminum can be thrust out into open air - in LARGE droplets (not 'powder'; some of the droplets are a large fraction of an inch across), and it will continue to burn IN STP AIR.

Can a slab of aluminum be made to do the same, just lying on the dirt? Probably not. But our common, daily use of it for that purpose totally refutes the statement that aluminum cannot be made to burn in air.

And that tenet was rejected without even anyone's asking 'why'.

How can anyone make 'blanket statements' about a material without knowing about other industries that use it in a way contradictory to the 'common wisdom' of their own industry?

I'm _particularly_ sensitive to that sort of mindset, just now. This last week, I participated in an Air Force Research Labs 'think tank' concerning "dynamically reconfigurable systems"... weapons and/or methods that can change during deployment to manage changes in environment, strategies, or a change of purpose/goal during deployment.

The first day of the two-day session was spent training the participants to avoid just this sort of automatic rejection of others' ideas, simply because they don't jive with what an individual's personal opinions of them are. Basically, "Somebody else might know something you don't. USE their ideas instead of arguing against them."

Ed can just continue to believe what he wants.

Lloyd

LLoyd

Oh, good grief. We've been talking about wrought and cast aluminum pieces in a car fire, and you're talking about "droplets" ignited from "oxidizer-augmented heat sources," which is NOT BURNING IN AIR! It was ignited in the presence of an augmenting oxidizer, with additional fuel. And then you toss out this already-burning, oxidizer-augmented droplet of aluminum, continuing to "burn" it in air. For how long?

Lloyd, the whole point of this thread is that you can't start aluminum sheet, plate, or castings burning in air. It won't ignite, and it won't sustain a flame.

Now, by the time you jumped in, we weren't going through a description of the entire situation each time. One side was saying that aluminum cars will burn in air, and the other side was saying they won't. Furthermore, you can't start molten aluminum burning in air. You had to start it with an extra oxidizer.

If that wasn't the case, people who cast aluminum in open-flame furnaces wouldn't be able to cast it without flames shooting out of the top of the crucible. I've been there. Flames don't shoot out. But we don't use extra oxidizers, either. Neither does a burning car.

A couple of years ago I was turning a titanium part in the lathe for some snowmobilers and mentioned that it will burn. Hah, they said, no way! So I picked up a piece of swarf and held it with pliers in a propane torch flame and up it went. Needless to say, they were totally shocked! heh heh ...

And if you try to put it out with a CO2 fire extinguisher, it will only burn hotter. There have been cases of titanium turbine parts catching fire in service.

When you heat many metals until they're incandescent, and then "augment" the conditions with an extra oxidizer -- like gaseous oxygen or some oxidizing component of solid-state fuels -- you can do it with steel.

Dan provided a list of metals that will burn in air a week or so ago, and although some of it applies to extreme surface-area/volume cases, as with your titanium swarf, the list is fairly long.

But aluminum cars don't burn.

Ed Huntress fired this volley in news: snipped-for-privacy@4ax.com:

You didn't even read what I wrote THIS time.

I won't argue the point. You know more about it that anyone else in any other industry.

LLoyd

I read it very carefully. You completely dodged the point of the discussion and presented an example that is chemically, physically, and logically unrelated to it.

Thanks, I'll stop carrying aluminum scrap and ammonium perchlorate loose in the back of my truck.

Here's some expert advice on plasma-cutting aluminum that doesn't mention setting it on fire.

When I struck a TIG arc on freshly brushed thin aluminum without turning on the gas I just made a black mess and had to redo the tungsten.

-jsw

I was replying to his "fireworks" comments. Fireworks contain strong oxidizers to burn the metallic compounds to produce the colours, sparks, ansd smoke.

And magnesium burns at 3100c - and someone is going to be curious enough to want to know that too - - -