Interesting visitor....
 

On Wed, 3 Dec 2008 21:15:50 -0800, "CalifBill"
wrote:

If you heat aluminum in the presence of oxygen in first melts and then
begins to do something which closely resembles burning at very high
temperatures. After glowing red very brightly, it turns into a
powdery ash within seconds.

I'd call it burning, purists may not.


It might be burning, but will it support combustion like wood or magnesium?

In the presence of the right oxidizers it absolutely will.

The thermite reaction for example which will burn through almost
anything:

2Al(solid) + Fe2O3(solid) ---- 2 Fe + Al2O3

or as rocket fuel:

6 NH4ClO4 (oxidant) + 10 Al = 5 Al2O3 + 6 HCl + 3N2 + 9 H2O

http://www.aerospaceweb.org/question...on/q0246.shtml

More he

http://oai.dtic.mil/oai/oai?&verb=ge...er =ADA425147

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"Wayne.B" wrote in message
...
On Wed, 3 Dec 2008 21:15:50 -0800, "CalifBill"
wrote:

If you heat aluminum in the presence of oxygen in first melts and then
begins to do something which closely resembles burning at very high
temperatures. After glowing red very brightly, it turns into a
powdery ash within seconds.

I'd call it burning, purists may not.


It might be burning, but will it support combustion like wood or
magnesium?

In the presence of the right oxidizers it absolutely will.

The thermite reaction for example which will burn through almost
anything:

2Al(solid) + Fe2O3(solid) ---- 2 Fe + Al2O3

or as rocket fuel:

6 NH4ClO4 (oxidant) + 10 Al = 5 Al2O3 + 6 HCl + 3N2 + 9 H2O

http://www.aerospaceweb.org/question...on/q0246.shtml

More he

http://oai.dtic.mil/oai/oai?&verb=ge...er =ADA425147



Hey, it ain't rocket science. Oh wait, I guess it is. Nevermind.

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Wayne.B wrote:
On Wed, 03 Dec 2008 18:42:37 -0500, "Reginald P. Smithers III, Esq."
wrote:

Aluminum does not burn
And just how would you describe rapid exothermic oxidation then ?



Very fast spreading and destructive rust.

If you heat aluminum in the presence of oxygen in first melts and then
begins to do something which closely resembles burning at very high
temperatures. After glowing red very brightly, it turns into a
powdery ash within seconds.

I'd call it burning, purists may not.

Sounds to me like rust on steroids.

Interesting visitor....
 

On Thu, 04 Dec 2008 00:57:41 -0500, Wayne.B
wrote:

On Wed, 3 Dec 2008 21:15:50 -0800, "CalifBill"
wrote:

If you heat aluminum in the presence of oxygen in first melts and then
begins to do something which closely resembles burning at very high
temperatures. After glowing red very brightly, it turns into a
powdery ash within seconds.

I'd call it burning, purists may not.


It might be burning, but will it support combustion like wood or magnesium?

In the presence of the right oxidizers it absolutely will.

The thermite reaction for example which will burn through almost
anything:

2Al(solid) + Fe2O3(solid) ---- 2 Fe + Al2O3

or as rocket fuel:

6 NH4ClO4 (oxidant) + 10 Al = 5 Al2O3 + 6 HCl + 3N2 + 9 H2O

http://www.aerospaceweb.org/question...on/q0246.shtml

More he

http://oai.dtic.mil/oai/oai?&verb=ge...er =ADA425147

Did you ever see that Mythbusters episode where they tested the theory
that the Hindenberg was actually painted in a type of thermite and
that's what caused the devastating fire?

They pretty much proved it could have happened that way.
--

Happy Holidays and Merry Whatever It Is
That ****es Liberals Off.

Interesting visitor....
 

On Wed, 03 Dec 2008 19:17:23 -0500, BAR wrote:

Your qualifications as a Naval architect and your degrees in all areas
of engineering are duly noted. Why don't you write a letter to Secretary
Gates and tell him to tell the Navy to start building them out of wood
again.

John Wayne had a wood warship. 150 foot, 2 1/2 mahogany over aluminum
frames. Special nonmagnetic Detroit Diesel 12V149's. [Canada wanted
150 000 for one like it in 2000.]

Casady

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On Wed, 3 Dec 2008 13:09:30 -0500, "Eisboch" wrote:

Quite a few modern naval ships have steel hulls and aluminum
superstructures. They just aren't supposed to crash into an aircraft
carrier.

You can buy strips of metal consisting of two strips, one aluminum and
the other steel, welded together with pressure from high explosives.
You weld one side to the steel, the other to the aluminum. The better
alternative to rivets.

Casady

Interesting visitor....
 

On Wed, 3 Dec 2008 11:27:14 -0800, "Calif Bill"
wrote:

I think the Sheffield was mostly steel and the aluminum in question was a
high magnesium content alloy.

Probably no more than 5%. The stuff, and copper as well, harden
aluminum as carbon hardens iron.

Casady

Interesting visitor....
 

On Wed, 3 Dec 2008 14:59:08 -0800, "Calif Bill"
wrote:

Magnesium does a rapid exothermic oxidation.
A chemist would probably say that it burns with a brilliant white
light. They use it in flares.

Casady

Interesting visitor....
 

On Wed, 3 Dec 2008 14:59:08 -0800, "Calif Bill"
wrote:

Magnesium melts. One of the
reasons it is so hard to weld magnesium.

You are saying that melting makes things hard to weld?
I say it is quite usual to melt the metal while welding, although
there is pressure welding, below the melting point, sometimes even at
room temperature. And it isn't hard to weld magnesium. You simply
surround the arc with a blanket of inert gas, helium or argon.
Nitrogen and carbon dioxide are not inert enough, magnesium will burn
in either.
I have a welded magnesium extension ladder, and I once ignited a small
sliver of it. It burns with a brilliant white light.

Casady

Interesting visitor....
 

On Wed, 3 Dec 2008 11:28:46 -0800, "Calif Bill"
wrote:

The problem with lots of the aluminum ship structures was bad design. Lots
of cracks happening. So better designers were needed. Harry maybe?

Actually, since aluminum and steel have the same strength to weight
ratio, it would seem that someone heard rumors that aluminum is
lighter, and designed it that way. Lighter is weaker. Duh.

Casady