Alisa Liskin Clausen on fri 10 sep 04
is known as thermite.
>
>I wonder if putting aluminum powder in a glaze and
>firing in an oxidation atmosphere would result in
>reduction effects in the glaze? Care to try it?
>
>Anybody thinking of trying this needs to be very, very
>cautious as aluminum powder is an extreme fire hazard.
>
Dear Earl,
Thanks for explaining more to me. The gray slip washed easily out of
clothing, and I also expect it to fire with an unoticeable color.
The next part of your thoughts sounds interesting. But I do not know how
to handle such an animal, aluminum powder, and since it is such an extreme
fire hazard, I probably will not. What do you mean, that is is a hazard to
store or it will ignite in my kiln?
No, I do not think I will try that experiment. There are some things I do
not experiment with anymore,like obvious toxics.
Lilly, I had bat pins and plastic bat on the wheel head for a long time,
and splash pan. Then one day, I just liberated my wheel head and took away
the pan. Since then I use the rings on the wheel head for measuring bases
and centering. I know, I can draw circles on a bat. I liked using the
wheel without a bat for general throwing. But there are alays advantages
and disadvantages in most things.
thanks for writing,
Alisa in Denmark
Earl Krueger on sat 11 sep 04
On Sep 10, 2004, at 10:53 AM, Alisa Liskin Clausen wrote:
> But I do not know how
> to handle such an animal, aluminum powder, and since it is such an
> extreme
> fire hazard, I probably will not. What do you mean, that is is a
> hazard to
> store or it will ignite in my kiln?
Alisa,
You know those strings of firecrackers that you see
going off in chinese parades. If you break one of
those in half you will see that it contains a small
amount of a silvery powder. That powder is aluminum
and an oxidizing agent. A little bit of it can make a
pretty big bang.
The problem with aluminum powder is with storage.
If it should catch fire it is almost impossible to put
out and will create a raging inferno. Spray it with
water and you will likely get an explosive reaction
since the burning aluminum will steal the oxygen
from the H20.
Aluminum does not exist in the metallic form in nature
because it is so reactive. It was one of the last of
the common elements to be reduced to its elemental
form, and that required complex processes. Even
today the production of aluminum metal from an ore
requires massive inputs of electrical energy.
I read once that it takes something like 20 times as
much energy to produce an aluminum soda can
from scratch as it does to make one from recycled
aluminum.
Isn't it interesting that something we so casually
toss in the trash today was once more
valuable and rare than gold or platinum.
Earl K...
Bothell, WA, USA
Ivor and Olive Lewis on sun 12 sep 04
Dear Earl Kruger,
Given that <reaction since the burning aluminium will steal the oxygen from the
H20.>> Yes, but that is not the part of this reaction which causes the
fire. It is the volumes of Hydrogen that are released. Remember the
Hindenburg disaster?
The problem is even worse with Magnesium. All of the group 2 metals
react directly with water. Pure Aluminium does but it forms a cohesive
impenetrable film of oxide on the surface. This is used to decorative
effect by anodising with a coloured solution
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
.
Alisa Liskin Clausen on sun 12 sep 04
Hello Earl,
Thank you for the explantion.
Yes, it is interesting. I had to reread the post
a couple of times to get it all.
Last night I melted some copper sheets in a glaze and it made
crystals. There copper melted to a grey, silver luster under
Tony Hansen's 20 x 5, and there are clear cyrstals on the surface of
the copper. A sideline experiment, since I am afraid of firecrackers.
Thanks again,
regards from Alisa in Denmark
Ivor and Olive Lewis on mon 13 sep 04
Dear Des,
I recall that when Britain was Blitzed in WW2 the incendiary bombs
dropped were made of Magnesium. The fires they caused were never
extinguished with water because the rate of reaction of water with
molten magnesium exacerbated the conflagration due to the production
of Hydrogen. Dry sand was used to stifle the roots of these fires.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Des & Jan Howard on mon 13 sep 04
Ivor
I seem to remember reading that the fatalities were caused by the
diesel fuel for the airscrew engines, the hydrogen just quietly burned away.
Des
Ivor and Olive Lewis wrote:
> > Yes, but that is not the part of this reaction which causes the
> fire. It is the volumes of Hydrogen that are released. Remember the
> Hindenburg disaster?
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
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