[TheForge] plastic forge? OT:

Mon Jun 13 15:41:13 EDT 2011

Of course!

Oxygen is a gas at room temperature and pressure.  Silicone is a solid
melting at about 2500*F.  Silicon dioxide (aka quartz or silica) is a
solid melting at about 3000*F - a covalent compound of the three
atoms.  And there are much more dramatic examples than this.

Sodium is a low-melting metal (~208*F).  Chlorine is a gas at room
temperature.  Sodium chloride is a solid salt melting around 1500*F.

The difference is that metals like tin and lead, typically don't
combine chemically -- forming new molecules or salts -- whereas oxides
like quartz are distinctly new entities, molecules.  In some respects,
a molecule is like an extended atom -- the electrons are shared
between the nuclei.  Salts are rather the opposite -- the electrons
are not shared, but rather passed completely from one to the other,
resulting in an electric charge that keeps the ions together (unless
stabilized by a polar solvent, like water).  Hence, property changes
can be pretty dramatic.

A couple more thoughts:

A material can "resist" energy (i.e., photons) by reflecting it or
transmitting it (i.e., being transparent to it).  In addition to
reflecting energy, a material can fluoresce -- absorb photons of one
energy level and emit those of a lower energy level.  All these
mechanisms could account for a substance surviving in the presence of
intense energy.  Not all of them are useful for all purposes.

On Mon, Jun 13, 2011 at 1:43 PM, peter fels <artgawk at thegrid.net> wrote:
> In the interesting model you propose, the functional limit is the temperature at which the "glass" breaks down...even if the carbon core were to remain stable up to then.
> The magical plastic alleges to exceed the limits of it's constituent elements incredibly ( literally).
> In metal alloys, a combination of elements tends to lower the melting temperature.
> Are there high temperature compounds where the opposite is dramatically true?
>
> On Jun 13, 2011, at 4:40 AM, Bruce Freeman wrote:
>
>> Rather than wonder about this magical substance that notably has never
>> been commercialized, why not brainstorm to find something or some
>> things that fill some of those functions.
>>
>> There are, for example, a number of ways to resist heat.  Most
>> refractories (graphite being a notable exception) that resist heat by
>> virtue of high melting point and being oxides (impossible to further
>> oxidize).  Others are ablative -- sacrificial.  Graphite almost falls
>> into the last category, or maybe does.
>>
>> Suppose you try to use bituminous coal as a refractory.  Get it hot
>> enough and it expands into breeze (coke).  It fails at that point
>> because it starts to burn, but what if it were somehow protected from
>> burning by a refractory "glass" layer.  Hence, composite something
>> like bituminous coal with some sort of high-temperature
>> oxidation-resistant substance.  What's neat about this is that the
>> breeze would then act as an insulator, protecting what's beneath.
>>
>> What you want to do is to form your "clinker" right on the surface of
>> the breeze.   So, this all gives rise to the question of why
>> bituminous coal does not already act as a refractory.  I suspect that
>> probably relates to properties of the breeze vs. the "glass".  Maybe
>> the glass won't "wet" the carbon?  Maybe the continual degassing of
>> the coal breaks the glass layer, making it ineffective as a "flux"?
>> Maybe the glass sits on the outside of the breeze only, leaving the
>> open "gas bubbles" exposed to the air blast?  Solve this problem and
>> you might develop.  Even light microscopy could help determine the
>> facts, and scanning electron microscopy would probably solve it in no
>> time.
>>
>> Of course, graphite is mainly of interest because of it's high melting
>> point.  Perhaps the equivalent behavior could be obtained using more
>> standard ceramics.  But the "plastic" nature of our hypothetical
>> material is now conceivably a problem.  How does one form a ceramic in
>> a plastic manner?  Well, cement comes to mind -- castable or rammable
>> refractories.
>>
>> All just brainstorming.
>>
>> On Mon, Jun 13, 2011 at 3:11 AM, peter fels <artgawk at thegrid.net> wrote:
>>> It's hard to refrain from thinking of different applications for it....
>>> sorta like relations with  a harbor Fright catalogue when i was poorer.
>>>
>>>
>>> On Jun 12, 2011, at 3:27 PM, Mike Spencer wrote:
>>>
>>>>
>>>> I posted a note to uk.rec.sheds (chiefly because someone had used the
>>>> word "gubbins" and the Starlite guy recounted calling his product
>>>> "gubbins" when first encountered) and had this reply:
>>>>
>>>>    From: bobharvey <robertharvey at my-deja.com>
>>>>    Subject: Re: Sheddi Taxidermy
>>>>    Newsgroups: uk.rec.sheds
>>>>
>>>>    Ah yes.  Starlite.  I recall reading almost exactly that article
>>>>    some 20 years ago in some engineering journal.  It included a
>>>>    photo sequence of someone stirring molten steel with a stick, then
>>>>    putting the stick in a bucket of water without the normal
>>>>    dangerous consequences.
>>>>
>>>>    I always assumed it was all true, unlike the "combustion engine
>>>>    that runs on water" man, who used to pop up occasionally.  'cos It
>>>>    was clear that that was bollocks.
>>>>
>>>> If it's bogus, at least it has staying power.  If it's not, why can't
>>>> I have some?
>>>>
>>>> --
>>>> Michael Spencer                  Nova Scotia, Canada       .~.
>>>>                                                           /V\
>>>> mspencer at tallships.ca                                     /( )\
>>>> http://home.tallships.ca/mspencer/                        ^^-^^
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>>
>>
>>
>> --
>> Bruce
>> NJ
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-- 
Bruce
NJ