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David C Kuhlman ohiodave at cox.net
Mon Jun 13 22:34:18 EDT 2011



-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of peter fels
Sent: Monday, June 13, 2011 6:11 PM
To: Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] plastic forge? OT:


On Jun 13, 2011, at 12:41 PM, Bruce Freeman wrote:

> 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.

Then is there a handy, refractory  salt of high melting temperature metals
or elements?
> 
> 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
> ______________________________________________________________
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