Did you ever hear of the Pyrolytic Graphite lined pipe for smoking pipe
Released in the 1970's and the graphitic element wa made by SuperTemp in
Seasoning of a cast iron pan produces a high carbon content grease layer
on the inside and you can cook over it.
You can even cook over a charred layer in a metallic pan, or a charred
grill in a BBQ. You would then be cooking on carbon.
Bulk carbon isn't something that your body readily digests.
Great info thanks! Never heard of a Pyrolytic smoking pipe. Sounds
like it would offer a smooth smoke. I'll have to make one (out of the
polycrystalline slab I bought).
Do you recall when pyrolitic graphite became known or sold as such?
Are all "Pyrolytic" graphites grown using CVD?
In the 1950's there was considerable interest in pyrolytic graphites for
rocket and missile uses.
Pyrolytic graphite is much older than that, but probably had very little
I believe it is correct that the convention is to use the pyrolytic
grphite term to denote many of the graphites made by means of CVD, but
you can make carbon products by CVD which aren't commonly called
email@example.com (aSkeptic) wrote in message
I did a google search on the Pyrolytic Graphite pipe you mentioned. I
still have a couple questions that my search didn't answer. I'm not
sure how the PG is encorporated into the pipe. Would the "bowl" (eh
hem.) be made out of the stuff, or would it be the stem or both? I'm
having difficulty imagining the geometry of either a bowl or a tube
because PG is layered in 2 dimentions, not three. You said they were
lined with PG. The only geometry that would make sense is cylindrical.
Did they make a real thin sheet or foil of PG and wrap it into a
TIA for any info you might like to offer,
Do a better Google search next time.
You need to read some real stuff about pyrolytic graphite manufacturing
and then you will understand a lot more.
I am an old fart who was there, and I read paper materials, not web pages.
If you want to actually learn, you may have to go to a library.
I don't do tutorials by typing. Too many illustrations are needed for
clarity and it is a waste of time.
You can also look into the pyrolytic carbon heart valves that for many
years were at least half of the market for artificial heart valves
produced and implanted in the USA.
Your mind has to be able to grasp the geometry of the heart valve and
the CVD process. Then you'll see how useful pyrolytic graphite and
pyrolytic carbons were.
In pyrolytic carbons, there are certain X-Ray diffraction peaks that
can't be resolved but they can be resolved in pyrolytic graphite. The
main physical factor involved is the temperature of decomposition with
higher temperatures being associated with the graphitic form, as was
also true with the bulk electrode business of graphite and carbon
Jack Bokros, possibly now dead, was the major player in pyrolytic
carbons. "Super" Smith of SuperTemp was a major player in pyrolytic
graphites as well as a bunch of technical hotshots at Sandia
Laboratories and a bunch more from GE and still many more people who
have slipped from my memory.
So, go hit a library for honest research.
Your graphite is typically porous, which may induce sticking by the egg
liquid penetrating the pores and then coagulating in-situ.
The bulk specific gravity of the bulk graphite is probably around 1.6
and the non-porous graphite crystal is about 2.25.
Typical porosity, of all pore sizes, for graphite is in the range of
20-40%. Maybe 10% is closed porosity.
Pyrolytic graphite would typically have much lower porosity, only a
percent or so based on dennsity measurements, and the physical sticking
by pore infiltration would not happen.
You likely should expect pyrolytic graphite to have less sticking,
unless you have a specific mechanism in mind that would be stronger with
the specific surface of pyrolytic graphite.
However, I never said that pyrolytic graphite would be non-stick.
WIthout oil, stainless steel will stick to an egg. With oil, the egg
slides around happy as a clam.
It would be technically correct to say that the pyrolytic experiment
should be run..... because you need the data given the number of
variables in the materials and the unknown "sticking" mechanism.
Just trying to bring scientific reasoning into an unscientific empirical
Pyrolytic graphite would be a worse skillet surface because of it's
poor thermal conductivity on the C plane (worse than alumina). On the
A-B plane it's probably much slicker than natural graphite. Sorry that
I didn't make that point clear in my last post (--pyro would be worse
from a cullinary POV).
I got a definitive answer to my question by experiment (would it be ok
to cook an egg on a graphite slab?). The answer is: no, the egg sticks
even worse than stainless steel. Experiment cost me $15, including
egg. I have other plans for the slab, including some crude
glassworking experiments, so it won't be a total waste of money. And
besides, it was fun. Tell me you've never experimented on an unknown
just for fun or serious investigation. Theory is just one scientiffic
tool. Experimental and emperical procedure is the bedrock of all
important scientiffic thinking (max plank and blackbody radiation,
Einstein and the solar eclipse of 1919, carot and his working fluids
investigation, Rutherford and Geiger's experimental supprise discovery
of the atomic nucleus, Bridgeman and unsupported packed gasketing...
and so on). Man learns new things by doing. I am aware of the problem
of reinventing the wheel and so on. Yes it is always a good idea to
exhast current literature on a subject before boot strapping an
expensive experimental setup.
Usenet is a great place to get and give leads on ideas. Sometimes I
simply don't know what to search for. I appreciate your input on the
subject, as always.
With enough experimentation an anomaly is bound to contradict theory.
All solids contract on freezing: wrong; gallium, water. Liquids don't
freeze on heating: wrong; see earlier usenet post. Soilds always
expand on heating; wrong, plutonium. Thermal conductivity gets greater
at higher temperatures: wrong; most metals. Elecrical conductivity
lessens at higher temperatures: wrong; TiC etc. Tensile strenght
decreases with higher temperatures: wrong; graphene.
The exceptions to the rule is what makes science facinating and
engineering frustrating. Experimentation is very important for both.
Thanks for the chat. I will go to the university library and order up
some books on CVD (graphite in particular) when I can get away from
this programming gig grounding me to my house. If the library can't
find me the info I'll buy the darned books myself. Science literature
is not cheap :(
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