h a l f b a k e r yYou gonna finish that?
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'Round these parts, a lot of old (and old-style) buildings are
faced with flint. The fields are just full of the stuff, and you
have to use it for something.
Flint melts at around 1000-1200°C, which can be easily achieved
with a hydrogen flame. It should, therefore, be possible to cover
a driveway with a thick layer of flint, and then melt it
lavaesquely. Upon cooling, you would be left with a supremely
hard-wearing driveway.
I know just how he feels.
https://supposedlyf...com/2015/03/zao.jpg
[MaxwellBuchanan, Feb 05 2019]
A short film of Max in his lab
https://www.youtube...watch?v=FnblmZdTbYs
[Loris, Feb 06 2019]
Lava morphologies
https://en.wikipedi...ava#Lava_morphology
You'd probably want a rolling, ropey lava rather than a sharp, prickly lava [notexactly, Feb 07 2019]
Lava driveway
Lava_20wells
Another method [8th of 7, Feb 07 2019]
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Couldn't lava flows in places, which have volcanos,
be diverted into large Thermos style flasks that get
shipped to anywhere in the world where lava is in
short supply? |
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Hard wearing? Flint? You can buy tungsten carbide plates for
a few hundred. |
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Synthetic diamond driveway |
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when the sun hits it at a certain angle, that's going to look
interesting. |
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According to das wikipedia, flint is basically minute crystals
of quartz.
I'm /not entirely/ convinced that melting and resetting it
would get you back a material similar to what you started
with. |
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No, it probably wouldn't, but you'd get some sort of glassy
material. |
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Incidentally, given that flint contains a modest amount of
water, I'm wondering if a microwave might do the job. I shall
report any interesting results. |
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Incidentally, I've seen a video on youtube where someone
tried to make an obsidian sword by
melting it down and casting.
One of the problems they had was that the obsidian
foamed up as it was melting.
Flint and obsidian are created by very different
processes, and they're probably only somewhat similar in
composition, so that may or may not
be an issue. (edit : huh, quartz is SiO4, obsidian is mainly
SiO2.) |
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You'd also want it to be /quite/ a thick layer, or it would
shatter when something heavy like a
car moved over it.
Would it spoil the artistic vision too much to melt it ex
situ in a furnace, then cast into
position? It would be easier to get a consistently well-
melted, even temperature mix.
And probably less collateral scorching. |
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I'm told (by the expert sitting here next to me) that flint (as above //basically minute crystals of quartz// - or cryptocrystalline) melts at 1710°C - the 1200°C melting point cited above would require an added flux. After melting, it would re-set into 'fused quartz' - a kind of amorphous silica glass. If you cooled the driveway very, very slowly, it would set as crystalline quartz. Opal is basically just silica with bonded water, so under the right conditions you could have an opal driveway. |
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//1710°C// Hmm. That's higher than even pure silica. I
think the lower temperature is correct, perhaps because of
impurities that lower the melting point. |
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//melt it ex situ// that would be the sensible option, alas. |
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Incidentally, I am just now microwaving a lump of flint in the
lab microwave. Currently at 115°C after 60s. |
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(1 minute 15s later): 155°C
(another 1 minute 15s later): 183°C
I am beginning to wonder whether internal moisture will
cause this thing to explode violently. But hey - another
minute can't hurt. |
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OK, another minute gets it to 205°C.
And another minute gets it to 222°C, and it is making little
crepitatious sounds. |
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I think this is where a wise person would stop. I have
picked pieces of microwave out of my face before, and it is
less enjoyable than it sounds. |
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The temperature rise seems to be very very roughly linear
with time, which suggests we are getting somewhere. I'm
sure I remember reading/seeing that glass can be melted in
a microwave, but only if you start it off by softening with a
flame - presumably because softened glass absorbs
microwaves but cold glass doesn't. So, I'm not sure what
would happen with my flint. Maybe its internal trapped
water would absorb enough to energy the middle to melting
point, whereupon the melted silicates would absorb more
energy. So then you'd have an ever-hotter molten rock
centre trapped in a splintery, glass-like rock. Which sounds
quite like a bomb. |
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I'll have to try this again when I've got a surplus microwave
and a long extension lead. |
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Why don't you grind it into powder and microwave that?
That should mitigate any inclination it has to brew up. |
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(Disclaimer: don't actually know; no responsibility accepted;
try at your own risk.) |
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////melt it ex situ// that would be the sensible option,
alas.// |
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It does have a bright side.
First consider the relatively humble concrete mixer lorry.
Now imagine the flint liquefying lorry. Bask in it's glory! |
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Oh yes - that is an excellent point. The entire drum would be
glowing a bright yellow, flakes of slag would be dropping off
it, and there would be an intense heat haze rising therefrom. |
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I think it would need full kiln insulation or it wouldn't be
able to
carry enough fuel to melt the whole batch. But perhaps cars
which drove too close behind it might find the paint on the
bonnet would start to smoke and peel off. |
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If you want a fused silica surface, what you're probably looking for is Trinitite. |
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The good thing is that it can be produced extremely quickly, using locally available materials. |
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Yes, but I've heard it can cause unevenness in the surrounding
area. |
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Surely a Laver driveway would be easiest? |
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8th does have a point, creating Trinitite does have its
bright side. |
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// cause unevenness in the surrounding area // |
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On the contrary; guaranteed to produce a nice level surface for several kilometres radius from Driveway Zero. |
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//several kilometres radius// Well, that would take care of
the front lawn and part of the north-east asparagus bed.
However, the Head Gardener (who, it turns out, is a fraud -
he's actually a plant and tree gardener) has expressed
concerns over the sequoias in the north-west greenhouses. |
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According to a somewhat dog-eared but relentlessly optimistic leaflet we've found called "Protect And Survive", a coat of white emulsion paint over regular glass windows will fully protect against megaton-range thermonuclear devices detonating right outside. |
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Everything else will be instantly vapourized, but the glazing will be fine. Oh, how we laughed. Are there any more in the series ? We expected to find other familiar characters like Roger Mellie, Buster Gonad and The Fat Slags, but they're not in it. Shame. |
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// //1710°C// Hmm. That's higher than even pure
silica. I think the lower temperature is correct,
perhaps because of impurities that lower the melting
point.// - well, the Wikipedia page for Silicon
Dioxide says 1713°C so I think I (or rather, the
materials scientist I asked) was right |
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// the materials scientist I asked // |
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You ASKED someone ? Someone who knew what they were talking about ? Shame on you ... that's cheating. You're supposed to make dogmatic pronouncements based on half-remembered and mostly irrelevant facts. |
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Asking an expert is not allowed (unless that expert is you (allegedly)). |
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// One of the problems they had was that the obsidian foamed up as it was melting. // |
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I wonder if glass foam would be more durable than a solid block since it wouldn't crack as easily. |
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//Wikipedia page for Silicon Dioxide says 1713°C// Yes, but
that's presumably pure SiO2. Flint has impurities, which will
probably lower its melting point (just as they do in glass
making; soda glass melts at a much lower temperature than
pure silica). |
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// I wonder if glass foam would be more durable than a
solid block since it wouldn't crack as easily. // |
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I expect it would be softer, but maybe also stronger in some
ways. Softer because each little bit of glass would have less
surrounding glass to support it. |
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Ceramic foams have been the subject of intense research for decades. They offer the prospect of stiff, durable, insulative and cheap (because there's a lot of air in them) construction materials. So far, the major problem -amongst many -is maintaining the homogeneity of the material while it sets (for cement-based mixes) or dries and is fired (for clay-based blends). |
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Glass foam, being a silicate but solidifying from a melt rather than drying or setting, is also being researched but unsurprisingly suffers the same problems. |
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Cadburys, the makers of "Aero" chocolate, have a patented process for forming homogeneous bubbled chocolate from a viscous melt, but attempts to analyse the products have always failed because the investigators eat the test samples. |
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// I wonder if glass foam would be more durable than a solid
block since it wouldn't crack as easily.// |
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It might well be - a non-isotropic version is glass fiber,
produced by extrusion - which can be processed into
composite materials with that property. |
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Hmm, a Cadbury's chocolate drive way, with sufficient
cooling it might work, and really piss small children. |
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A fluffy pastry for you and your molten rock driveway [+]. |
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Pressing dinosaur shapes into the unsolidified muck might
add an air of prehistoricosity. Would there be any way to
add the lingering stench of sulfur? |
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A little further experimentation reveals that: |
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(a) When heated sufficiently, flint spalls off shards of
flint
(b) The velocity of the shards is jolly high
(c) The temperature of the shards is also jolly high
(d) Said shards remain very hot for at least 60cm of their
journey and
(e) Reflexively bringing your hand up to a cheek with shard of
hot flint stuck in it is not helpful. |
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//So far, the major problem -amongst many -is
maintaining the homogeneity of the material while it
sets .// |
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The problem is the air. Totally different density, a
homogeneous mix would be simple to achieve with
the ceramic voids supported by something like
aluminum. If that's a touch pricey, then using
additional ceramic would yield excellent
homogeneity. I've informed marketing of my
invention, bs0-biceramic with molecularly stabilized
co-matrices will be available in 6 standard blends.
Custom orders will be expensive. |
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Round these parts, the day ain't over yet. |
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"It's all fun and games until someone loses an eye ... " |
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It can be fun and games even after that, depending on who's
eye it was. |
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Am I right in thinking this experiment involved a Bunson burner? Was the microwave just too slow? |
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Why don't you try the pre-grinding thing? |
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And maybe wear safety glasses /and/ a face-shield next time. |
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It did indeed. I know a Bunsen fame won't get hot enough
(though it'll melt soda glass), but wanted to find out what
would happen. I did. |
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Pre-grinding - perhaps. Or I might just try some flint gravel,
which might be a bit like popcorn. |
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//maybe wear safety glasses// That would be very, very
dangerous. Protective gear is there in case of a serious
accident. Without it, you can only have fairly minor
injuries. This philosophy has seen me through 57 years of
reckless fate-tempting. But I appreciate the thought. |
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//Bunsen fame// - yes, he *has* acheived quite a
degree of fame |
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"The light that burns twice as bright", shirley ? |
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No, it's fine - just needed a 110V transformer. |
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// Protective gear is there in case of a serious accident. Without it, you can only have fairly minor injuries. // |
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<Downloads 2019 TT Superbike race entry form/> |
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<Starts to fill in form with [MB]'s details/> |
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<Bout of hysterical laughter, ending in wheezing and hiccups/> |
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<Resumes form-filling while still giggling and smirking/> |
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I hope it is ground flat before use. Some lava is
textured like razor-edged pumice with fiberglass bits
sticking out. |
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I hoped this would be an idea to reserve a parking
space by heating it to 1200C |
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//I'm sure I remember reading/seeing that glass can be
melted in a microwave// |
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It can, fairly easily (as long as it's not Pyrex or anything like
that of course, which might just take longer?), I've done it
myself with a coffee jar I was using to
nuke some soil for a sealed terrarium. |
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Oh dear. I think I've just made a connection which will never
be forgotten. Link. |
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Anyone can tell that's not real, [Loris]. [MB]'s specs have square frames. |
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Also, <link> to Prior Art. |
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You of all people, [8th] should know that I wear a monocle.
Especially after the llama incident. I'm just glad we got it
back. |
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