Nathan Miller on sun 20 may 07
As a wood-fire potter, I'm always looking for new and interesting things to
try in the kiln. I remember an incident a few years ago that involved mouse
bones. A mouse had died on someone's plowl (half plate, half bowl) and
instead of throwing it out, they decided to leave it where it was and load
it into the kiln as-was. Upon emerging from the kiln, the mouse had left
behind a shadow of its skeleton, thanks to its calcium deposit. Having not
actually seen this and only heard of it, I still kept it in the back of my mind.
In my most recent wood-firing, which I unloaded this afternoon, I decided to
try this with fish. After eating a couple of trout, being careful to keep
each fish as intact as possible, I loaded two vase forms on their sides and
laid a fish atop each one. As the firing progressed, I was able to observe
these pots from observation ports. I watched as ash collected on the pots,
including the ones bearing the fish, and then later as that ash melted and
began dribbling down surfaces and as cones began to bend, I continued to
observe a persistent bumpity material that remained on the vases throughout
the firing. I remarked at least once, "Geez! What does it take to melt
those things?!"
I expected the organic bits to burn and the mineral bits, probably mostly
iron, manganese, calcium and magnesium, to melt and flux each other and
leave some sort of impressionistic fish shape. When these pots emerged from
the kiln, I found that not only did the fish bones not melt, they didn't
even deform! The front of the kiln reached cone 12 and the bottom rear
reached cone 9.5, with the pots in question having experienced at least cone
8, probably a full cone 10. I did a few Google searches attempting to find
information on the chemical content of fish bones (trout bones in particular
would have been nice, but any fish bones in general would have been
helpful), but to no avail. Does anyone have any info. on the chemical
content of fish bones or at least point me in the right direction? That
would be most helpful.
I've posted images to my Photobucket site at
http://s96.photobucket.com/albums/l166/Thistillium/Thistillium%20Pottery/Wood-firing/May%202007%20Firing/
If you're having trouble viewing it, please e-mail me at nsmheralds@netzero.net.
Nathan Miller
Thistillium Pottery
Newberg, OR
Ivor and Olive Lewis on tue 22 may 07
Dear Nathan Miller,=20
Bones consist mostly of Calcium Phosphate, about 70%. I have a melting =
point of 1670 deg Celsius for this substance. This would probably =
explain your experience.
Frank Hamer predicts that you should have had a "stiff melt" (See "Bone =
Ash") due to Phosphorus pentoxide, Paradoxically, Phosphorus pentoxide =
melts at 582 deg C.
Interesting.
As an off topic aside, we get the occasional Mouse Plague. The buckets =
of drowned mice we collect are used as a raw natural fertilizer for our =
native tree reserve.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Eric Suchman on tue 22 may 07
Aren't fish bones cartilage and isn't the composition different than
that of 'Bone'
liz gowen on tue 22 may 07
I believe sharks have the cartilage and fish the bones. Remember my =
grandma
trying to find something edible with the sand sharks. Said they were all
grizzle.
Are the raised bone areas on the pot hard or will they crumble if
you push on them, like a shell will, when used for stilting a =
pot...turns to
quick lime. I like the look of the spine bones would make a nice design
element.
Liz Gowen
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Eric =
Suchman
Sent: Tuesday, May 22, 2007 10:23 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Fish bones at cone 10
Aren't fish bones cartilage and isn't the composition different than =
that of
'Bone'
_________________________________________________________________________=
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Eric Suchman on tue 22 may 07
You're right Liz, my mistake,
Eric
On May 22, 2007, at 8:57 AM, liz gowen wrote:
> I believe sharks have the cartilage and fish the bones. Remember my
> grandma
> trying to find something edible with the sand sharks. Said they
> were all
> grizzle.
> Are the raised bone areas on the pot hard or will they
> crumble if
> you push on them, like a shell will, when used for stilting a
> pot...turns to
> quick lime. I like the look of the spine bones would make a nice
> design
> element.
> Liz Gowen
>
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Eric
> Suchman
> Sent: Tuesday, May 22, 2007 10:23 AM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Fish bones at cone 10
>
>
> Aren't fish bones cartilage and isn't the composition different
> than that of
> 'Bone'
>
> ______________________________________________________________________
> ______
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>
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>
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Nathan Miller on wed 23 may 07
I knew you people would come through in the pyrochemistry department!
Mudslinging pyromaniacs rule!
>I believe sharks have the cartilage and fish the bones.
Yes, that is correct.
> Are the raised bone areas on the pot hard or will they crumble if
you push on them, like a shell will, when used for stilting a pot...turns to
quick lime.
A little of both. They're not fragile enough that they'll fall off if you
look at them cock-eyed. Yet it took me vigorous rubbing with a gloved hand
to remove the ones on another vase (that was otherwise a casualty anyway).
So they take a bit of effort and pressure to break and remove, but I'd still
consider them too fragile to be viable as-is on work I'd be offering for
sale. I did notice that most of the ribs and other bones connected to the
spinal column had been encased in fire-generated glaze (either from fly ash,
mineral deposited from the burning of skin and other uneaten bits, or both).
>I like the look of the spine bones would make a nice design element.
I like it too. I've been pondering ways to improve upon this, mainly
different ways of making sure the entire skeleton winds up encased in glaze.
Fortunately, it doesn't appear that fish bone is really in any substantial
way particularly "Teflonic," as it were, and as such I should be able to
successfully cover them with a glaze.
-Nathan Miller
Thistillium Pottery
Newberg, OR
Ivor and Olive Lewis on wed 23 may 07
Dear Phil,
Like all the ceramic raw materials available to us they can be divided =
into two basic groups.
There are those substances that melt freely at relatively low =
temperatures which behave as solvents.
There are those substances that are highly refractory and need =
exceptionally high temperatures to achieve fusion but they dissolve =
relatively easily in the ceramic solvents we use.
Alkali metal compounds from Group One of the Periodic Table, especially =
their carbonates and borates belong to the first class. Alkali Earths =
from Group Two belong to the second class, especially their Oxides. =
Seems to apply to Barium and Calcium Phosphates as well, not that many =
of us meet the Barium variety.
Just my simple view.
Best regards,
Ivor
Eric Suchman on thu 24 may 07
Maybe a light spray with sodium silicate or soda ash prior to the
firing wwould help to solidify the skeleton? Just a thought.
eric in oceanside
On May 23, 2007, at 8:41 PM, Nathan Miller wrote:
>
> I like it too. I've been pondering ways to improve upon this, mainly
> different ways of making sure the entire skeleton winds up encased
> in glaze.
> Fortunately, it doesn't appear that fish bone is really in any
> substantial
> way particularly "Teflonic," as it were, and as such I should be
> able to
> successfully cover them with a glaze.
>
> -Nathan Miller
> Thistillium Pottery
> Newberg, OR
>
> ______________________________________________________________________
> ________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
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> melpots@pclink.com.
Nathan Miller on fri 25 may 07
>Maybe a light spray with sodium silicate or soda ash prior to the
>firing wwould help to solidify the skeleton? Just a thought.
> eric in oceanside
Would a sprinkling of sodium bicarbonate work? Or does soda ash have silica
in it too? (I ran out of soda ash while mixing Penn State shino and had to
substitute sodium bicarbonate for at least half of the soda ash content.
I'm not sure what effect that had on the glaze chemically, but it seems to
have done the job.)
-Nathan Miller
Thistillium Pottery
Newberg, OR
Timothy Joko-Veltman on fri 25 may 07
On 5/25/07, Nathan Miller wrote:
> Would a sprinkling of sodium bicarbonate work?
Nathan,
Soda ash is just sodium carbonate, so sodium bicarbonate should do
just as well. But since it's BIcarbonate, there will be a higher LOI
(Loss On Ignition), so you will need a greater volume to get the same
effect as you would with soda ash.
Regards,
Tim
Eric Suchman on fri 25 may 07
There is a small plant that grows here on the salt marsh. It was
once a source of soda ash. when you place it on a tile (and fire it
to ^10) it leaves a glass "outline" of the plant. So I'm guessing
that the sodium in the plant fluxes the plant ash to form a glass. I
don't know anything about the sodium bicarb issue.
-eric in oceanside
On May 25, 2007, at 9:10 AM, Nathan Miller wrote:
>> Maybe a light spray with sodium silicate or soda ash prior to the
>> firing wwould help to solidify the skeleton? Just a thought.
>> eric in oceanside
>
> Would a sprinkling of sodium bicarbonate work? Or does soda ash
> have silica
> in it too? (I ran out of soda ash while mixing Penn State shino
> and had to
> substitute sodium bicarbonate for at least half of the soda ash
> content.
> I'm not sure what effect that had on the glaze chemically, but it
> seems to
> have done the job.)
>
> -Nathan Miller
> Thistillium Pottery
> Newberg, OR
>
> ______________________________________________________________________
> ________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
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