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fish bones at cone 10 -

updated wed 23 may 07


pdp1@EARTHLINK.NET on tue 22 may 07

Hi Nathan,

Bones, so far as I know, regardless of who's, are primarily Calcium -
specifically, crystals or latices of
calcium hydroxyapatite...with some Manganese, Magnesium, Phosphorus, Iron,
Zink, Boron, Sulphur, Chromium, Selenium, Silica, and whatever miutely
traces of Heavy Metals which they may absord inadvertantly from
environmental or
dietary sources.

I think it is interesting to realize that the molecules our Bones are so
much composed of, are Metals technically...Calcium being a Metal, of addition to most of the other lesser constituents also being


Bones are considered refractory.

I think thin Bones such as those of a small Fish or other small Animal may
be dissolved at high heats if in combination with other materials that can
for fluxes with them, but I do not know Glaze Chemistry to say what or how
on that.

Ivor would know I am sure, and others...


l v

----- Original Message -----
From: "Nathan Miller"

> 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
> If you're having trouble viewing it, please e-mail me at
> Nathan Miller
> Thistillium Pottery
> Newberg, OR