stephani stephenson on tue 1 may 07
Hi Ron!
yes, when i worked over at Alchemie i observed this,
though since there was always something green in the
kiln, never could be sure it was from the brick, but
that was my gut feeling.... no tin ,period,
nowhere.....
any idea if this residual burns out at a certain temp?
i have heard that people fire higher to 'burn out'
lead from kiln interior, i.e fire the kiln empty to a
certain temp... and i wonder if this will work with
chrome, and possibly copper....I have heard mostly
anecdotal info on this, so wonder if someone knows
for sure.
thanks much!
and i wonder if there is something in the chemistry
of a tin glaze which can 'block ' this
blushing....someting tto do with 5 , etc...... thoug
at times it produces lovely effects, if you like rosy
shades!!!
hope spring blooms are showing up in the northland by
now!
Stephani
Ron wrote:
Hi Stephani,
I can get even more complicated - when the fuming
happens it coats the
inside of a kiln and furniture as well - in the end
all you need is a tin
glaze to get pink because every time the kiln is fired
the fumes are
produced again.
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Timothy Joko-Veltman on wed 2 may 07
On 5/2/07, stephani stephenson wrote:
> and i wonder if there is something in the chemistry
> of a tin glaze which can 'block ' this
> blushing....
Stephani,
Sure is: w/o CaO, Cr-Sn won't turn pink. Mg, on the other hand, will
"block" it.
Regards,
Tim
Ivor and Olive Lewis on thu 3 may 07
Dear Timothy Joko-Veltman,=20
You say in answer to Stephanie Stephenson's request for ways to prevent =
kiln contamination
<"block" it.>>
What does this mean? I ask because some years ago I used a Dolomite semi =
mat glaze that gave an inexplicable, but very attractive, red blush.
Can you explain why such a refractory material as Cr2O3 evaporates or =
sublimes so readily?
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Ron Roy on thu 3 may 07
Hi Stephani,
My guess is that you would never get it all out - but - if no more was
added - and you were running a vent - there would be less. Most of it would
wind up condensed on the duct work between the kiln and the outside. Easy
enough to test for in the case of chrome and lead and manganese for that
mater. Just have any ware tested in a lab - anything fuming will be right
on the surface.
Reminds me of the warning I once read - don't vent a kiln near your
vegetable garden.
I'm not sure just how dangerous all this is - and I respect the decision of
those who decide it is not worth worrying about - as long as they don't
make that decision for others - more specifically - me.
RR
>Hi Ron!
>yes, when i worked over at Alchemie i observed this,
>though since there was always something green in the
>kiln, never could be sure it was from the brick, but
>that was my gut feeling.... no tin ,period,
>nowhere.....
>any idea if this residual burns out at a certain temp?
>i have heard that people fire higher to 'burn out'
>lead from kiln interior, i.e fire the kiln empty to a
>certain temp... and i wonder if this will work with
>chrome, and possibly copper....I have heard mostly
>anecdotal info on this, so wonder if someone knows
>for sure.
>thanks much!
> and i wonder if there is something in the chemistry
>of a tin glaze which can 'block ' this
>blushing....someting tto do with 5 , etc...... thoug
>at times it produces lovely effects, if you like rosy
>shades!!!
>
>hope spring blooms are showing up in the northland by
>now!
>
>Stephani
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Ron Roy on thu 3 may 07
Good suggestion Tim - all the chrome tin stains recommend a high CaO glaze
to get the colour.
This does not change the fact that the chrome is still there on the surface
however.
RR
>On 5/2/07, stephani stephenson wrote:
>> and i wonder if there is something in the chemistry
>> of a tin glaze which can 'block ' this
>> blushing....
>
>Stephani,
>
>Sure is: w/o CaO, Cr-Sn won't turn pink. Mg, on the other hand, will
>"block" it.
>
>Regards,
>
>Tim
>
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Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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