Sarah House on fri 8 dec 00
I would like to use my cone 10 stoneware at cone six. I followed the
instructions for an absorption test that i found in the archives. I weighed
a mug (unglazed) then boiled for 2 hours. then i dried it off and wighed
again. Used the formula wet-dryx100/dry. I got 0.5%. Then because i had
also read the instructions in The Val Cushing Handbook I let the mug soak
in water for 9 hours and weighed again. The second time it was 1.6%. I was
not expecting such a low percentage either time and wanted other opinions.
i know that clays shouldn't have a very wide range and it seems to be a
very reliable body at cone 10. I do plan to call the company on monday for
their ideas on it.
Thanks,
Sarah House
http://www.skhpottery.com
Ron Roy on fri 15 dec 00
Hi Sarah,
Anything under 3% after boiling for 2 hours will be sevicable. Remember to
cool the clay with runing water after the boiling or evaporation will
affect the results.
In order to get an accurate reading the test should be done as soon as the
clay comes out of the kiln - any clay sitting around will absorb H2O from
the atmosphere and you will not get a true reading. At least weigh the clay
as soon as it comes out of it's firing - or wrap it up in something water
and air proof till you can weight it.
I say weigh it while it's still hot and boil it right after.
RR
>I would like to use my cone 10 stoneware at cone six. I followed the
>instructions for an absorption test that i found in the archives. I weighed
>a mug (unglazed) then boiled for 2 hours. then i dried it off and wighed
>again. Used the formula wet-dryx100/dry. I got 0.5%. Then because i had
>also read the instructions in The Val Cushing Handbook I let the mug soak
>in water for 9 hours and weighed again. The second time it was 1.6%. I was
>not expecting such a low percentage either time and wanted other opinions.
>i know that clays shouldn't have a very wide range and it seems to be a
>very reliable body at cone 10. I do plan to call the company on monday for
>their ideas on it.
>Thanks,
>Sarah House
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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