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testing for water absorption: standard clays 240 and axner's macca=

updated thu 29 oct 09


Miri Hardy on wed 28 oct 09

bee Mix 5 Clay

In addition to glaze testing, I've been testing two clay bodies for glaze=
fit, general usability (such as throw-ability) and glaze=3D20

The two clays I've tested are both C/6 white stoneware bodies: Standard =
Clays 240 and Axner's Maccabee Mix 5 Clay (WC-
901). .

Detailed information about my experience so far with the two clays is ava=
ilable here:=3D20=3D20

The reader's digest version of my findings:

I conducted water absorption tests as outlined in John Hesselberth and Ro=
n Roy's Mastering Cone 6 Glazes. I repeated the=3D20
test three times (3 different firings, different batches of clay) for eac=
h clay.
The test results for the Axner Maccabee ranged from 1.02% to 1.77% (avera=
ge =3D3D 1.42%)

The test results for the Standard 240 ranged from 4.00% to 4.52% (average=
=3D3D 4.33%)

In their book, John Hesselberth and Ron Roy recommend confirming that wat=
er absorption for one=3D92s fired clay is no higher than=3D20
3% and preferably 1-2%. Considering my results (and some random cracking=
) I don't think I'll be ordering any more of the S-

All the best,
Miri in PR