[Clayart] Bill Carty and pinholing [GroupMail]

ivor and olive lewis iandol at westnet.com.au
Tue Mar 11 00:43:04 EDT 2014

If Dr William Carty is on the money with this as a source of pinholing we 
need a temperature profile for the firing.  I  have information classifying 
raw Kaolin a Hydrophobic substance.

Re-postingof the 10th message in

Dr. William Carty at Alfred claims firing  dehydroxylates kaolin (drives the 
water off it).  As a result, he says, the fired surface of the clay is 
somewhat hydrophobic (repels water).  Dipping the ware in water, sponging 
it, etc permits the clay to attach itself to some water (rehydroxylates the 
clay) and renders the surface hydrophyllic again (attracts water).  As a 
result, the surface is less prone to glaze faults. I do not know whether his 
statements are accurate. I have never read this in the published literature. 
I have not tested it personally.  There are other variables, like glaze 
composition, surface roughness of the ware, dust, etc. which would make a 
test difficult.  I have found Carty to be a credible source of such 
information, given that his Ph.D. is in surface chemistry and he has worked 
quite a bit with clay products, but I'm biased because he was my MS
advisor.Good glazing,
Dave Finkelnburg


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