Lily Krakowski on tue 15 oct 02
there may be newer may be better tests but this is the one I have used all
my clay life. Learned in school.
Weigh a piece of unglazed clay you have fired in your glaze kiln. Cover
with water. Boil it for half an hour or more. Dry off excess water on a
towel and reweigh the piece. If there is a weight difference figure out
the %. That figure is the % of absorption. The accepted rule seems to be
that a 3% weight gain is acceptable in mid-range.
if you have a big kiln that may not fire evenly use several pieces in
different locations to test.
Mary White writes:
> Hi Cat--
> I'm far from an expert, in fact I just did my very first electric
> glaze firing a few days ago. But I was using Cone 6 glazes on Cone 10
> B-mix and it worked just fine. At least the pieces appear fine and
> have already been through the dishwasher a few times safely. I don't
> know how to tell if they're not sufficiently vitrified, actually.
> on the wet west coast of British Columbia
>> Hola! I have a question about using a Cone 10 claybody vs. a Cone 5 when
>> firing Cone 6 glazes. Sorry if its an often-asked question, I canít seem
>> access all the old Clayart discussions. For some reason about half the
>> topics I try to access give me a ďPage cannot be displayed: There are too
>> many ppl accessing the web at this timeĒ (but thatís a whole nuther
>> isnít it?). Anyway, I love using B-mix. I use it to throw and handbuild
>> with minimal problems. I use Cone 10 glazes AND more recently Cone 6.
>> Because of this I like to stick with the same claybody so I donít end up
>> with meltdowns at a higher firing range. This also gives me flexibility
>> deciding what type of glaze I want to use after I have made a piece. Am I
>> asking for too much freedom in the production process this way? My
>> is that when I use a Cone 6 glaze on a Cone 10 B-mix that the clay will
>> insufficiently vitrified for my functional work (mugs, bowls, plates). I
>> have used the Cone 5 B-mix for my Cone 6 glazes and had no problems.
>> Iím going to have to tinkle or get off the pot with this decision and use
>> the different range clays for each glaze process, but I donít want to if
>> donít have to.
>> Thanks in advance!
>> -Cat Yassin
>> S. Texas
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