Peggy Heer on tue 20 oct 98
Hi Ron...so when you are trying to learn INSIGHT, ...if the #'s refering to
expansion are high...does that mean that there is lots of expansion or
contraction? If they are low...does that mean that there is little
expansion or contraction? I understand the concept of exp. and contraction
in glazes/clay bodies but have never really understood the #'s game on the
Insight program. Have had Tony's 'INSIGHT' for a couple of years and have
now found the time to explore it...need a lot of help in this area. ;>}}}
Thanks for help on what is probably a dumb ?. ;>}}
As Always in Clay Peggy... who is actually throwing a few pieces now...
and it feeeelllssss sooooo ggooooood. Yes!!!!!
I like solidify
---------------------------------------------
>I have still not heard from anyone who is trying to understand about
>expansion and contraction - the question is - what word would be best for
>describing when a glaze hardens enough to become rigid?
>
Peggy Heer / Heer Pottery E-Mail p4337@connect.ab.ca
52120 Range Road 223
Sherwood Park, AB. Canada T8C 1A7
Phone (403) 922-6270
http://www.ffa.ucalgary.ca/artists/pheer/
http://www.connect.ab.ca/~p4337/
Ron Roy on wed 21 oct 98
Hi Peggy,
Yes - the higher the number the more expansion - on heating - and because
expansion (and contraction) are exactly repressible - the higher the number
the more contraction on cooling.
If a clay has an expansion of say 5 and the glaze on it has an expansion of
6 the glaze will contract, on cooling, more than the clay and craze.
If you want to lower the expansion of that glaze to stop the crazing you
add oxides that have a lower expansion (silica for instance) or substitute
fluxes with a lower expansion (ZnO, CaO or MgO) for the higher expansion
fluxes (K2O and Na2O.)
The tricky part is understanding what kind of glaze you are working with,
in terms of surface and colour response, and keeping those qualities the
same.
A simple answer to a complicated task but basically accurate.
Best regards Peggy - RR
>----------------------------Original message----------------------------
>Hi Ron...so when you are trying to learn INSIGHT, ...if the #'s refering to
>expansion are high...does that mean that there is lots of expansion or
>contraction? If they are low...does that mean that there is little
>expansion or contraction? I understand the concept of exp. and contraction
>in glazes/clay bodies but have never really understood the #'s game on the
>Insight program. Have had Tony's 'INSIGHT' for a couple of years and have
>now found the time to explore it...need a lot of help in this area. ;>}}}
>Thanks for help on what is probably a dumb ?. ;>}}
>As Always in Clay Peggy... who is actually throwing a few pieces now...
>and it feeeelllssss sooooo ggooooood. Yes!!!!!
>I like solidify
>---------------------------------------------
>
>>I have still not heard from anyone who is trying to understand about
>>expansion and contraction - the question is - what word would be best for
>>describing when a glaze hardens enough to become rigid?
>>
>
>
>Peggy Heer / Heer Pottery E-Mail p4337@connect.ab.ca
>52120 Range Road 223
>Sherwood Park, AB. Canada T8C 1A7
>Phone (403) 922-6270
>http://www.ffa.ucalgary.ca/artists/pheer/
>http://www.connect.ab.ca/~p4337/
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
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