The Shelfords on mon 13 oct 97
Ron Roy wrote:
>I have a concern here. I know there are many potters that are just
>beginning to get into glaze analysis and I admit to oversimplifying.
>Dragging the many abnormalities of glaze chemistry into the conversation at
>a basic level must only be confusing to most of them. Surely it is
>forgivable to leave out some of the gory details in the hope of promoting
>better understanding of the basic questions.
I hope you continue to do so, Ron. Speaking as one with no chemistry or
even general science background, I have used the glaze calculation program
the way I drive a car - get in and go. It has served very well with that
mistreatment, but questions are bound to arise, as they did on the subject
of the breakdown of rutile. I have really appreciated all the answers,
both simple and complicated. The simple ones, because I have some hope of
understanding them. The complicated ones, because the only way I know to
learn more is to dive into stuff I don't understand and keep letting it
wash over me until it begins to make some sense. Then work from there.
But that's more intellectual exercise. When it comes to getting past real
glaze problems, I need the much more basic help. So please keep it up, and
thank you again to all those who have given time to this question, and are
still giving it.
- Veronica
____________________________________________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
____________________________________________________________________________
Ron Roy on tue 14 oct 97
Hi Veronica,
Thanks -
You bring up something I have been meaning to share - before I started
using calculation software I was faily ignorant of the role of oxides in
clays and glazes. I found the more I got into the molecular formula
approach the more I had to learn about the oxides we use. To my surprise I
found it interesting - in fact facinating to a degree I could not have
imagined before GCS (glaze calculation software.) The journy is expensive
in time and a good library is a must - but - if it wern't for quick and
accurate calculation I would never have done it.
>----------------------------Original message----------------------------
>I hope you continue to do so, Ron. Speaking as one with no chemistry or
>even general science background, I have used the glaze calculation program
>the way I drive a car - get in and go. It has served very well with that
>mistreatment, but questions are bound to arise, as they did on the subject
>of the breakdown of rutile.
>- Veronica
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
David Hooker on wed 15 oct 97
I've been working in this presentation over the last year (so I'm an
admitted novice), but so far the best approach I've found has been to
describe every thing that's in a glaze in four catagories: glass, flux,
"sticky"(clay), and other (colorants, opacifiers...etc). I then take the
class through the glaze lab and help the students put the basic glaze
ingredients into the catagories (explaining that feldspar, which is
basically used as a flux, can fit into the other catagories). Once they
have this basic understanding they start to make pretty intellegent
guesses. (e.g. "so this glaze is basically 60% flux, 20% sticky, and 10%
glass? Can I make a glaze from scratch using this ratio and have it melt
the same?)
Then, of course, you have to get into glass/flux ratios, which always
manages to get that "deer-caught-in-headlights look." Basically, from
there, I just make them make the damned glazes instead of guessing all the
time.
Anyone have other suggestions?
Curious,
David JP Hooker
dhooker@ns1.upstate.net
David JP Hooker
dhooker@ns1.upstate.net
turn 'em and burn 'em!
Ron Roy on thu 16 oct 97
Hi David,
I wonder of you include in your description of the oxides some sort of
expansion/contraction information? Most (well all) of the texts I have give
no idea about the fit possibilities of glazes offered. Seems to me it is
important information.
If you can hold your breath a bit I plan an article on the use of
calculated expansion compared to measured expansion shortly.
How do you handle assessing the durability of glazes?
>----------------------------Original message----------------------------
>I've been working in this presentation over the last year (so I'm an
>admitted novice), but so far the best approach I've found has been to
>describe every thing that's in a glaze in four catagories: glass, flux,
>"sticky"(clay), and other (colorants, opacifiers...etc). I then take the
>class through the glaze lab and help the students put the basic glaze
>ingredients into the catagories (explaining that feldspar, which is
>basically used as a flux, can fit into the other catagories). Once they
>have this basic understanding they start to make pretty intellegent
>guesses. (e.g. "so this glaze is basically 60% flux, 20% sticky, and 10%
>glass? Can I make a glaze from scratch using this ratio and have it melt
>the same?)
>
>Then, of course, you have to get into glass/flux ratios, which always
>manages to get that "deer-caught-in-headlights look." Basically, from
>there, I just make them make the damned glazes instead of guessing all the
>time.
>
>Anyone have other suggestions?
>
>Curious,
>David JP Hooker
>dhooker@ns1.upstate.net
>
>David JP Hooker
>dhooker@ns1.upstate.net
>
>turn 'em and burn 'em!
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
| |
|
