Paul Raymond on fri 22 oct 04
Hi Ron and John,
I've been doing some work with a few of your glazes and am getting good
results. I can't thank you enough for the book. I have a question regarding
your high Ca matte glaze. You mention in the book that it can be very glossy
if fired without the down firing. Now last night I loaded up the kiln with a
bunch of bowls and stuff for a glaze firing and decided to put some tests in
of the matte glaze though this was definitely a high gloss glaze kiln.
Anyway, I just unloaded and that matte with 6% rutile and 6% red iron ox.
came out fabulous. So my question is, what is your opinion on using a glaze
designed for a matte finish in such a way that it turns out glossy? By
opinion I mean safety issues. Any harm in eating off of it? I think you are
going to say no but I just want to make sure.
Thanks.
Paul Raymond
Franklin, TN
John Hesselberth on sun 24 oct 04
Hi Paul,
I'm delighted you are having success with our glazes. Regarding the
difference in leaching performance between rapidly cooled and slowly
cooled high calcium mattes, I haven't been able to see anything
significant in limited testing. This might seem surprising since the
crystals that form certainly change the bulk composition of what
remains in the glassy phase. I can only surmise that the crystals are
such a small percentage (volume or weight-wise) of the total that the
composition isn't changed enough to matter. It is one of the things I
have on my list to test more carefully sometime in the future, but that
list is fairly long so it may not be soon.
Regards,
John
On Saturday, October 23, 2004, at 01:51 AM, Paul Raymond wrote:
> Anyway, I just unloaded and that matte with 6% rutile and 6% red iron
> ox.
> came out fabulous. So my question is, what is your opinion on using a
> glaze
> designed for a matte finish in such a way that it turns out glossy? By
> opinion I mean safety issues. Any harm in eating off of it? I think
> you are
> going to say no but I just want to make sure.
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ron Roy on mon 25 oct 04
Hi Paul,
No problem - that glaze will be just fine - no toxics to worry about anyway
- You might check for crazing - adding iron oxide raises expansion.
I would like to see a picture of it - if you send a picture to my email
address - just keep it under 100K
RR
>Hi Ron and John,
>I've been doing some work with a few of your glazes and am getting good
>results. I can't thank you enough for the book. I have a question regarding
>your high Ca matte glaze. You mention in the book that it can be very glossy
>if fired without the down firing. Now last night I loaded up the kiln with a
>bunch of bowls and stuff for a glaze firing and decided to put some tests in
>of the matte glaze though this was definitely a high gloss glaze kiln.
>Anyway, I just unloaded and that matte with 6% rutile and 6% red iron ox.
>came out fabulous. So my question is, what is your opinion on using a glaze
>designed for a matte finish in such a way that it turns out glossy? By
>opinion I mean safety issues. Any harm in eating off of it? I think you are
>going to say no but I just want to make sure.
>Thanks.
>Paul Raymond
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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