Daraburn@AOL.COM on thu 29 apr 04
I wrote recently about my quest for a creamy, pearly white. I had used the
High Cal Semi-matte base 1 Glaze and added 5% superpax. I wrote about small
"dimples" in the glaze. As per John's suggestion I added 5% more frit. It has
smoothed out some ( and a little glossier), but I am now getting a few small
pinholes. Not only that but around the pinholes it is a different white. The
result is a spotted look which is not so noticeable on mugs but very
noticeable on a plate. I screen with 80 mesh. Is that not fine enough? Could this be
due to improper mixing or screening with too large a mesh? John, you
suggested that I might try the Maiolica Glaze and I did and it is very nice, but it
is too white for what I am looking for. Would you suggest that I add a small
amt of another colorant to soften that white? What do you think about tin
oxide as a opacifier and with what base glaze? Lots of questions I know but maybe
someone could help because my testing is really getting expensive. I used
$130 on electricity last month running the kiln for testing! That wouldn't be
so bad if I sold some of it but since I am a perfectionist, well you know.
Dawn in Tennessee with new baby chicks just hatched this week (I loved the
chicken OT)
John Hesselberth on fri 30 apr 04
On Thursday, April 29, 2004, at 06:04 PM, Daraburn@AOL.COM wrote:
> Would you suggest that I add a small
> amt of another colorant to soften that white?
Yes, you can do that. I don't know how much softening you want, but you
might run a line blend replacing Zircopax with rutile, e.g. 16/0, 15/1,
14/2, etc. until you get just the color you want. If you want more
softening try adding a little red iron oxide (or one of its various
forms), but go easy.
Regards,
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ron Roy on fri 30 apr 04
Hi Dawn,
Tin is very expensive but you do get a warmer white - but you don'r have to
use as much - like half the amount (of the zircopax for instance.)
Subbing some rutile for some of the zircopax in the majolica glaze will
warm it up - try 4% for starters.
Better explain how you bisque fire - that may be why you are getting pin
holes. A clean bisque firing will sometimes clear them right up.
RR
>I wrote recently about my quest for a creamy, pearly white. I had used the
>High Cal Semi-matte base 1 Glaze and added 5% superpax. I wrote about small
>"dimples" in the glaze. As per John's suggestion I added 5% more frit. It has
>smoothed out some ( and a little glossier), but I am now getting a few small
>pinholes. Not only that but around the pinholes it is a different white. The
>result is a spotted look which is not so noticeable on mugs but very
>noticeable on a plate. I screen with 80 mesh. Is that not fine enough?
>Could this be
>due to improper mixing or screening with too large a mesh? John, you
>suggested that I might try the Maiolica Glaze and I did and it is very
>nice, but it
>is too white for what I am looking for. Would you suggest that I add a small
>amt of another colorant to soften that white? What do you think about tin
>oxide as a opacifier and with what base glaze? Lots of questions I know
>but maybe
>someone could help because my testing is really getting expensive. I used
>$130 on electricity last month running the kiln for testing! That wouldn't be
>so bad if I sold some of it but since I am a perfectionist, well you know.
>
>Dawn
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Paul Lewing on fri 30 apr 04
on 4/29/04 2:04 PM, Daraburn@AOL.COM at Daraburn@AOL.COM wrote:
> I wrote about small
> "dimples" in the glaze. As per John's suggestion I added 5% more frit. It
> has
> smoothed out some ( and a little glossier), but I am now getting a few small
> pinholes. Not only that but around the pinholes it is a different white.
Dawn, it sounds to me like it might be out-gassing causing your problems.
What temperature do you bisque? And have you tried bisquing higher?
Paul Lewing, Seattle
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