search  current discussion  categories  materials - barium 

cream breaking red and strontium carbonate..question for john

updated thu 2 sep 04

 

Eva Gallagher on wed 1 sep 04

H please.

I use Cream Breaking Rust quite a bit and get the speckling all the time -
the glaze is always an even orangey colour when thin - both on white and
brown clay and the specks just appear when the glaze is a bit thicker. If
too thick they then disappear and you get a even pale cream.
So I think that perhaps the 13% tin may not be dispersing well causing thick
and thin areas or opaque and clear (brown)areas?. As well if the clay is a
bit rough with grog - the glaze may thin out resulting in brown on the high
spots?
Eva
Deep River, Ontario---- Original Message -----

From: "John Hesselberth"
To:
Sent: Tuesday, August 31, 2004 8:46 PM
Subject: Re: Cream Breaking Red and Strontium Carbonate..Question for John H
please.


> Hi Angela,
>
> Until I reread this and noticed you said they were pale on red clay I
> was thinking it was poorly dispersed RIO. Now I would have to say I
> haven't a clue. Maybe someone else does. You might examine them with a
> 10x magnifier and see if they look crystalline.
>
> My suspicion, though, is that it is something that is poorly dispersed
> and you will have trouble duplicating it.
>
> Regards,
>
> John
> On Tuesday, August 31, 2004, at 11:20 AM, Angela Davis wrote:
>
> > I have no idea what causes the specks , they are pale on the red clay
> > and
> > dark on the white,
> > and where they are covered with the Varigated Blue they collect the
> > oxide
> > and go really
> > dark. I like them and hope to be able to duplicate them in the next
> > batch
> > so it would be great
> > to find out what is going on here.
> John Hesselberth
> http://www.frogpondpottery.com
> http://www.masteringglazes.com
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.