Cindy Gatto on thu 31 oct 02
Hello All:
In reference to a prior post that I put up. Someone replied
asking if we used carbonate or oxide. It may have been a mistake on my part
in not being clear enough in my post but I said carbonate at the beginning of
the post but did not repeat it throughout the post. So to clarify I apologize
I was speaking of carbonate only not cobalt oxide only cobalt carb.
Thank you
Cindy and Mark
The Mudpit
228 Manhattan Ave.
Brooklyn NY 11206
718-218-9424
mudpitnyc@aol.com
www.mudpitnyc.com
John Hesselberth on thu 31 oct 02
On Thursday, October 31, 2002, at 01:45 PM, Cindy Gatto wrote:
> I guess
> what the ultimate question is, could it be that this cheaper cobalt is
> of
> lesser quality, and is this possible?
>
Hi Cindy,
I'm afraid the answer is, yes it is possible. I know nothing of the
quality of U.S. Pigment materials, but I do know there are some low
quality materials out there being sold as cobalt carbonate. Cobalt
carbonates are not all the same. I published a note on Clayart 2 or 3
weeks ago on this very subject. You really need to know your supplier
and do not buy on price alone--particularly for the more expensive
materials. There are several grades of cobalt carbonate, copper
carbonate and rutile being offered--of those I am certain. There may be
others.
I would call U.S. Pigment and insist on getting an analysis sheet for
what you bought. Then call other suppliers and ask for their's. If you
don't know who else to call, try Standard Ceramic--I have always found
their materials to be of high quality. And no, I don't have any
financial interest in them. I think you will find the source of your
problem if you compare analyses.
Regards,
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Cindy Gatto on thu 31 oct 02
Hello All:
A question to everyone. Has anyone ever purchased cobalt
carbonate from US PIGMENT? and if so have you noticed any difference in the
cobalt from US Pigment compared to other cobalt that you have used? The
reason for these questions is that we purchased ten pounds of cobalt from
them at a really good price ($19.00 a pound) and when using it have been
getting different results from glazes that have been made with this cobalt.
For example it seems that the cobalt is weaker, it seems that the colors from
the fired glazes are kinda of washed out like the colorant is weak. I guess
what the ultimate question is, could it be that this cheaper cobalt is of
lesser quality, and is this possible? When we received this cobalt it was
not as purple as past cobalt it was much lighter almost grayed. Any help with
this would be greatly appreciated.
Thanks:
Cindy Gatto & Mark Petrin
The Mudpit
228 Manhattan Ave
Brooklyn NY 11206
718-218-9424
mudpitnyc@aol.com
www.mudpitnyc.com
Ababi on fri 1 nov 02
Another point: I use sometimes the carbonate when I want weaker blue, I mean a
little 0.5 on my test.
Ababi
---------- Original Message ----------
>Hello All:
> A question to everyone. Has anyone ever purchased cobalt
>carbonate from US PIGMENT? and if so have you noticed any difference in the
>cobalt from US Pigment compared to other cobalt that you have used? The
>reason for these questions is that we purchased ten pounds of cobalt from
>them at a really good price ($19.00 a pound) and when using it have been
>getting different results from glazes that have been made with this cobalt.
>For example it seems that the cobalt is weaker, it seems that the colors from
>the fired glazes are kinda of washed out like the colorant is weak. I guess
>what the ultimate question is, could it be that this cheaper cobalt is of
>lesser quality, and is this possible? When we received this cobalt it was
>not as purple as past cobalt it was much lighter almost grayed. Any help with
>this would be greatly appreciated.
>Thanks:
>Cindy Gatto & Mark Petrin
>The Mudpit
>228 Manhattan Ave
>Brooklyn NY 11206
>718-218-9424
>mudpitnyc@aol.com
>www.mudpitnyc.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.
Lee Sipe on fri 1 nov 02
I also purchased cobalt carbonate from U.S. Pigment. It was not
satisfactory. I had to use twice as much as normal to get the same results.
I called U.S. Pigment, they told me to send it back, and stated they would
refund my money. I sent it back, and then purchased the cobalt carbonate
from my regular supplier - Highwater Clay in Asheville, N.C. I was shocked
to receive in the mail another order of cobalt carbonate from U.S. Pigment.
They did not credit my VISA as they said they would. The cobalt carbonate
they sent the second time appears to be the same color I have used in the
past. However, I was disappointed that U.S. Pigment did not refund my money
as they said they would. Use caution in dealing with them.
Lee Sipe
Columbia, SC
----- Original Message -----
From: "John Hesselberth"
To:
Sent: Thursday, October 31, 2002 7:38 PM
Subject: Re: weak cobalt
> On Thursday, October 31, 2002, at 01:45 PM, Cindy Gatto wrote:
>
> > I guess
> > what the ultimate question is, could it be that this cheaper cobalt is
> > of
> > lesser quality, and is this possible?
> >
> Hi Cindy,
>
> I'm afraid the answer is, yes it is possible. I know nothing of the
> quality of U.S. Pigment materials, but I do know there are some low
> quality materials out there being sold as cobalt carbonate. Cobalt
> carbonates are not all the same. I published a note on Clayart 2 or 3
> weeks ago on this very subject. You really need to know your supplier
> and do not buy on price alone--particularly for the more expensive
> materials. There are several grades of cobalt carbonate, copper
> carbonate and rutile being offered--of those I am certain. There may be
> others.
> I would call U.S. Pigment and insist on getting an analysis sheet for
> what you bought. Then call other suppliers and ask for their's. If you
> don't know who else to call, try Standard Ceramic--I have always found
> their materials to be of high quality. And no, I don't have any
> financial interest in them. I think you will find the source of your
> problem if you compare analyses.
>
> Regards,
>
> John
>
> 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.
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