Kenneth D Wetfall on thu 12 dec 96
A fellow clay person called to day to ask if I was have any problem with
lime pop out coming from Hawthorn Bond fire clay. I presently am using
A.P. Green fire clay, so I said I would put it out to you all and see if
any one else mite be having problem. The folks at Cedar Heights told him
that it was coming from the Maryland refractory Grog. He has sense then
has mixed grog with some clay from various bags and fired test tile with
none showing any problem. He also has done some acid test for lime also
with no positive results.
He use:
Hawthorn
Gold Art
OM4
Flint
Talc
Red Art
possibly some Custer Spar
Maryland Ref. Grog
Any help would be appreciated Kenneth
LINDA BLOSSOM on fri 13 dec 96
I use Hawthorn Bond and do not have problems. I also am stuck with
Maryland Refractories grog because that is what Laguna carries. According
to Frank Tucker, Maryland Refractories makes their grog from old
firebricks. They don't seem to be careful about where these bricks come
from. It would be nice if Laguna would put their brain in gear and get
Christie Minerals grog which is made fresh. But I don't expect this to
happen anytime soon.
Linda Blossom
2366 Slaterville Rd.
Ithaca, NY 14850
blossom@lightlink.com
http://www.artscape.com
607-539-7912
gshaffer on fri 13 dec 96
Kenneth D Wetfall wrote:
>
> ----------------------------Original message----------------------------
> A fellow clay person called to day to ask if I was have any problem with
> lime pop out coming from Hawthorn Bond fire clay. I presently am using
> A.P. Green fire clay, so I said I would put it out to you all and see if
> any one else mite be having problem. The folks at Cedar Heights told him
> that it was coming from the Maryland refractory Grog. He has sense then
> has mixed grog with some clay from various bags and fired test tile with
> none showing any problem. He also has done some acid test for lime also
> with no positive results.
> He use:
> Hawthorn
> Gold Art
> OM4
> Flint
> Talc
> Red Art
> possibly some Custer Spar
> Maryland Ref. Grog
> Any help would be appreciated Kenneth
Hi Ken,
I got rid of my pop off lime problem by changing over to 50 mesh
hawthorne bonding clay and eliminating grog from my body and have not
had a popoff since. knock on wood.
Gary Shaffer
gshaffer@weir.net
Dana Groemminger on fri 13 dec 96
Kenneth-
I too was having a lot of problems with lime pop outs. In the
last batch of clay I made I substituted AP Green for the Hawthorn and have
had far fewer pop outs. I am deducing that the pop outs I have gotten
since then (with the new batch of clay) are due to the old Hawthorn clay I
recycled into the new batch. I've found that there is a time factor with
the pop outs- some don't "pop" for a few months. A bunch of my pieces
made with the new (AP Green) clay have been sitting in my studion now for
3 months and are showing no signs of the problem. Hope this info helps
your friend- Dana in PA
Frank Tucker on fri 13 dec 96
At 08:53 AM 12/12/96 EST, you wrote:
>----------------------------Original message----------------------------
>A fellow clay person called to day to ask if I was have any problem with
>lime pop out coming from Hawthorn Bond fire clay. I presently am using
>A.P. Green fire clay, so I said I would put it out to you all and see if
>any one else mite be having problem. The folks at Cedar Heights told him
>that it was coming from the Maryland refractory Grog. He has sense then
>has mixed grog with some clay from various bags and fired test tile with
>none showing any problem. He also has done some acid test for lime also
>with no positive results.
>He use:
>Hawthorn
>Gold Art
>OM4
>Flint
>Talc
>Red Art
>possibly some Custer Spar
>Maryland Ref. Grog
>Any help would be appreciated Kenneth
>
Kenneth
I would agree that the lime is from the grog or the hawthorne.Tests are not
much use because lime comes and goes.The only real safeguard is to screen
the clay at 35 mesh or finer.That way , any fine lime that may be left will
not be big enough to cause a pop out.
Frank Tucker
Tucker's Pottery Supplies
Toronto
Dave and Pat Eitel on fri 13 dec 96
>----------------------------Original message----------------------------
>A fellow clay person called to day to ask if I was have any problem with
>lime pop out coming from Hawthorn Bond fire clay. I presently am using
>A.P. Green fire clay, so I said I would put it out to you all and see if
>any one else mite be having problem. The folks at Cedar Heights told him
>that it was coming from the Maryland refractory Grog. He has sense then
>has mixed grog with some clay from various bags and fired test tile with
>none showing any problem. He also has done some acid test for lime also
>with no positive results.
>He use:
>Hawthorn
>Gold Art
>OM4
>Flint
>Talc
>Red Art
>possibly some Custer Spar
>Maryland Ref. Grog
>Any help would be appreciated Kenneth
I've been using Hawthorn Bond in my clay body for about a year and no lime
pops.
Later...Dave
Dave Eitel
Cedar Creek Pottery
Cedarburg, WI
pots@cedarcreekpottery.com
http://www.cedarcreekpottery.com
HWCGmc1@aol.com on sat 14 dec 96
For many years we have used Hawthorn and AP Green fireclays. We screen them
through a 30 mesh sieve before mixing. Screening these clays has elininated
any potential lime problems. Brian at Highwater
Louis Katz on sat 14 dec 96
Lime in fireclays can vary bag to bag. Screens break. Deposits vary.
Mistakes are made. Lime is usually not a problem in stoneware bodies
unless it is bigger than 32 mesh or so. When a screen breaks big stuff
gets through until the break is discovered and fixed.
Louis
***************************************************
*Louis Katz lkatz@falcon.tamucc.edu *
*Texas A&M University Corpus Christi *
*6300 Ocean Drive, Art Department *
*Corpus Christi, Tx 78412 *
*Phone (512) 994-5987 *
**************************************************
Marcia Selsor & Matt Benacquista on sun 15 dec 96
I had lime popping after pieces were in the galleries. I was using
Lincoln Fire Clay. Chip Clausen at Archie Bray Clay Business thought it
was the Lincoln Fire Clay. I don't use Hawthorne. I have switched to AP
Green Fire Clay and don't have problems.
Marcia in Montana
Marci Selsor
Matt Benacquista
http://www.imt.net/~mjbmls/
mjbmls@imt.net
Fran Newquist on sun 15 dec 96
At 09:12 AM 12/14/96 EST, you wrote:
>----------------------------Original message----------------------------
>Lime in fireclays can vary bag to bag. Screens break. Deposits vary.
>Mistakes are made. Lime is usually not a problem in stoneware bodies
>unless it is bigger than 32 mesh or so. When a screen breaks big stuff
>gets through until the break is discovered and fixed.
>Louis
>
>***************************************************
>*Louis Katz lkatz@falcon.tamucc.edu *
>*Texas A&M University Corpus Christi *
>*6300 Ocean Drive, Art Department *
>*Corpus Christi, Tx 78412 *
>*Phone (512) 994-5987 *
>**************************************************
>
Thanks for this explanation. It is a responsible explanation for errors
that might occur in ceramic supply production and does not condemn any
specific company. By the way, I'm looking for some heavy duty grog--as in
chunky for adding to medium and fine for building a kiln. Any suggestions
on how I might contact Maryland Refractories or other grog manufacturers
directly? Thanks in advanc. Fran fnew@erols.com
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