Farrero, Charley on thu 14 jun 01
I have
been having the most difficult time with plate molds. I have tried four
different slips - a high fire porcelain, M390 (cone 6), M370 (cone 6),
and P300 (cone 6 porcelain). The problem is that the mold dries both
sides of the plate and the pour sprue but when I release the plate, the
clay sticks to both sides of the mold and is still a little wet in the
middle. I have even left the slip in the mold for 24 hours and it still
came apart in two pieces.
The M390, M370 and P300 are dry bagged clay made by Plainsman
(CANADA)and I have mixed it like
this;
Clay 10,000 gms
Water 5,000 gms
Soda Ash 15 gms
Sodium Silicate 15 gms
I mix the soda ash and silicate separately in warm water and then add to
the bucket. I then slake in the dry clay and mix well. I know it is
not supposed to be over 50% water but I haven't been able to do it yet.
I would greatly appreciate any help you could give me.
Thanks
Jae Dean
student Siast campus
C/O farrero@siast.sk.ca
Charley Farrero
farrero@siast.sk.ca
Ceramics dept. WOODLAND CAMPUS
BOX 3003- PRINCE ALBERT.SK.
S6V 6G1 CANADA
ph:(306) 9537064 fax:(306) 9537099
http://www.siast.sk.ca/~woodland/dos/community/ceramic/
studio: Box 145 Meacham S0K 2V0 306-3762221
cfjj@sk.sympatico.ca
http://www.saskterra.sk.ca/profile.htm
http://www3.sk.sympatico.ca/handwave/hcharley.html
Karen Lookenott on thu 14 jun 01
Charley,
This may be a problem with your mold. If the mold has a crusty outside
appearance the problem may be that the plaster is unable to disapate the
moisture in your slip. Take some sand paper and take a small layer of the
outside of the mold off. This will help the mold to take out the moisture.
Also, unless you are pouring this plate to be 100% solid, you could drain
the slip from the plate after it has set up for around 30 Min. Leave the
plate in the mold until you can take it apart, but leave the plate sitting
in the bottom of the mold overnight.
Hope this helps,
Karen
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Farrero, Charley
Sent: Thursday, June 14, 2001 2:07 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Mold and slip Help
I have
been having the most difficult time with plate molds. I have tried four
different slips - a high fire porcelain, M390 (cone 6), M370 (cone 6),
and P300 (cone 6 porcelain). The problem is that the mold dries both
sides of the plate and the pour sprue but when I release the plate, the
clay sticks to both sides of the mold and is still a little wet in the
middle. I have even left the slip in the mold for 24 hours and it still
came apart in two pieces.
The M390, M370 and P300 are dry bagged clay made by Plainsman
(CANADA)and I have mixed it like
this;
Clay 10,000 gms
Water 5,000 gms
Soda Ash 15 gms
Sodium Silicate 15 gms
I mix the soda ash and silicate separately in warm water and then add to
the bucket. I then slake in the dry clay and mix well. I know it is
not supposed to be over 50% water but I haven't been able to do it yet.
I would greatly appreciate any help you could give me.
Thanks
Jae Dean
student Siast campus
C/O farrero@siast.sk.ca
Charley Farrero
farrero@siast.sk.ca
Ceramics dept. WOODLAND CAMPUS
BOX 3003- PRINCE ALBERT.SK.
S6V 6G1 CANADA
ph:(306) 9537064 fax:(306) 9537099
http://www.siast.sk.ca/~woodland/dos/community/ceramic/
studio: Box 145 Meacham S0K 2V0 306-3762221
cfjj@sk.sympatico.ca
http://www.saskterra.sk.ca/profile.htm
http://www3.sk.sympatico.ca/handwave/hcharley.html
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Jonathan Kaplan on fri 15 jun 01
on 6/14/01 12:07 PM, Farrero, Charley at FARRERO@SIAST.SK.CA wrote:
> I have
> been having the most difficult time with plate molds.
You need to find out the correct specific gravity and viscosity of the slip
and adjust it accordingly. Your slip could be over defloc, under-defloc, too
heavy, or too light. You didn't give any indications in your posting.
You also need to pour the slip with care. If the steady stream of slip
impacts the same spot as you pour, the result is a hot spot that will
neither dry correctly nor hold glaze as there is an overly high
concentration of clay material in that spot, as well as being overly wet.
The mold could e at fault also. If it was not mixed at the corret pplaster
consistency (pottery #1 at 70) you can have absorption issues.
Further, before you pout your slip, clean the mold thoroughly and then dunk
it in water quickly. Don't pour a dry mold.
--
Jonathan Kaplan
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
infor@ceramicdesigngroup.net www.ceramicdesigngroup.net
(use PO BOX for all USPS correspondence)
Plant Location
1280 13th Street
Steamboat Springs CO 80487
(use PLANT LOCATION for all UPS, Common Carrier, and Courier deliveries)
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