Jonathan Kaplan on fri 31 jul 98
We are experiencing some difficulties with RAM pressing a large bowl as follows:
bowl is 14" dia x 5" deep with foot using Laguna Danish White clay
bisque is fine cone 06
glaze to cone 10 R
we are seeing small vertical cracks in the foot
The dies are fine, properly purged, etc. etc. Would appreciate any
suggestions from those on the list who hydraulically press work.
TIA, would be happy to reciprocate
Jonathan
Jonathan Kaplan, president jonathan@csn.net
http://www.sni.net/ceramicdesign/
Ceramic Design Group Ltd./Production Services
PO Box 775112
Steamboat Springs CO 80477
(USPS deliveries only)
Plant Location
1280 13th Street Unit 13
Steamboat Springs CO 80487
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http://digitalfire.com/education/clay/kaplan1.htm
Cameron Harman on sat 1 aug 98
Hi Jonathan,
When I read your post this morning two thoughts came to mind. As
you know any problems, whether its cracks or whatever, in ceramics
can have any on a number of causes. Off the top of my head I can
think of two possiblecauses for your ram pressed ware to have the
cracks you mentioned.
They could always be drying cracks, but if these pieces crack
right off the ram press, then it is a flowing problem. I have run
into this problem many times before and it ususally occurs when
there is not quite enough plastity in the mix. This can be changed
by adjustng the amount of water usually only a 1/2% or so more.
Other times it is corrected by adding a small amount of organic
binder such as corn flour to increase the "slippage" of the mix.
I know that there may be other things that are not so hard to
arrange, but these two came to mind quickly.
best of luck,Cameron
--
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Cameron G. Harman, Jr. 215-245-4040 fax 215-638-1812
e-mail kilns@kilnman.com
Ceramic Services, Inc 1060 Park Ave. Bensalem, PA 19020
see our web site at http://www.kilnman.com
THE place for total kiln and drier support
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