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having cracking problems

updated sat 24 feb 07

 

Bunny Lemak on fri 23 feb 07


Yesterday I made a few hump/slump pieces and when they were leather hard I
took them off the mold and put on to a piece of plaster board, covered
with plastic to dry. Do this all the time without any problems.

Checked on them this morning and 2 pieces have hairline cracks. Ok, no
problem wet it down, put some slip in the cracks, covered and checked on a
few hours later......still the same cracks showed up! Repeated the same
process, and once again a few hours later, there they are again!

I have done this process many a time without any problems, so what is
wrong now??

I know the pieces are cracking, I think I am cracking up too! Help!!

How do you correct/fix cracks in leather hard clay????

Bunny
Yesterday it was mid 70's, today it is cold & rainy - go figure!

Craig Clark on fri 23 feb 07


Bunny, I have never tried to fix cracks in leather hard clay. I wait
until the clay is completely dry and then if the piece was labor
intensive enough to warrant a repair, I will then apply one of several
of the wonderous fixes. Take your pick: there is Lana's Magic water,
there is the slip you make from your clay body with the addition of a
little bit of vinegar (to taste), there is my favorite and the one I
have had the most luck with.....paper clay slip-aka P-slip- which is
truly magic among other choices.
If these cracks are suddenly showing up and you have not changed
your procedure then you may take a look at the clay body itself.
Something could have changed there. Before looking beyond your basic
procedure make certain that everything is the same as usual along with
atmospheric conditions, the amount of time you leave the pieces in the
molds, and whether or not the cracking is common to both the slump and
the hump molds.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
http://mudman00.blogspot.com/


Bunny Lemak wrote:
> Yesterday I made a few hump/slump pieces and when they were leather hard I
> took them off the mold and put on to a piece of plaster board, covered
> with plastic to dry. Do this all the time without any problems.
>
> Checked on them this morning and 2 pieces have hairline cracks. Ok, no
> problem wet it down, put some slip in the cracks, covered and checked on a
> few hours later......still the same cracks showed up! Repeated the same
> process, and once again a few hours later, there they are again!
>
> I have done this process many a time without any problems, so what is
> wrong now??
>
> I know the pieces are cracking, I think I am cracking up too! Help!!
>
> How do you correct/fix cracks in leather hard clay????
>
> Bunny
> Yesterday it was mid 70's, today it is cold & rainy - go figure!
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
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>

Richard Walker on fri 23 feb 07


Bunny,

Interesting, from the perspective that I have had exactly the same thing happen. The only difference in what you are describing and what I do is that I seldom cover the piece with plastic and they dry just fine with no cracking at all. Then that one time comes along and a hair line crack appears. Weeks and month's may go by and not another problem, then it happens again. I haven't a clue why other than the clay gods are playing tricks or there was a sudden change in atmospheric pressure. Hope you get an answer. I'll be watching.

Dick


>From: Bunny Lemak
>Date: 2007/02/23 Fri PM 04:17:39 CST
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Having cracking problems

>Yesterday I made a few hump/slump pieces and when they were leather hard I
>took them off the mold and put on to a piece of plaster board, covered
>with plastic to dry. Do this all the time without any problems.
>
>Checked on them this morning and 2 pieces have hairline cracks. Ok, no
>problem wet it down, put some slip in the cracks, covered and checked on a
>few hours later......still the same cracks showed up! Repeated the same
>process, and once again a few hours later, there they are again!
>
>I have done this process many a time without any problems, so what is
>wrong now??
>
>I know the pieces are cracking, I think I am cracking up too! Help!!
>
>How do you correct/fix cracks in leather hard clay????
>
>Bunny
>Yesterday it was mid 70's, today it is cold & rainy - go figure!
>
>______________________________________________________________________________
>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.