Rick Mckinney on sat 8 feb 97
Fellow clayarters,
I seem to remember that there was a message about this a short while back,
but haven't been able to find it. Anyway, is it possible to repair cracks
occurring in greenware? My own crack is in the vertical wall of a slabbuilt
piece - not too big and following along a seam in the building process. I
guess I'm a bit reluctant to throw the piece in the recycle bin. Thanks for
any suggestions I receive. -=Rick=-
Rick McKinney
Department of History 1321 Montclaire Ct.
University of Minnesota and Appleton, WI 54915
mcki0023@gold.tc.umn.edu mcki0023@dataex.com
Tel: 414-830-2226
FAY & RALPH Loewenthal on sun 9 feb 97
Rick we scratch out all along the crack and take vinegar mixed with the clay
and fill it in again. If there is any design obviously you will have to redo it.
good luck Ralph
Paulaclay@aol.com on sun 9 feb 97
Rick, We've talked about this a lot, but here's my secret: Paper clay slip
and vinegar. Your clay body slurry, plus paper pulp (hot water soaked paper,
some people use TP, I like the stronger stuff), and vinegar. Wet the surface
of the crack, apply the goo, cover with a piece of plastic, dry slowly. If
you need further advise, contact me : Paulaclay@AOL.com
The Canal House Studio on tue 11 feb 97
Hi, sorry to be so stupid! but -- is the clay you mix with the vinegar the
clay you scraped out from the crack, or is it clay trimmings, or wet clay or
what?
Margaret Shearman
Merrickville, Ontario
Shauna Mulvihill on tue 11 feb 97
Rick Mckinney wrote:
>
> ----------------------------Original message----------------------------
> Fellow clayarters,
>
.... is it possible to repair cracks occurring in greenware?...
> -=Rick=-
>
> Rick McKinney
> Department of History 1321 Montclaire Ct.
> University of Minnesota and Appleton, WI 54915
> mcki0023@gold.tc.umn.edu mcki0023@dataex.com
> Tel: 414-830-2226
Rick,
First off, I would like to say how happy I am to actually be able to
answer someone's question on clayart. I am a student and I have
recieved dozens of replies to questions I have posted, and I am
extremely happy to contribute in the other direction!
My answer is this: Take a pinch of CMC powder and mix it with some
water to make a mucous like mixture. Add fireclay powder until the
mixture is as close to the claybody you are working with as possible-
alot. You want the mixture to be very plastic and workable. With the
tip of your fettling knife, gently smooth a slight groove over the line
of the crack and tightly fill the crack with the CMC mixture. Let it
dry and fill again until the surface is completely smooth and a crack is
no longer visable.
It works great!
Shauna Mulvihill
Lili Krakowski on wed 12 feb 97
You use any clay you got--I would stay awasy from the one out of the
crack on the off chance that there is some tiny impurity in there that
caused the crack to begin with. I would mush up some dry trimmings. A
friend of mine adds a tiny bit of nylon fiber to the mush. NylonX fiber
has a way of getting into everything but it does a good job for repairs
like this. However it tends to "show" a bit after burning out--surface
not as smooth as might be....
Lili Krakowski lkkrakow@edisto.cofc.edu
On Tue, 11 Feb 1997, The Canal House Studio wrote:
> ----------------------------Original message----------------------------
> Hi, sorry to be so stupid! but -- is the clay you mix with the vinegar the
> clay you scraped out from the crack, or is it clay trimmings, or wet clay or
> what?
>
> Margaret Shearman
> Merrickville, Ontario
>
Talbott on wed 12 feb 97
In the past all of our attempts to do this repair work have proven
to be futile... the crack shows up again (much worse than before) either in
the bisque fire or in the glaze fire... A lot of wasted time and kiln
space...(we fire cone 9/10 stoneware and porcelain). If it is cracked then
recycle the clay while it is still green...Save your clay, kiln space, and
time for something more productive. And that is my 2 cents worth on that!
...... Marshall
1ST ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summmer 1997)
{contact me directly for more information}
Celia & Marshall Talbott
Pottery By Celia
Route 114
P.O. Box 4116
Naples, Maine 04055-4116
(207)693-6100 voice and fax
clupus@ime.net
Live Chat-Room WBS: http://webchat5.wbs.net/webchat3.so
If you want to set up a "Private Room" at anytime in the Webchat
Broadcasting System in regards to the 1st Annual Clayarters' Gallery (or
other ceramic arts discussions) then just use the name: Clayarters
Debby Grant on thu 13 feb 97
Marshall, very well put. I have tried magic mender,Aztec and spooze from
time
to time with limited success. It really isn't worth the time and effort
except perhaps
in an intricate sculptural piece. I also fire at ^9-10. Perhaps it works
better on
low fire ware. I think we should not get so attached to our pieces. Every
failure
is a learning experience and if we made a piece once we should be able to
make
it again. Anyhow, that,s my phiosophy.
Debby Grant
Hiro Matsusaki on fri 14 feb 97
----------------------------------Original
Message---------------------------------
Marshall stated flatly that all attempts to repair cracks in ^9 or 10
stoneware or porcelain are futile. I wholeheartedly and totally agree. I
also noticed many postings which elaborately explained how cracks can
possibly repaired. Here are my observations on this amusing subject.
All of my clay experiences, however short or extensive, attest to the wasted
time, resources, kiln spaces, unfulfilled promises and miracle expectations,
etc. Ordinarily, those who suggest repairs are so convincing that I never
doubted their assertions given to me, sometimes given by unaminous jury
decision. I have yet to encounter a single remedy that has ever worked. I
am partly to blame, since I never faced the jury afterwards to mention face
to face that the decision was wrong. I did not have the heart or courage.
On a rare occasion, my generosity overcame the fear of rejection, and
mentioned the stark naked truth. The unrepaired piece with larger cracks. I
even showed what I thought was a truth or evidence, but they always had some
explanations, like my workmanship. Nifty, isn't it? Hence I wasted a lot of
time, far more than what I could have spent on making a replacement new
piece. Fortunate for the basically lazy person like me, I only tried to fix
large thrown pieces or sculpture. I never bothered small functional pieces.
The truth is that high fire stoneware cannot be repaired. At greenware
stage, that is. Let alone at glazed stage where cracks get larger. If
someone has contrary observations and cures, let us know. Indicate why it
works, etc. There should be a scientific, expensive one. Will be a
tremendous contribution to the entire field.
Certain porcelain bodies can be repaired without using any expensive
materials for some type of chips, cracks, etc., if detected at an early,
greenware stage. If you are an experienced potter, you should be able to
tell when and how. Since I am not, I cannot tell you. Please do not even
e-mail me asking help or advice. It will cost you a bundle, if you try,
anyway, and if I agree to spend time networking. I have too much pleasure
out of these postings, I cannot find time to do other basic things... ...
... Problem is, unless you are an experienced potter, this remedy should
not be attempted. For, shoddy workmanship bordering on tiny cuts, chips or
hairlines (which you can supposedly mend before too late) that you may notice
at the greenware stage will induce cracks, Even sharply cut edge will
initiate a crack. And you only notice the crack after the piece is fired.
The preceding happened when I was learning porcelain from a fourth
generation Danish potter from Copenhagen, whose father belonged to the
reputed Royal Copenhagen or some such prestigeous society. I thought I took
care of the potential problem, and objected to the mentor's admonition and
fired the piece. The cracks developed. Not at the greenware stage. Only
after glaze firing. The greenware looked all right to me. Other repairs I
attempted worked out just fine. So I have a witness. Different from the "LA
type police" planting of this evidence, which exist in abundance, too much,
for which no witnesses exist. If you do not believe me, I am already guilty,
and nothing can convince you the veracity of my statement. Right? Like a
wet handle, it gets worse. My thick porcelain pieces are the living proof.
Experts can tell. So they will meticulously fix the problem areas before
firing, if they are curable. I cannot. If you are new to the field, I
suggest you stay away from high fire porcelian. Once cracked, after any
firing, that's that. There is absolutely nothing you can do to the cracks
for highfire stoneware, as well. And as Marshall implied, this is where
novices often advise the expert. And the so-called expert gets sucked in,
quite easily. We all believe in miracles, and suckers are born every minute
in this overcrowded world.
Big clay sculptures like human bust or head, once a small crack appears after
firing, could be fixed. Since cracks normally appear at the base, since the
time spent to make only a single piece is enormous, and since no one will buy
your masterpiece like that, if all the previous conditions are met, it's O.K.
I have a human head, lifelike masterpiece fired to ^7, brown clay, not
glazed, on my shelf. Everytime I look at it, I can see the inner conflicts
in a modern man sandwitched between old romanaticism and new materialism.
It's supposed to be an Amish bust, using my imaginary Hutterite man. The
greenware on this piece had no cracks, but since it was so thick, heavy, and
fired to a relatively high range, it did. A couple of them. Partly because
I did not pay much attention to the base or the bottom. Just about a couple
of inches. Another a tiny four inch worth (worse). Ugly. The sculpture was
designed to stay unglazed. No more firing. So I could fix it by using the
same clay which had been fired simultaneously, just in case. Crush it and
mix it with any hardner which can make it blend with the fired piece. A good
precaution, as it turned out. I had a good instructor who knew me and the
clay. I don't think I can ever make a piece like that. Hence I have never
tried a new one although I got a commissioned work when I showed it to the
person who committed suicide shortly after. I have never attempted to make
another piece, nor showed it to others, especially to my friends. I am
superstitious, you know. This is genuinely a true story. Life is stranger
than fiction. That sculpture was more than the beginner's luck.
The best greenware crack repairs reside in soft clay workmanship. The time
and resources should be spent there. Do not try to improve your workmanship
repairing the cracks in "high fire stoneware" pieces, which is an almost
impossible task, the phenomena which can be preventable. Repairs on
finished, fired procelain, as you all known, is a different specialty, and if
you are good at it, I'm sure you can make a confortable living out of it.
Alas, it's not befit clayarters. We can ask basic questions, for sure, but
we cannot repair cracks, developing at this forum. (No pun intended. It
turned out this way accidentally, like a crack in a porcelain pot.)
Hiro Matsusaki
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