ivor and olive lewis on sat 9 jun 12
Dear Antoinette,
You ask, "I wonder if it is possible that the platelets may have something
to do with the tiny ridges that fires out at the joints. "
It would be impossible to say with certainty. If you could persuade the
microscopy department of a nearby University to make images with a scanning
electron microscope the images might give a better idea about what is
causing these blemishes.
You could Google Les Blakebrough in Hobart Tasmania and put your questions
to him. Google Les Blakeborough & Southern Ice. He has a web site about
Joining That may give you some clues There should be a contact us url
around somewhere.
Regards,
Ivor Lewis,
REDHILL,
South Australia
Clay art on sun 10 jun 12
Interesting mention Ivor, I put a little vinegar in my throwing water. It
serves several purposes: prevent a sediment in the bottom of my throwing
water. I never throw it out before it becomes too thick and messy to throw
with. It turns my fresh throwing water immediately into a lubricant which
makes throwing porcelain easier. That helps me to throw much thinner before
the clay becomes too soft to throw. I do the final throwing with kidneys.
That dries the pot off right away.
I found the article that you mentioned about joints online, but I really d=
o
not have a problem to join the pieces and if I have cracks, it is not on
joints, but from "rough" handling or over incising. I start working on
walls already 1 or 2 sixteenth inches thick, so I have to be careful and
alert when I work. Also, I let the pots sit until they are ready to trim an=
d
after the trimming when the pieces are quite sturdy, I start a adjusting
process that involves cutting and pasting. Fine timing and precise handling
is of the essence here. So I am really pushing the limits which are the
reason for cracking in my work. Just something to live with. If I do fix a
crack though, it recovers in full, but when I hold it up against light, the
line shows in the wall, like an inner scar, which makes me think the
particle alignment changes.
I thought the ridges may develop because of the deflocculating with vinegar=
.
My reasoning was that casting slip is deflocculated, but I never explored
the reason of slip making ridges at joints; I only know how to prevent the
ridges. It might be worth it to research that, but my logics( I do not have
much...LOL!) tells me it has to do with the particle alignment. That is why
I wonder about the different halloysites.
It seems though as if I will have to live with the ridges or change my ways
since I cannot make that little dent on the joints like one would do with
slip casting, , because I keep building on the form, sometimes 4-5 strips(
sometimes tiny coils or clay balls) until I am satisfied with the form and
smooth it out then. That is when I lose the joints. If it was a matter of
"too wet joints" for the clay, which causes uneven shrinking", the joints
would have been thinner or even cracked, right? Instead it creates a little
ridge.
I hope my rambling is understandable.
Best wishes,
Antoinette Badenhorst
www.porcelainbyAntoinette.com
-----Original Message-----
From: ivor and olive lewis [mailto:iandol@westnet.com.au]
Sent: Sunday, June 10, 2012 2:04 AM
To: Clay art
Subject: Re: A question for porcelain scientists among us
Antoinette,
Reading the site about adding attachments I am in favour of using
Deflocculated Slip rather than wheel head slurry.
A long time ago I discarded the traditional practice of scoring then
brushing wheel head slurry when joining parts. Instead I made and screened =
a
deflocculated slip that had been thickened by evaporation to the consistenc=
y
of double cream. This was placed at the point of joining and the two pieces
were carefully aligned, Accuracy was paramount because the joints set up
instantaneously. some of the joints were well over a metre in length.
Careful control left almost no fettling, not even a wipe with a fine sponge=
.
Hope you solve your problem.
Ivor
----- Original Message -----
From: "Clay art"
To: "'ivor and olive lewis'"
Sent: Sunday, June 10, 2012 3:51 AM
Subject: RE: A question for porcelain scientists among us
> Thank you so much Ivor. It is good to know that I might be on the right
> track.
> Antoinette Badenhorst
> www.porcelainbyAntoinette.com
>
> -----Original Message-----
> From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of ivor and
> olive
> lewis
> Sent: Saturday, June 09, 2012 1:46 AM
> To: Clayart@LSV.CERAMICS.ORG
> Subject: A question for porcelain scientists among us
>
> Dear Antoinette,
>
> You ask, "I wonder if it is possible that the platelets may have somethin=
g
> to do with the tiny ridges that fires out at the joints. "
>
> It would be impossible to say with certainty. If you could persuade the
> microscopy department of a nearby University to make images with a
> scanning
> electron microscope the images might give a better idea about what is
> causing these blemishes.
>
> You could Google Les Blakebrough in Hobart Tasmania and put your question=
s
> to him. Google Les Blakeborough & Southern Ice. He has a web site about
> Joining That may give you some clues There should be a contact us url
> around somewhere.
>
> Regards,
>
> Ivor Lewis,
> REDHILL,
> South Australia
>
>
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