Angela Davis on sun 4 apr 04
Ok Hank, thanks for the "plucking" answer,
what is "wet" clay?
I have had this happen with a couple of clays I use,
Macabees, and a white non grogged clay we mix at
school.
Is there something I can do to lessen this effect? I have
learned to be extra careful with how much glaze I leave
at the foot but it doesn't take much at all to cause a problem.
Angela Davis
In sunny Homosassa Fl dreaming of throwing,
"Have joy in everything you make."
----- Original Message -----
From: "Hank Murrow"
To:
Sent: Sunday, April 04, 2004 2:00 AM
Subject: Re: Shelves for the working stiff
> Dear Daniel;
>
> Plucking is when the porcelain pieces stick to the shelf or the wash,
> when you remove them from the shelf. some of the foot stays on the
> shelf. Really only happens with 'wet' clays.
>
> Cheers, Hank
>
> On Apr 3, 2004, at 5:43 PM, daniel wrote:
> >> No plucking,
> >
> > What's 'plucking' ?
>
>
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Snail Scott on sun 4 apr 04
Plucking is most common with clays which become
quite glassy when fired to maturity ('wet') like
porcelains. Kiln wash (preferably a high-alumina
recipe) will usually cure it. The kiln wash can
be applied to the shelf, or to a small 'tile' of
clay (slab or thrown) which each claywork will
sit on top of during firing. For pyroplastic
clays like porcelain, this has the added advantage
of allowing the work to sit on a surface which
shrinks along with it, reducing warping as well
as plucking. To get the warp-resisting advantage,
the tiles must be one-time use, but if your work
is prone to such problems, it's an easy fix.
-Snail
Hank Murrow on sun 4 apr 04
On Apr 4, 2004, at 5:14 AM, Angela Davis wrote:
> Ok Hank, thanks for the "plucking" answer,
> what is "wet" clay?
Dear Angela;
"Wet' clay is clay that is highly fluxed and melty at Cone 10+, which
is my firing point. Because it gets into the glassy phase, it tends to
stick to things. The Alumina oxide acts like little refractory ball
bearings, allowing the foot to shrink and move, and not stick to the
shelf.
> I have had this happen with a couple of clays I use,
> Macabees, and a white non grogged clay we mix at
> school.
> Is there something I can do to lessen this effect? I have
> learned to be extra careful with how much glaze I leave
> at the foot but it doesn't take much at all to cause a problem.
Try mixing some Alumina oxide into your wax, so when you wax your feet,
the drying wax will leave some alumina right where the sticking
(plucking) might occur. I do this on problem clays. Along with the
Alumina on the shelves......the system works.
Cheers, Hank
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