Jamie Yocono on wed 9 may 07
I hope someone here can share a little information about something that I've
been thinking about- controlled slumping. I looked in Hamer's dictionary to
try and find a little information, but it didn't quite give me what I was
looking for.
I'm wondering if there is a way to control slumping, meaning- if I had
something that I purposefully wanted to slump in the kiln, how would I
accomplish that. Conversely, if I'm experiencing slumping, how would I
reduce it? I've been working on some footed vessels, and one of them slumped
in the kiln. I'd like to figure out what made it slump, and then- if I
wanted to, could I accomplish it again?
I understand about clay's memory, so if I have, for example, a rim on a
platter and it slumps down a little while it's drying, even if I nudge it
back into shape, it will do it again while being fired. But what if I WANT
it to slump, how can I determine it's direction and degree of slump?
I appreciate anyone's input. Thanks,
Jamie in Vegas,
www.wooditis.com
Mike on fri 11 may 07
I don't have any idea of what your aiming for, but if you're wadding the
feet, the wads' placement will cause various changes in the shape of the
vessel. Also you can lay the vessel down/at angles to cause it to deform.
One way I can guarantee deformation is trimming thin in one place or
cutting into the clay wall too much. Did this by accident a few times,
and found a water jar shape I really like with the rim slumping, but
held up right and left by the attached lugs. Problem is I haven't been
able to make a new lid to fit yet...
To reduce slumping, try mixing in a more refractory clay to your
claybody, enough to prevent slumping but not so much that you leak like
a seive. This way you can keep your glaze and firing temp the same.
Mike
in Taku, Japan
karatsupots.blogspot.com
potteryofjapan.com
Jamie Yocono wrote:
> I hope someone here can share a little information about something that I've
> been thinking about- controlled slumping. I looked in Hamer's dictionary to
> try and find a little information, but it didn't quite give me what I was
> looking for.
>
> I'm wondering if there is a way to control slumping, meaning- if I had
> something that I purposefully wanted to slump in the kiln, how would I
> accomplish that. Conversely, if I'm experiencing slumping, how would I
> reduce it? I've been working on some footed vessels, and one of them slumped
> in the kiln. I'd like to figure out what made it slump, and then- if I
> wanted to, could I accomplish it again?
>
> I understand about clay's memory, so if I have, for example, a rim on a
> platter and it slumps down a little while it's drying, even if I nudge it
> back into shape, it will do it again while being fired. But what if I WANT
> it to slump, how can I determine it's direction and degree of slump?
>
> I appreciate anyone's input. Thanks,
>
> Jamie in Vegas,
> www.wooditis.com
>
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Ron Roy on fri 11 may 07
Hi Jamie,
Slumping is dependent on the degree of melting of the clay body - if you
want more, fire higher, increase melters, or decrease refractories.
Where clay is thinner you will get more slumping - pots are seldom trimmed
so that the clay is the same thickness everywhere - so you can control it
that way as well.
Then there is the profile of the form - if weight is transferred down in a
gradual way there is less chance for slumping.
Clay - if it reaches the point of pyro plasticity - has to be engineered in
such a way to avoid slumping.
You can certainly break those rules and get slumping.
Having a pot close to an element or burner will increase the chances of
slumping on the side closest to the heat.
Controlling slumping is not going to be an easy thing but I won't say
impossible.
RR
>I'm wondering if there is a way to control slumping, meaning- if I had
>something that I purposefully wanted to slump in the kiln, how would I
>accomplish that. Conversely, if I'm experiencing slumping, how would I
>reduce it? I've been working on some footed vessels, and one of them slumped
>in the kiln. I'd like to figure out what made it slump, and then- if I
>wanted to, could I accomplish it again?
>
>I understand about clay's memory, so if I have, for example, a rim on a
>platter and it slumps down a little while it's drying, even if I nudge it
>back into shape, it will do it again while being fired. But what if I WANT
>it to slump, how can I determine it's direction and degree of slump?
>
>I appreciate anyone's input. Thanks,
>
>Jamie in Vegas,
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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