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drying rims (was s/crack/drying)

updated fri 20 apr 01

 

Michael Tannock on tue 17 apr 01


Hi Mel
The plaster bat thing sounds like a good idea,

it has taken me a long time to become happy with the shape of the bowls that
I make. There are so many things that happen with the shape during the
drying.

I actually measured the shrinkage in all directions and (as I have heard)
they spring upwards after throwing which changes the proportion alot. I
guess that the amount that this happens will depend on teh style of throwing
etc etc.

But the biggest problem was, with the fine plastic white earthenware that I
use, the thinner rim dries and therefore shrinks quicker and the top 1cm of
the rim bends inward during the drying. It looks really mean. I have
'prevented' this by laying sheets of cling film over the top of the the bowl
after throwing and before lifting off the wheel, but I guess that having an
absorbant bat underneath might help also.

Thanks
Mike Tannock
New Zealand

>while in the japanese studio we would often
>have to use little pancakes of plaster to set our
>thicker bottomed pots on to dry. the water was
>sucked from the thicker bottom as the rim dried.
>
>in many ways, the pot would even out in dryness.
>
>if you are having trouble with drying, try this trick.
>
>
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CINDI ANDERSON on wed 18 apr 01


You can paint wax on the rim when it is leather hard to slow down the dry=
ing.
Cindi

Michael Tannock wrote:

> Hi Mel
> The plaster bat thing sounds like a good idea,
>
> it has taken me a long time to become happy with the shape of the bowls=
that
> I make. There are so many things that happen with the shape during the
> drying.
>
> I actually measured the shrinkage in all directions and (as I have hear=
d)
> they spring upwards after throwing which changes the proportion alot. =
I
> guess that the amount that this happens will depend on teh style of thr=
owing
> etc etc.
>
> But the biggest problem was, with the fine plastic white earthenware th=
at I
> use, the thinner rim dries and therefore shrinks quicker and the top 1c=
m of
> the rim bends inward during the drying. It looks really mean. I have
> 'prevented' this by laying sheets of cling film over the top of the the=
bowl
> after throwing and before lifting off the wheel, but I guess that havin=
g an
> absorbant bat underneath might help also.
>
> Thanks
> Mike Tannock
> New Zealand

Craig Martell on thu 19 apr 01


Hello Michael:

When you lift the bowls off, set them on something absorbent such as gyps=
um
board(drywall) or perhaps a plaster slab. This is what I do and it helps
even the drying especially if the rims are covered a bit. I also throw t=
he
rims down as much as I possibly can instead ot settling them with a rib a=
nd
I drop them a bit further than I want in the finished piece so they will
have a bit of an advantage over the rise upon drying. It's also helpful =
to
not throw the rims too thin and turn off a bit when the bowl is refined a=
nd
finished. I usually pull as much out of the bottom as I possibly can and
leave a bit in the rim and upper part of the bowl. My clay is fairly
plastic porcelain. One body is made with US kaolins and the other body i=
s
grolleg. Both are plasticized with magnesium alumino silicates, macaloid
and vee gum t.

regards, Craig Martell in Oregon