May Luk on fri 18 feb 05
Hi all;
I've been experimenting slip trailing with porcelain slip on porcelain. The
porcelain slip is left over from throwing. I found the 'trail' a bit flat
and not puffy like I envision it to be. I had taken off some water and it
got a bit better. I wonder if this is just how porcelain is supposed to be.
I had read the recent epsom salt thread. I wonder if the epsom salt would
thicken the slip and make a thicker application or the effect is merely
superficial.
T.I.A.
May
London, UK
John Britt on fri 18 feb 05
May,
To get the thickened slip like you want, you need to deflocculate the slip
and then thicken it.
To do this you take your wet slip from throwing water and mix well, then
remove the excess water. Then add a teaspoon of deflocculant or so,
depanding on how much you have, (Darvan 7, 211, sodium silicate, etc.).
Then have some dried trimming scraps of your body all crunched up or
powdered. When you add the defolcculant, the slip will become very
watery, you then add the dried/powdered scraps until it thickens.
This reduces the amount of water (which equals shrinkage) to clay and
allows the slip to keep its relief when dried.
Hope it helps,
John Britt
www.johnbrittpottery.com
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