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casting slip from dry throwing trimmings

updated wed 7 dec 11

 

jonathan byler on mon 5 dec 11


we make our casting slip so that the specific gravity is about 1.8.
that means that the slip weighs 1.8x more than an equal volume of
water. about 50 grams of sodium silicate was usually about right to
deflocculate, but this might not be the case for your particular
claybody.

our recipe calls for about 25lbs of dry ingredients and close to 12lbs
of water. makes about 2/3 of a 5 gallon bucket. add less than the
full volume of water (say 10 lbs.) mixed with the sodium silicate.
then add water to make the specific gravity reading correct. when
measuring the specific gravity, make sure you are really using an
equal full measure and make sure there is no slip gooped to the sides
that would throw off your measurements. I like a cut off plastic
water bottle for this, but you could using measuring cups, whatever.
just fill it to the very top. in a glass measuring cup the slip is
too thick to read the lines with any serious accuracy.

this works for us with a whiteware/porcelain body that fires to ^10.
not sure what type of claybody you have so YMMV.

-jon


On Dec 5, 2011, at 10:11 PM, Ashburn Pottery wrote:

> Help - I need to make a few gallons of casting slip using dry
> trimmings from
> our
> throwing clay. I know I need to add sodium silicate as well as
> water but
> could use some help regarding the amounts.
> I have liquid sodium silicate.
> John Bandurchin
> Baltimore Ontario Canada

Ashburn Pottery on mon 5 dec 11


Help - I need to make a few gallons of casting slip using dry trimmings fro=
m
our
throwing clay. I know I need to add sodium silicate as well as water but
could use some help regarding the amounts.
I have liquid sodium silicate.
John Bandurchin
Baltimore Ontario Canada