Ian Hodgson on fri 12 sep 97
I'm trying to find out the difference between a throwing body and one
for making casting slip, specifically porcelain. A friend gave me some
good quality porcelain, which is dried out and dirty. I thought I
could use it to make casting slip, but have been told that if it is a
throwing body it will not be any good for casting. Apart from the
deflocculant needed for preparing casting slip, what other material
would I need to add to make it OK? I have been unable to find the
information spelt out in any reference book.
Ian Hodgson
Canberra
ihodgson@agso.gov.au
Eleanora Eden on sun 14 sep 97
Hi Ian and all,
I would look at some slip recipe and make slip from the clay and try it
out. Don't have the formula on the point of my head but a standard amount
of slip should have a certain weight....you get your slurry one way or
another and weigh it and add deflocculant and/or water til the weight is
right. Then you give it a try. If you like the result you take a
hydrometer reading on your slip and then you have a standard to go for. If
you don't want to get so complicated maybe just make a smooth slurry,
custard consistency, about a cup-ful, add a drop or two of deflocculant and
then a bit of water if necessary to give it the consistency of cream and
try it and see.
My recent experiences have called into question the standard lore that the
two are not interchangeable at all. As I mentioned afew days ago I throw
the leftovers of casting all the time. It is easier to use them up that
way than to reclaim them. And for some throwing projects, where the piece
will be cut into and reformed alot, casting slip has its advantages as it
lacks the "memory" that the plastic clays (added for throwability) give a
throwing body.
I don't see why those plastic clays would necessarily ruin a clay for use
as slip, but I can imagine the resulting castings might warp more than
regularly formulated slip if given half a chance.
Eleanora
At 08:07 AM 9/12/97 EDT, you wrote:
>----------------------------Original message----------------------------
> I'm trying to find out the difference between a throwing body and one
> for making casting slip, specifically porcelain. A friend gave me some
> good quality porcelain, which is dried out and dirty. I thought I
> could use it to make casting slip, but have been told that if it is a
> throwing body it will not be any good for casting. Apart from the
> deflocculant needed for preparing casting slip, what other material
> would I need to add to make it OK? I have been unable to find the
> information spelt out in any reference book.
>
> Ian Hodgson
> Canberra
> ihodgson@agso.gov.au
>
>
Eleanora Eden 802 869-2003
Paradise Hill
Bellows Falls, VT 05101 eden@sover.net
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