Snail Scott on mon 16 jan 06
At 01:42 PM 1/16/2006 +0000, Gemma R wrote:
>My partners off work and doesnt have much to do, he loves porcelain so i
>brought him a kiln for christmas but were finding very hard to find info on
>how to make porcelain figures?
>
>What is porcelain made out of and where can you buy it ?
>
>Is there any good books on how to make porcelain
>
>and whats the best place to buy paints and material ?
Wow. You need a LOT of information.
To start: If by 'porcelain' you are referring to the sort=20
of figurines one can purchase as 'collectibles', or=20
vintage Dresden-type figurines, or Lladro or souvenirs=20
or things of that sort, these are all made by a ceramic=20
process called 'slip-casting'. It is not terribly=20
difficult, but will require a bit of learning. and some=20
practice. and molds.
Casting slip is a type of liquid clay. It can be made of=20
many types of clay - stoneware, red earthenware (terra=20
cotta), as well as porcelain. It can be made from 'scratch'=20
(from purchased raw materials), but I recommend purchasing=20
it pre-mixed from a local ceramics supply house. If you=20
have none locally, you can probably find one which will=20
ship to you from not too far away. Since porcelain casting=20
slip is used (among other things) for making porcelain=20
doll heads and such, it is often available commercially in=20
a wide range of 'flesh tones' and other colors as well as=20
plain white.=20
Slip-cast objects, whether figurines, pottery, sculpture,=20
or whatever, are all made from plaster molds. Molds are=20
available commercially from many manufacturers and sold=20
through local shops. You can also make your own molds from=20
your own original sculptures.=20
If you choose to make your own molds, this can be a long=20
learning curve, as making molds is a skill of its own,=20
but simple designs can be not too difficult and a great=20
learning experience, and doing your own designs is (I=20
think) much more rewarding than working from someone=20
else's mold design. It's a bit too much to put in one=20
e-mail, but there are many good mold-making books out=20
there. Donald Frith's 'Mold Making for Ceramics' is a=20
good one and very complete, though there are more basic=20
ones as well, which are just fine.
Slip casting basically works by filling the cavity of=20
the plaster mold with the liquid clay (slip), and=20
waiting a short time while the plaster absorbs some of=20
the water from the slip, resulting in a thickened layer=20
against the walls of the mold. The excess slip can then=20
be poured out and saved for re-use. The remaining=20
hollow 'shell' is left in the mold a little longer to=20
dry further, then the mold is opened and the cast object=20
is set aside to finish drying. The mold marks get scraped=20
off and tidied up, and it can then be fired.
Most often, such work is fired once to a low temperature
(1700F=BA-1800F=BA), then glazed (if desired) and refired to=20
a higher temperature. This temperature will depend on =20
what kind of porcelain slip you have chosen, but could
be anywhere from about 2200F=BA-2500F=BA. The glazes you=20
use will also have to be chosen to suit the temperature=20
of your chosen slip. They all have to mature at the same=20
temperature, or it doesn't work too well. (Sometimes,=20
porcelain is fired to the finish temperature without=20
glaze. Unglazed fired clay (of any sort) is what you may=20
have heard called 'bisque'.)
In the US, firing temperatures are most often referred=20
to by what are called 'cones'. There is a good reason=20
for this, but I won't get into that here. Mainly, know=20
that the first 'bisque' firing (as mentioned above) is=20
usually said to be to 'cone 06' or '04' or thereabouts,=20
which corresponds roughly to the temperatures mentioned.
The high firing is usually to either 'cone 6' or to=20
'cone 10', also corresponding to the temperatures=20
mentioned. The important part is this: depending on the=20
type of kiln you bought, it may or may not reach cone=20
10. If not, make sure you get cone 6 slip, and cone=20
six glazes. Also, while there are a (limited) number=20
of cone 6 glazes sold commercially, there are almost no=20
cone 10 glazes available. That's because most commercial=20
glazes are low-fire temperature glazes, which are hard=20
to make at home. To get cone 10 glazes, you pretty much=20
have to make them yourself. If you can cook from a=20
recipe, you can make glazes, but you'll need the raw=20
materials to do it. If you choose cone six, you will=20
be able to buy some glazes, and most kilns can handle it=20
easily. Note that many purists don't consider cone 6=20
porcelain to be 'true' porcelain, and they may be right,=20
but most folks consider that to be splitting hairs. I=20
think you'll be happy with cone 6. It looks and works=20
very much the same.
By the way, the 'O' in the number is really important!
Cone 06 is VERY different from cone 6.
Some shops sell 'greenware' figurines (slip-cast, dry=20
but not fired yet, for you to finish yourself, but most=20
often these are made of a low-temperature (cone 04)=20
whiteware, not porcelain. Other shops of the 'pottery
painting' type sell pre-bisqued shapes to glaze and=20
fire, but these are also usually low-fire whiteware.
I've never seen any that sell porcelain pieces, so=20
these probably won't have what you need.
Another option:
Most porcelain figurines are slip-cast because it's an=20
effective low-tech means of mass production, but if you=20
aren't planning to make lots of them, maybe you could=20
consider sculpting directly in porcelain clay! It=20
works much like any other clay, and can be purchased=20
from ceramics suppliers also (though sometimes not the=20
same ones that sell slip-casting supplies.) You can=20
fire it in your kiln without having to use molds - just=20
make it and fire it! Though it needn't be as thin-
walled as slip-cast work generally is, it WILL need to=20
be hollow inside (solid clay fires badly). Aside from=20
that, just try making and firing some things - it'll=20
be a fun way to try out your new kiln without worrying=20
about getting molds and learning to slip-cast first.=20
(You can still do that, too, of course.) I think it=20
would be fun, but then, I'm biased, since that's what=20
I do for a living! ;)
There's been a quick discussion on this list recently=20
of what books are good for ceramic sculpture. If you=20
weren't a member of the list last week when this topic=20
came up, go ahead and check the Clayart Archives (the=20
web address at the bottom of this e-mail) for the names=20
of those books. Try 'books' as the word to search for,=20
and set the search dates for the last week or so. And=20
get a basic general book on ceramics, too. Whichever=20
technique you end up using, a lot of things are the=20
same for both, like firing, and glazes, etc. Try=20
'Hands in Clay' by Speight and Toki, or 'The Craft and=20
Art of Clay' by Peterson, or Vince Pitelka's book, or=20
any of a number of others.
Check your local phone book under 'ceramics', or maybe=20
'art supplies' for a shop that says 'ceramics'. If=20
you haven't found one, try under 'pottery' and look=20
for a person who is doing ceramics in your area, and=20
ask them where they get supplies. (You can hit them up=20
for other advice later, but start out slow - you don't=20
want to scare 'em all at once!) But get in touch with=20
a supplier who will take time to help you out and make=20
suggestions, and try to find local folks to talk to,=20
too. It's hard to learn everything from a book (or=20
from the Internet).
Tell us where you live - there may be someone on this=20
discussion list who can suggest a source for help.
-Snail
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