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question about lusters and terra sig.........don't know much

updated fri 8 dec 06


Snail Scott on tue 5 dec 06

about either

At 08:45 AM 12/5/2006 -0600, you wrote:
>about using some lusters at a very low temp over the terra sig to
>basically see what I can get...

Lusters are in the category of finishes
referred to as 'overglazes'. They require
a vitreous surface underneath to develop
their look. On a glaze, they will take on
the same gloss as the glaze underneath -
glossy on glossy, matte on matte, etc. I
happen to like the metallic lusters on
sandblasted surfaces for an even more flat
look. Glaze per se isn't strictly essential,
since any sufficiently vitreous surface
will work: porcelain, for instance, or
glass. Regular bare fired clay won't do it,
though, especially clay fired as low as
terra sigillata.

Ivor Lewis has done some nice work with
lusters on bare porcelain. Joe Bova has done
good work with china paints on porcelain,
too; that's how they put the color on those
old porcelain bisque dolls. It does have to
be a vitreous surface, though. Even well-
vitrified stoneware isn't vitreous enough.
On nonvitreous surfaces, metallic lusters
just turn flat grey. I haven't tested the
nonmetallics like mother-of-pearl luster,
but I suspect that the results would be

Plain clay, even very shiny clay, is still
nonvitreous, and applying lusters to it is
is unlikely to result in anything that
looks like a luster overglaze. That doesn't
mean that whatever you get won't be useful
for something (an expensive way to get matte
grey clay, at least) but it won't look like
an overglaze luster. It probaly won't even
retain the terra sig shine, since the
application of the luster to the surface
will probably disrupt the alignment of the
platelets of clay, and the stickiness of the
luster will prevent reburnishing.

A very low-temperature glaze - low enough to
not compromise the shine of the terra sig -
could be used in those areas where you want
to apply the luster. If this were fired in
the first firing, the luster could be applied
to it and refired to luster temperatures. It
is likely that any glaze of this sort will
show a lot of crazing which will transfer to
the luster. It will also not look quite like
luster laid right onto vitreous clay. Whether
this option might suit your work depends on
your intent.


Vince Pitelka on tue 5 dec 06

about either

> I have a batch of Vince's super refined terra sig that has been
> mixed up and is working quite well (thank you Vince). I'm know thinking
> about using some lusters at a very low temp over the terra sig to
> basically see what I can get. I have never worked with lusters so I
> don't know much about them. My question is, do ya'll think this will
> work? Do you have any recommendations/thoughts on how to go about
> application of the lusters if you do (spraying, dipping, burshing?).
> Also, how unstable are lusters? I have waxed and buffed the TS for a
> nice smooth satin finish. Would this work with the lusters or possibly
> obscure things? I'm happy to experiment here, but don't believe in
> re-inventing the wheel either. Any thougths or suggestions are greatly
> appreciated.

Craig -
Wow, this is a new one on me. I can't wait to hear about the results, and I
mean that. This could be interesting. Generally, lusters work best over an
already-fired glassy glaze, and I am not sure what they will do over a
polished terra sig, but this is certainly worth a try. Obviously, you would
fire your polished terra sig ware, and then apply the luster and refire to
cone 018 or whatever is specified in the luster instructions. I believe
that brushing is the only practical means of application, because the luster
is so expensive and comes in such tiny bottles.

I will be anxiously anticipating the results of your tests.
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111,

Bonnie Staffel on wed 6 dec 06

Sorry, Snail, I have to disagree with your premise. See my previous post.
You apply the terra sig, fire it to Cone 010/ c06 whatever is your wish.
This establishes the terra sig as being part of the pot. You will not lose
the shine. Then apply the lusters, (I have used numerous colors) and then
fire again to the luster cone (018 or such) and you will not get gray. I
then put them in a smoke fire to add to the mystery of the finish. It is a
fascinating way to work. I have heard that you can even torch the lusters
but I have not had any luck with that method.

Regards, Bonnie Staffel
DVD Throwing with Coils and Slabs
DVD Beginning Processes
Charter Member Potters Council

Ivor and Olive Lewis on thu 7 dec 06

Dear Snail,

Thank you for that mention. I would imagine Liquid Gold Lustre will work =
quite well on Terra Sig.

The soft sheen I got from burnished leather hard porcelain is very =
attractive and was well received by my supporters. It avoids the harsh =
metallic glare that comes from applications to high gloss glaze and =
makes full use of the colour of 24kt Gold. Using a sable brush to gave =
good results but never had anything satisfactory an air brush. Were I to =
try again with the air brush I would use a lot of masking because if LGL =
is thin it just gives a pink stain.

Gold leaf can be applied and fluxed to a surface with a Bismuth Lustre. =
Greg Daly is very good at this.

I must do some more of that sort of work

Best regards


Russel Fouts on thu 7 dec 06


>> I'm thinking about using some lusters at a very low temp over the
terra sig to basically see what I can get. I have never worked with
lusters so I don't know much about them. My question is, do ya'll think
this will work? <<

It will definitely work and can look really great. Check out the work of
Geoffrey Wheeldon and Anne James. There are several more that I can
think of but can't remember their names. All are British potters.

Anne James

Duncan Ayscough actually uses gold and silver leaf.

Good luck!