Anita M. Swan on sat 1 sep 01
I have seen many references to polishing terra sig with a plastic bag, so I've
tried plastic grocery bags, trash bags and drycleaning bags. None of them have
worked as well as chamois for me. Am I doing something wrong? I've got about 50
pieces to polish by Monday, so I'm looking for an easy way to do this. Any
suggestions? My husband wants to set up some kind of polishing wheel, either on my
bench grinder, drill or dremel. I've been trying to explain that something that
moves that fast might polish right through the pot. Thanks to all! 'Nita
vince pitelka on sat 1 sep 01
> I have seen many references to polishing terra sig with a plastic bag, so
I've
> tried plastic grocery bags, trash bags and drycleaning bags. None of them
have
> worked as well as chamois for me. Am I doing something wrong? I've got
about 50
> pieces to polish by Monday, so I'm looking for an easy way to do this.
Any
> suggestions? My husband wants to set up some kind of polishing wheel,
either on my
> bench grinder, drill or dremel. I've been trying to explain that
something that
> moves that fast might polish right through the pot. Thanks to all! 'Nita
Nita -
In my experience, the plastic grocery bags work best. Apply the terra sig
when the pot is bone dry, in successive layers of very thin sig. Do not do
any polishing until you have built up the desired thickness and surface,
and then wait for the surface moisture to absorb before polishing. You
should be able to get a good glassy shine very quickly with the grocery-bag
plastic. Motorized buffing wheels do not work well for exactly the reason
you cite above.
Please check out my article on terra sig at Tony Hansen's Digitalfire
webpage at www.digitalfire.com/education/glaze/terasig.htm
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Richard G. Ramirez on sun 2 sep 01
Hello all,
Just looking at the post on polishing of terra sig. Has anyone mention
how the plastic is used? I'm assuming, we're polishing on leather-hard and
the plastic is tightly wrapped arount the polishing finger? Using brisk,
slow at times, tiny circular motion to polish? Maybe it was mentionin in
earlier pots and I missed it. But, this is how I polish. Any one else do it
differently? I'm open to diffirent ideas. Thanks "The Clay Stalker"
----- Original Message -----
From: "vince pitelka"
To:
Sent: Saturday, September 01, 2001 4:28 PM
Subject: Re: polishing terra sig
> > I have seen many references to polishing terra sig with a plastic bag,
so
> I've
> > tried plastic grocery bags, trash bags and drycleaning bags. None of
them
> have
> > worked as well as chamois for me. Am I doing something wrong? I've got
> about 50
> > pieces to polish by Monday, so I'm looking for an easy way to do this.
> Any
> > suggestions? My husband wants to set up some kind of polishing wheel,
> either on my
> > bench grinder, drill or dremel. I've been trying to explain that
> something that
> > moves that fast might polish right through the pot. Thanks to all!
'Nita
>
> Nita -
> In my experience, the plastic grocery bags work best. Apply the terra sig
> when the pot is bone dry, in successive layers of very thin sig. Do not
do
> any polishing until you have built up the desired thickness and surface,
> and then wait for the surface moisture to absorb before polishing. You
> should be able to get a good glassy shine very quickly with the
grocery-bag
> plastic. Motorized buffing wheels do not work well for exactly the reason
> you cite above.
>
> Please check out my article on terra sig at Tony Hansen's Digitalfire
> webpage at www.digitalfire.com/education/glaze/terasig.htm
> Best wishes -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Crafts
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Work - wpitelka@tntech.edu
> 615/597-6801 ext. 111, fax 615/597-6803
> http://www.craftcenter.tntech.edu/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
vince pitelka on sun 2 sep 01
> Just looking at the post on polishing of terra sig. Has anyone mention
> how the plastic is used? I'm assuming, we're polishing on leather-hard
and
> the plastic is tightly wrapped arount the polishing finger? Using brisk,
> slow at times, tiny circular motion to polish? Maybe it was mentionin in
> earlier pots and I missed it. But, this is how I polish. Any one else do
it
> differently? I'm open to diffirent ideas. Thanks "The Clay Stalker"
Richard -
One of the reasons I like terra sig so much is that when it is applied in
very thin coats to bone dry wares, it introduces enough moisture for good
polishing. Since the clay beneath is bone dry, all shrinkage has already
taken place. Apply terra sig (no thicker than 1.15 density) in multiple
coats until you build up the surface you want, let the surface moisture soak
in, and then polish with the grocery bag plastic stretched over your
fingertips. In my experience, the kind of polishing movements does not
matter much, as long as you cover the whole surface systematically.
If you polish or burnish at the leather hard stage, the clay will still
undergo some shrinkage as it reaches bone dry. A polished surface will
generally go partially matt due to this shrinkage, and a burnished surface
will go completely matt. Burnishing is really a type of polishing, but as
you probably know it involves compressing the surface with a smooth hard
object, like a shiny stone or the back of a spoon. This compressed surface
has no capacity for shrinkage, and if the piece experiences ANY drying or
firing shrinkage, the burnished surface crinkles on a microscopic level,
making the surface go matt.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
iandol on mon 3 sep 01
Dear Vince Pitelka,
Your reference to leather hard clay reminded me of an early need to =
obtain a mirror finish on "Ammo" boots. Real leather that is. Aside from =
the need for a smooth surface, we used bullock rib bones and a good wax =
polish, we used lots of spit, with a final buffing with silk.
Seems that no one around Adelaide has started to import your book yet! =
Lots of others on the bookshop shelves, but not yours.
All the best,
Ivor Lewis. Redhill, South Australia
vince pitelka on tue 25 sep 01
Recently there was a message from someone commenting on their frustration
trying to polish terra sig with grocery bag plastic. I meant to respond to
it, but now I cannot find the message, so I must have deleted it.
Today I spent the afternoon with my intro class coating sanded pots with
terra sig and then polishing them with pieces of grocery bag plastic. The
results were quite wonderful, and the students were excited about being able
to achieve such a high gloss so easily, especially after I described the
stone-burnishing process.
I have explained this before, but just to clarify, be sure to prepare your
terra sig properly. If you haven't seen it, please check out my article on
terra sig on Tony Hansen's Digitalfire webpage at
www.digitalfire.com/education/glaze/terasig.htm - if you have questions
about it feel free to email me.
When the terra sig is properly prepared and thinned to 1.15 density, you can
apply pretty much as many flowing coats as needed to give you the surface
you want. The only exception to this is with very thin wares, in which case
you should apply a few coats and then let the piece dry before applying more
coats.
After you finish applying the sig, let the pot sit for a few minutes, and
then begin polishing with a large (at least 10" by 10") piece of grocery bag
plastic. Examine the surfaces of the plastic and use the shiniest side, but
avoid using the areas where there are seams or printed words. If there is
any sense of drag as you try to rub the surface, then the piece is still too
damp. Wait a few minutes and try again. If I apply ten coats of sig to a
piece that is 1/4" thick, it is usually ready for polishing about ten to
fifteen minutes after I apply the last coat. Please be aware that this has
entirely to do with the amount of humidity in your environment. If it is
very dry, then the wait might be much shorter, and the opposite if it is a
very humid environment.
If everything has been done as described, you will achieve a shiny surface
very quickly. Hold the plastic sheet flat and use broad unidirectional
back-and-forth rubbing motions with the flats of your hands or fingers. I
have never had this not work, but I keep figuring out ways to make it work
even better.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Ray Gonzalez on wed 26 sep 01
vince,
do you ever have a problem with the terra sig chipping? i have had a
horrible time with this. i have never used true terra sig, as i have always
been too lazy to let the clay settle and siphon off that layer... rather
have used either ball milled OM4 or if i want a more intense, white
background, ball milled EPK. works well. shines right up. pit fires nice,
but over the course of time, i end up repainting aeras. something i am not
horribly in favor of doing.
ray
----- Original Message -----
From: "vince pitelka"
To:
Sent: Tuesday, September 25, 2001 5:44 PM
Subject: Polishing Terra Sig
> Recently there was a message from someone commenting on their frustration
> trying to polish terra sig with grocery bag plastic. I meant to respond
to
> it, but now I cannot find the message, so I must have deleted it.
>
> Today I spent the afternoon with my intro class coating sanded pots with
> terra sig and then polishing them with pieces of grocery bag plastic. The
> results were quite wonderful, and the students were excited about being
able
> to achieve such a high gloss so easily, especially after I described the
> stone-burnishing process.
>
> I have explained this before, but just to clarify, be sure to prepare your
> terra sig properly. If you haven't seen it, please check out my article
on
> terra sig on Tony Hansen's Digitalfire webpage at
> www.digitalfire.com/education/glaze/terasig.htm - if you have questions
> about it feel free to email me.
>
> When the terra sig is properly prepared and thinned to 1.15 density, you
can
> apply pretty much as many flowing coats as needed to give you the surface
> you want. The only exception to this is with very thin wares, in which
case
> you should apply a few coats and then let the piece dry before applying
more
> coats.
>
> After you finish applying the sig, let the pot sit for a few minutes, and
> then begin polishing with a large (at least 10" by 10") piece of grocery
bag
> plastic. Examine the surfaces of the plastic and use the shiniest side,
but
> avoid using the areas where there are seams or printed words. If there is
> any sense of drag as you try to rub the surface, then the piece is still
too
> damp. Wait a few minutes and try again. If I apply ten coats of sig to a
> piece that is 1/4" thick, it is usually ready for polishing about ten to
> fifteen minutes after I apply the last coat. Please be aware that this
has
> entirely to do with the amount of humidity in your environment. If it is
> very dry, then the wait might be much shorter, and the opposite if it is a
> very humid environment.
>
> If everything has been done as described, you will achieve a shiny surface
> very quickly. Hold the plastic sheet flat and use broad unidirectional
> back-and-forth rubbing motions with the flats of your hands or fingers. I
> have never had this not work, but I keep figuring out ways to make it work
> even better.
> Best wishes -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Crafts
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Work - wpitelka@tntech.edu
> 615/597-6801 ext. 111, fax 615/597-6803
> http://www.craftcenter.tntech.edu/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
vince pitelka on thu 27 sep 01
> do you ever have a problem with the terra sig chipping? i have had a
> horrible time with this. i have never used true terra sig, as i have
always
> been too lazy to let the clay settle and siphon off that layer... rather
> have used either ball milled OM4 or if i want a more intense, white
> background, ball milled EPK. works well. shines right up. pit fires
nice,
> but over the course of time, i end up repainting aeras. something i am
not
> horribly in favor of doing.
Ray -
I would expect the problem is most likely in the mixture you are using.
Nothing works as well as a properly prepared terra sig, and the reason it
works so well is because we have isolated the very finest fraction of
particles, and we apply it in repeated thin layers. Are you measuring the
density of your faux-sig? It should be thinned to 1.15 density or thinner
for most applications.
Another factor is the smoothness of the surface on which you are applying
the sig. If the surface is very smooth then the sig has a hard time
sticking. In my ancient clay workshops and my handbuilding classes we
generally sand the forms, and I never have any problem with the sig
chipping. But then, lots of my students use my sig on other forms that have
not been sanded, and they have had very little problems. When they do have
a problem with chipping or peeling it is usually because too many coats were
applied, because it was the bottom of a gallon jar where the sig had
thickened up appreciably, or because someone tried applying the sig to
bisqueware. You can apply sig to bisqueware, but it can only be applied
very thinly, and although I have not done this, I understand that adding a
small amount of 3134 frit will help with adhesion. That's worthy of
experimentation.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
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