search  current discussion  categories  techniques - terra sigillata 

burnishing, terra sig, and like that

updated sun 23 oct 05

 

Taylor from Rockport on thu 20 oct 05


Howdy Mud Buds:

I figured that Mama Lili has the right idea regarding descriptive phrasing.

I've been asking fellow clayarters off list about my current project and
have gotten great help. Now I come to claytown in toto asking for others'
experices.

I have thrown several pieces with the idea of pit firing them on my
property. I have hole, I have combustibles, and I have barrels. My
choice of moist clays was limited so I have several pieces of heavily
grogged Armadillo raku clay and several pieces of grogged Trinity cone 6
clay. Anybody know what Trinity ^6 lookes like low bisqued?

I realize that many people who pit fire sand their bone dry pieces then
burnish and/or terra sig them. I have taken a page from Watkin's
alternative firing book and burnished some pots using baby oil (mineral
oil with smelly good suff in it), moistening the surface with a damp
sponge, then burnishing. It does fairly well though I do have to rewet
often. My application of baby oil does not help prolong the dampness.
Perhaps those of you who have experience might let me know how it goes
with you. Perhaps a coat of lard, as some do, might be better. Drat, can
vegetabalibarians use lard on their pots and still be card carying members?

On some of the raku clay I have applied some degrogged slip (put those
trimmings to good use) and that does seem to help with the grog marks
somewhat. Still all my burnishing has been done after bone dry and with
the help of mineral oil. I use a spoon.

I'm going to have to try to get a smoother clay body so that I can try
sanding the bone dry ware before burnishing or terra sig application
(still need to make the homemade hydrometer). Right now I'm not so
worried about the grog dimples, but I will want to get that under control
once I settle on a claybody.

How many Clay Town citizens use just burnishing in the pit firing with
good results and how many of you use burnishing and or terra sig for same?

I'm very interested in seeing the results of my testing after I bisque.
I'm shooting for 012 bisque. Any thoughts?

Looks like November before I get pots out into the ground, but it's going
to be fun, folks. If you're a Texas potter, keep your eyes peeled and
calanders open for the first weekend in Feb. I'll try and blog this for
interested parties. Did someone say party?!

3 more day,

Taylor, in Rockport TX

marcia Selsor on thu 20 oct 05


Dear Taylor,
My friend, Manolo Sales, in Spain pit fires and gets copper luster -like
effects on his slab pieces. His pit is about 15" deep and he smolders it
for about 2 days. It gets hotter that barrel sawdust firings.
He leaves some air below the pieces by having a grate support the work.

I use terra sig and then polish with a soft cloth rather than burnish. I
also use salts like copper nitrate, copper sulfate, copper chloride and
table salt, rock salt, in with my combustibles.
Good luck.
marcia selsor

Donna Kat on fri 21 oct 05


We are doing a pit firing this week and it was the first time I ever heard
of using terra sigilatta on bone dry pieces and then buffing with a soft
cloth. I was amazed at how well it worked. A small section of the pot
is 'painted' with the terra sig and after most of the 'wet' is absorbed
just buffed softly. Two or three coats seem to work well (except for where
my cat decided that it was pot licking good). We also used both white and
a peach terra sig in patch work application to give a feel of flashing. I
have mixed feelings about that but I do like the colors. Has anyone else
heard of using Miracle Grow and pressure treated lumber thrown in sawdust
mix for color? I'm a bit learing of this especially if anyone is around to
be inhaling the fumes.


>Dear Taylor,
>My friend, Manolo Sales, in Spain pit fires and gets copper luster -like
>effects on his slab pieces. His pit is about 15" deep and he smolders it
>for about 2 days. It gets hotter that barrel sawdust firings.
>He leaves some air below the pieces by having a grate support the work.
>
>I use terra sig and then polish with a soft cloth rather than burnish. I
>also use salts like copper nitrate, copper sulfate, copper chloride and
>table salt, rock salt, in with my combustibles.
>Good luck.
>marcia selsor

Bruce Girrell on fri 21 oct 05


Donna Kat wrote:

>Has anyone else heard of using ... pressure treated lumber thrown in
sawdust
>mix for color?

Ack!!!!

Pressure treated lumber would, in fact, produce colors, but what a dangerous
way to do it!
Pressure treated wood is also known as CCA lumber, or Chromated Copper
Arsenate.
Chrome
Copper
Arsenic

Colors, yes.
Good idea, no.

Bruce "I use old lace" Girrell

2ley on sat 22 oct 05


From: "Bruce Girrell"

Good point about the pressure treated lumber. Thing is, you *could* use it
in the sawdust, and probably be fine, as long as it was not the only
component, and as long as you made sure to do the firing on a day where
there's at least a slight breeze, and as long as you stayed upwind and
weren't sending the smoke to a neighbor's house, and as long as...

Oh, nevermind. The as long ases are getting as long as my arm.

Philip