Russel Fouts, \"Mes Potes et Mes Pots\" on wed 6 oct 99
>> The only disadvantage of this is that you loose all your deflocculant, so
when you reconstitute it with water, be sure to add an appropriate amount of
deflocculant so that the sig will stay in suspension properly. When you
evaporate it in a metal bowl in the kiln, you do not loose any of your
deflocculant, and then you truly have instant sig - only needs water. <<
What's the difference between almost drying and drying out in it's
relationship to how much deflocculant is or isn't removed?
I would think that almost drying it would remove less deflocculant than
drying. It's also true that a "proper" sig will never settle out (Hammer)
since the colloidal particles are so small that the movement of the water
molecules will keep the clay in suspension. My sig, white or orange, will
settle a LITTLE if you leave it alone for several months.
My reduced sig stays in suspension, just fine.
But then you have to remember from my posts of about two years ago that I've
got some weird kind of sig with a specific gravity of about 1.08, almost
water and if you stir it and weigh it again and re-weigh it, it gets even
closer to water. Refer to my paper "Terra-Sigilatta Weighing Rituals,
Lubricants and Libations". Maybe there's some government funding in this.
Mes Potes & Mes Pots
Tel: +32 2 223 02 75
Mobile: +32 476 55 38 75
Vince Pitelka on thu 7 oct 99
>What's the difference between almost drying and drying out in it's
>relationship to how much deflocculant is or isn't removed?
The difference is that you are stiffening your terra sig in a plaster mold,
and the deflocculant, being soluble, is drawn off with the water. I
force-dry mine in a metal bowl, and only the water evaporates leaving the
correct percentage of deflocculant behind with the clay.
The very finest particles will stay in suspension due to atomic vibration,
but why not give them a little more help by having the correct percentage of
When I have the time, I often concentrate my sig by evaporation in large
flat terracotta "evaporating dishes," and I get a high concentration of
deflocculant crystals on the rim and underside of these dishes. I always
add a little more deflocculant when I establish the final specific gravity
of the sig. This has always worked very well for me.
>drying. It's also true that a "proper" sig will never settle out (Hammer)
>since the colloidal particles are so small that the movement of the water
>molecules will keep the clay in suspension. My sig, white or orange, will
>settle a LITTLE if you leave it alone for several months.
Hamer is the authority on so many things, but I question what is meant by a
"proper" sig here. This may be theory rather than practice. Like your
sigs, mine will settle a little if left for a long period of time, but are
easily brought back into suspension with a drill-mixer.
Best wishes -
Home - vpitelka@DeKalb.net
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615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
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Pottery by Dai on thu 7 oct 99
Hello, Russel - I think the difference between evaporating the water off,
and "sucking" the water out through a plaster (or any porous material) mold,
is that when you evaporate, you only take away the water---everything else,
including the deflocculant, stays behind, to magically appear again when
reconstituted. When you "suck" the water out through porous material,
everything that is in the water goes with it. Correct me if I'm wrong,
Vince. This revelation answered a question I was about to post---if I've
thinned a glaze with Darvan, as opposed to more water (which, incidentally,
works like a hot damn!) and accidentally left the lid off the glaze bucket
all night, do I need to add more Darvan with water to get it back to the
right consistency. The answer is no....right?
Dai, working it out in Kelowna, B.C.