Lynne Berman on fri 9 oct 98
You were, as usual, very helpful. It didn't occur to me to ball mill the terra
sig after it settled out. But, I was wrong about not having three layers. Only
a tiny bit of water was visible at the top of the glass jar. However, when I
went to pour the terra sig into evaporating bowls, there was a non-pourable,
thick sludge at the bottom. It just wasn't visibly different looking through
the glass jar.
What I have now is almost 1.15 and we are ready to go. I am still puzzled
about why you start with so much water at the beginning that you have to
evaporate it out at the end. Wouldn't it work with a higher specific gravity
at the beginning? Would the resulting terra sig then have a higher specific
gravity? If so, it would decrease time spent waiting for evaporation.
Vince Pitelka on sun 11 oct 98
>You were, as usual, very helpful. It didn't occur to me to ball mill the terra
>sig after it settled out. But, I was wrong about not having three layers. Only
>a tiny bit of water was visible at the top of the glass jar. However, when I
>went to pour the terra sig into evaporating bowls, there was a non-pourable,
>thick sludge at the bottom. It just wasn't visibly different looking through
>the glass jar.
I am concerned by the use of the term "pour." To get the best terra sig, it
is essential that the settled layers not be disturbed AT ALL. So you need
to siphon off the sig, leaving the thicker sediment behind. There is no
other way to do it that I have found, if you really want the best product.
>What I have now is almost 1.15 and we are ready to go. I am still puzzled
>about why you start with so much water at the beginning that you have to
>evaporate it out at the end. Wouldn't it work with a higher specific gravity
>at the beginning? Would the resulting terra sig then have a higher specific
>gravity? If so, it would decrease time spent waiting for evaporation.
It is important to start off with a 1.2 density in order to get the mixture
to settle out properly. If it is any thicker, the larger particles will not
settle out. If it is thinner, the smaller particles WILL settle out,
leaving nothing but thick sediment and clear liquid. So the ideal
compromise allows the larger particles to settle out, while the smaller ones
remain in suspension, and that is, of course, your terra sig. This ideal
density involves a very delicate balance of three separate forces. First,
you have the forces of gravity dragging particles downwards in proportion to
their actual weight. Second, the deflocculant introduces like electrical
charges to the particles in suspension, causing them to repel one another.
Third, you have the ever-present (except at -273C) atomic vibration, which
tends to cause the smallest particles to be more mobile, as they rebound off
one another. So, the 1.2 density allows the forces of atomic vibration and
electrical repulsion to cause the smallest particles to stay in suspension,
while the forces of gravity still drag the large partcles down. OK?
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Joseph Herbert on tue 13 oct 98
There are a couple of physical things to think about here. First, the big
pieces settle fast and the little pieces settle slow. The further the
distance they go, the farther ahead the big pieces get. Use lots of water and
a tall narrow container. Second, there is no reason to keep the really big
pieces in your container. Once the big pieces have reached the bottom they
can only do harm, so, transfer all the fluid above a certain level to another
container for more settling.
Suppose you had a 3 foot tall tube with a spigot 6 inches above the bottom.
Fill the tube with a very watery clay/water mixture and let settle undisturbed
for a measured time. With another container handy, open the spigot and collect
the entire fluid column above spigot level. Clean your settling tube and pour
your water/clay mixture back into the tube. Settle again for a longer
measured time. Repeat the draining and cleaning.
What this process does is remove the coarser particles from you Terra Sig
creation system. Once they are gone, the way you handle your material becomes
less important because there is no pollutant left. Because geologists are
interested in this kind of thing, there are ways to estimate the largest size
of particle that is left in the fluid column after a certain time. One also
can easily do this by trial and error.
In any event, if you do the described procedure after 15 minutes the first
time and after one hour the second time, the remaining material that
eventually settles will be very fine indeed.
So, let's say that you do this three step process, settle for 15 minutes, then
settle for 1 hour, then settle until the water is clear. You can open the
spigot and drain out all the clear water and your Terra Sig is left in the
bottom 6 inches of the container. This material can be transferred to an
evaporating dish as usual. While this may seem cumbersome, it does eliminate
the possibility of mixing the bad lower layers with your good upper layers.
From a practical point of view, a 36 inch piece of PVC pipe with a cap on the
end makes a nice settling chamber. A valve of some sort can be siliconed into
a hole 6 inches from the bottom. The parts for the whole thing can be
obtained from Home Depot for maybe 10 dollars. It is not necessary to be able
to see through the container. Just drain off your fluid after the proper
time. When you are wondering if the water column is clear, drain a small
amount into a glass container and inspect it.
Ahh, risk-free Terra Sig thanks to technology.