bill edwards on wed 21 sep 05
This is an alginate found in kelps and wracks largely
coming from brown algae/seaweeds. Some are as high as
30-40% by weight others lower. This is a viscous
material that forms a hard shell when used with
glazes, paints or other materials as well as works
similar to CMC or carboxymethyl cellulose. Alginates
have been used to take up heavy metals in certain
conditions such as lead. Both of these compounds as
well as Guar gums are used in foods and especially the
textiles market.
The potter there must have understood the good use of
kelp or sea-weed that lived next to the banks in some
places and was able to reduce it by extraction and
making proper use of it. When I was in Maine I used to
collect a little of it from the brackish waters near
the mouth of the Ocean just so I could squish it
around and gum up my hands to pass the time. Was more
fun washing it off in un-salted water.
Extraction - My theory, would be cold press extraction
with heat at the end. It combines with calcium ions
and is thermally stable or heat treated without
melting. Alginates hold water and are pH dependent in
my experience. They will show high water absorption,
used in low viscosity emulsifiers and shear thinning
thickeners. Also in a glaze based on pH it can spoil
and start stinking just like CMC. It often has its own
smell that you will become accustomed to and never
forget. Not a bad one, just different! I used sodium
alginates, CMC's and other commercial thickeners to
include acid reactive, my favorite of all time for
buttery short rheaology for sprayability. Long stringy
rheaology of gels is often better in brushed paints.
Use CMC if you can't find a alginate or try making
your own from brown seaweed and cold pressing it and
then heating the solution to make a gel or thicken the
gel. Wash you bladder-wrack well! Lol
At one point and many years ago I spoke about this on
here and the use of shear mixing equipment. I made the
claim of not using any screening methods or ball
milling which opened up a large discussion because
most people don't know what shear mixing is and how it
is done but no one personally got back to me with
their results except for a mention from one other
chemically exicited potter. Just so everyone knows -
It's just a high speed mixer with a special head on it
that shears or tears through whatever compound you put
in there like paper pulp for example or hard clay. I
made my own paper back then too. Cowles induction
mixing and homoginization mixers are complicated and
highly expensive. If you want to mix in a similar
fashion go buy you a hand held drink mixer for about
12.00 bucks at Target thats used to crush ice and
discard it once the bearings goes to rubbing and
making a noise. This is great for 1 gallon mixes or
less because it can totally dissolve the solution
enough not to have to filter, screen or pull your hair
out over and you will know by looking if you have your
glaze thick enough or not. I have never screened any
glazes in my life with exception to working at another
studio where they used boat paddles and window screens
for everthing with an occasional screen of 100 mesh
for that special occasion. Of course they were afraid
to let me make their glazes in the beginning because I
might mess up their scientific approach. They're doing
much better these days.
(Do 'READ' this)
Unless your making glazes from rock, you seldom need
to ball mill if you can use enough shear force mixing.
Wollastonite after aging benefits from this source of
mixing IMHO. This is achieved easily by the above
mention unless you are trying to achieve another goal.
(for another discussion) Like some of the other stuff
I have offered and never heard a word back on, try it.
(Perhaps I need not give my experiences out any
longer, it doesn't merit anyone when nothing is said
or done with it)It becomes perplexing only when you
work very hard to get information out and you seldom
if ever hear much back in return and thats a small
expectation in my view. The reality is; I have those
who have asked for things but will not even tell me
how they worked. I research, I like to know more and
do better by inclusion not exclusion of
information/people as often as I can. I know I have
missed the popularity boat by being frank and honest
and forward at times but the values of science and
chemistry are still viable and good and experimentally
challenging enough to want to try changing some ways
on occasion and thinking outside the bun. What have
you to lose? (do not pull air in when you are mixing,
keep the mixer below the fluid line and your fingers
out from the bottom of the mixer) You might even gain
from the exercise. It's free information and some of
this will be discussed in more greater detail in
chapter 6 of the book I am working on. I am still not
sure I will publically ever release the book but it
will be available when I do work shops and shows here
and there. So no, I am not hawking a thing in reality.
Just exploring more territory and defining if I need
to continue or just go it alone and stop worrying
about other things. I could be more productive I am
sure,for myself! Actually I was given a good lecture
by one of the stores owners I do business with. She
was honest, told me to slow down and be an artist.
Thats why I got out of the business I was in. I just
wanted to be an artist. I came out with information,
you have information I could use. We are all bright
people, some of us just don't exercise enough and
challenge ourselves effectiviely at times. John Post
gave me the best work-out I have had in 3 years
almost. I am indebted to him, and Ron was able to
scratch an itch enough to make me want to explore a
little at a time when I didn't have the time. And I
thank you greatly! Dr. Ed has become invaluable to me
as a friend and a great source for toxicology
understanding in out craft. Please, listen to him. You
can always argue merits and check the facts on your
own accord if you need to define your critical points
better down the road.
(Mel San)
seaweed gel that is made for potters in
japan is not just nori glop.
i have no idea what the recipe is:
uchida used it both in slip and glazes.
Bill Edwards
Edmar Studio and Gallery
302 South Main St (Shipping)
POB 367 (Mailing)
Camp Hill, Al. 36850
http://apottersmark.blogspot.com/
Katrina Evacuee's BLOG
http://katrinaopelika.blogspot.com/
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