P. F. Shelor on tue 1 jul 97
I found calcium chloride in building supply stores and garden
supply stores. It is available (cheap) in 50 pound sacks. A
nice guy at the local Southern States co-op gave me a small
bag full out of a broken sack. It came as hard crumbles, kind
of like rock salt, but opaque. I pulverized some in a mortar and
pestle and left it there for a day or two. In the meantime, a
viscous, slightly milky looking liquid formed on top with a small
amount of white precipitate in the bottom of the dish. This
sediment could not be beaten, pried, or coaxed out of the dish.
Figuring it was a salt, and since vinegar is used to dissolve hard
water deposits, I poured some cider vinegar over the concrete
like mass and left it for about ten minutes. Voila - it loosened
its hold and started to dissolve.
Question: This stuff is supposed to prevent a glaze from
turning into a concrete like mass, so why did it turn to a solid
mass on its own? If the pulverized stuff sucks moisture
out of the air and behaves like this, do I want to use it? Is this
an impure form of the chemical or something? Is it supposed
to bind with something else in the glaze mix and behave in a
different manner? Why do the crumbly pellets just sit there and stay
dry?
Here's the glaze recipe:
Extream White ^6 oxidation
20 Whiting
40 Neph Sy.
10 EPK
30 Flint
10 Zirco, Super or Opax.
2 Bentonite
3 Calcium Chloride
Thanks in advance.
Louis Katz on wed 2 jul 97
Calcium Chloride pulls water out of the humid air and then dissolves in
it. If you had placed the mortar in the sink and run water over it it
would have dissolved also.
It takes very little Calcium chloride to flocculate glazes and it is
soluble enough in water that this small amount shouldn't cause a problem.
Calcium chloride is used to melt road ice because it creates it's own
solution at temperatures where salt just sits ontop of ice as crystals.
It also is not as hard on cement as rock salt, although I don't know why.
Calcium Chloride can also be dissolved and sprayed on dust to keep it
down. It does this by pulling water out of the air, it keeps the dust
slightly wet.
Louis
I will be not reading my Clayart Mail for a while unless it says NCECA in
it and my browser filters it in for me. It has been very good to have
filters set up as it allows my Clayart pile from trampling my everyday
email.
Louis
Louis Katz
Texas A&M University Corpus Campus
lkatz@falcon.tamucc.edu
http://www.tamucc.edu/~lkatz
stevemills on wed 2 jul 97
Hi,
Dissolve the CC in warm water till it becomes a saturated solution
and some remains un dissolved. Add to already mixed and balanced glaze
at approx. 1 dessert spoon per UK gallon (8 Imp. pints) stirring as you
go. Cauton : if your glaze contains Bone Ash don't use CC it reacts with
it and sets your glaze like concret!!!
Steve.
In message , "P. F. Sheor" writes
>-----------------------its hold and started to dissolve.
>
>Question: This stuff is supposed to prevent a glaze from
>turning into a concrete like mass, so why did it turn to a solid
>mass on its own? If the pulverized stuff sucks moisture
>out of the air and behaves like this, do I want to use it? Is this
>an impure form of the chemical or something? Is it supposed
>to bind with something else in the glaze mix and behave in a
>different manner? Why do the crumbly pellets just sit there and stay
>dry?
>
>Here's the glaze recipe:
>Extream White ^6 oxidation
>20 Whiting
>40 Neph Sy.
>10 EPK
>30 Flint
>10 Zirco, Super or Opax.
> 2 Bentonite
> 3 Calcium Chloride
>
>Thanks in advance.
>
--
Steve Mills
@Bath Potters Supplies
Dorset Close
Bath
BA2 3RF
UK
Tel:(44) (0)1225 337046
Fax:(44) (0)1225 462712
Tony Hansen on thu 3 jul 97
I think the CaCl is attacking the symptoms rather than the problem.
With 40 NS and only 10 clay any glaze is going to settle and be
very powdery when dry. Why not add some frit so you could reduce
the nepheline and increase the kaolin?
Also the amount of CaCl used here seems incredibly high.
> Question: This stuff is supposed to prevent a glaze from
> turning into a concrete...
> Here's the glaze recipe:
> Extream White ^6 oxidation
> 20 Whiting
> 40 Neph Sy.
> 10 EPK
> 30 Flint
> 10 Zirco, Super or Opax.
> 2 Bentonite
> 3 Calcium Chloride
--
=================================================================
Tony Hansen, IMC thansen@mlc.awinc.com
INSIGHT5/Magic of Fire II demos at www.ceramicsoftware.com
M Richens on tue 8 jul 97
In article <19970630.100116.10798.1.Pammyam@juno.com>, "P. F. Shelor"
writes
>----------------------------Original message----------------------------
>I found calcium chloride in building supply stores and garden
>supply stores. This
>sediment could not be beaten, pried, or coaxed out of the dish.
>Figuring it was a salt, and since vinegar is used to dissolve hard
>water deposits, I poured some cider vinegar over the concrete
>like mass and left it for about ten minutes. Voila - it loosened
>its hold and started to dissolve.
>
>Question: This stuff is supposed to prevent a glaze from
>turning into a concrete like mass, so why did it turn to a solid
>mass on its own? If the pulverized stuff sucks moisture
>out of the air and behaves like this, do I want to use it? Is this
>an impure form of the chemical or something? Is it supposed
>to bind with something else in the glaze mix and behave in a
>different manner? Why do the crumbly pellets just sit there and stay
>dry?
>
>
>Thanks in advance.
Hi,
The Calcium Chloride is quite soluble and as said elsewhere will take
some moisture out of the air. It will also react with CO2 in the air and
form Calcium Carbonate which is chalk. This is relatively insoluble but
react with the organic acid to dissolve.
Max
--
Max Richens max@richens.demon.co.uk +44 (0) 1925756241
Enamel Consultant - Ceramist - Analyst programmer
Software for Batch Formulation and Millroom control.
| |
|
