Edy Nathan on thu 9 feb 06
Hi All,
I also have a wonderful recipe that calls for barium
and for which I have substituted str. carb, but if I
substitute magnesium, as has been suggested, do I
still need to be cogniznant of the molar basis and how
do I determine the molar basis of one chemical as
compared to another?
If one mole calcium carb is 100 wt units, then what is
magnesium, for example? HOw are these units figured
out? The more I read what many of you speak about on
the list, the more I realize how little I know.
Thanks for the wonderful knowledge that is so
generously shared!
Edy , www.visioninclay.com
--- Ivor and Olive Lewis
wrote:
> Dear Friends,
>
> I suppose the real questions should be, "Why was
> Barium Carbonate incorporated into this Glaze recipe
> in the first place. What unique properties does it
> bring to the quality of the glaze. Is it an Optical
> effect? Is it a Visual effect? Is it a Textural
> Effect?"
>
> The only truly stunning effect I can recall being
> attributable to the inclusion of Barium Carbonate is
> the development of an Opaque Mat Turquoise Blue.
> There may be others but I have not heard about them.
>
> So, why did these recipes incorporate Barium
> Carbonate?
>
> Substitutes. My choice would be Magnesia, either as
> the Carbonate or as Talc. Why pay extra for
> Strontium Carbonate? Lime Magnesia surfaces are
> subtly seductive
>
> Best regards,
>
> Ivor Lewis.
> Redhill,
> South Australia.
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change
> your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be
> reached at melpots@pclink.com.
>
Ron Roy on fri 10 feb 06
Hi Edy,
Remember - you are not dealing with CaCO3 in the molecular formula - you
are dealing with CaO which has a molecular weight of only 56.
The beauty of using the moleculat formula is - the items that leave during
heating (loss on Ignition) - are not counted. So you are looking at the
melted glaze - so solutions are more obvious.
To replace 10 Barium Carb you would use 5 whiting, 7.5 Strontium and to
keep it simple 4 Magnesium Carb.
In each case the expansion of the glaze goes down - with Strontium the
least and with Magnesium the most
The best way to do this is with calculation software - I'll be hapy to help
you do the substitutions if you don't have a program.
Be careful when subbing MgO for BaO - the expansion for MgO is 1/4 the
expansion rate of BaO and if your glaze already has a low expansion rate it
could give fit problems.
A lot depends on how much BaO is in a glaze to start with - the more there
is the harder the probelm is to solve.
RR
>Hi All,
>
>I also have a wonderful recipe that calls for barium
>and for which I have substituted str. carb, but if I
>substitute magnesium, as has been suggested, do I
>still need to be cogniznant of the molar basis and how
>do I determine the molar basis of one chemical as
>compared to another?
>
>If one mole calcium carb is 100 wt units, then what is
>magnesium, for example? HOw are these units figured
>out? The more I read what many of you speak about on
>the list, the more I realize how little I know.
>
>Thanks for the wonderful knowledge that is so
>generously shared!
>
>Edy , www.visioninclay.com
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Steve Slatin on fri 10 feb 06
Edy --
There are two ways to calculate this -- the easy
way is get some glaze calc software and
sub in the new item until your molar concentration
or unity formulas match (do not use weight, or
even molar weight), except for the name of
the melter substituted. This requires no
actual knowledge of math or chemistry.
(Avogadro's number is 6.022 x 10 to the 23rd
power. The ideal gas law is PV = nRT. I have
not had any practical use for these facts in
my entire life.)
The harder (but not actually all that hard) way
is you take the original ingredient and look at
what it is -- say it's (in this case, probably)
barium carbonate, which is BaCO3. The
atomic weights of the various components
(the big number at the bottom of each 'tile'
on a periodic table of the elements) are added
as follows
1 barium at 137.3,
1 carbon at 12.0
3 oxygens at 16.0 each
total mass per single atom of barium -- 197.3
And you want to sub Calcium carb, which is
CaCO3, which totals at
1 Calcium at 40.1
1 Carbon at 12.0
3 oxygens at 16.0
total mass per single atom of calcium -- 100.1
A very good start could be to put in HALF as much
Calcium Carb as the recipe calls for Barium Carb BY
WEIGHT. The glaze will be formed with the same
prevalence of melters as usual, but one melter (calcium)
subs for another (barium). (Could you use 100.1/197.3,
or .507349 instead? Of course! But you don't need to
try to be that precise, and we're only dealing with 3
significant digits anyway, so you shouldn't bother,
and to go from 50.7 percent to 50 percent is a mighty
small difference.)
The reason why this works is that the relative mass
of the different atoms is already expressed in the
periodic table. You don't actually need to learn the
processes to count individual atoms (which, in any
event, gets you working too hard at a fine level of
detail that you then have to round off because the
precision of your weighing methods can't possibly
be as accurate as needed, etc.) so you work in
relative mass instead.
The one thing that everyone needs to pay attention
to is when they're substituting to normalize to a
particular number of atoms in the basic particle --
some molecules have 2 or 3 melter atoms or
whatever, and you want to have the same number,
and not be off by a factor or 2 or 3.
Enjoy your testing, and let us know what your
results are like ...
Best wishes -- Steve Slatin
Edy Nathan wrote:
Hi All,
I also have a wonderful recipe that calls for barium
and for which I have substituted str. carb, but if I
substitute magnesium, as has been suggested, do I
still need to be cogniznant of the molar basis and how
do I determine the molar basis of one chemical as
compared to another?
If one mole calcium carb is 100 wt units, then what is
magnesium, for example? HOw are these units figured
out? The more I read what many of you speak about on
the list, the more I realize how little I know.
Thanks for the wonderful knowledge that is so
generously shared!
Edy , www.visioninclay.com
Steve Slatin --
In watermelon sugar the deeds were done and done again
as my life is done in watermelon sugar.
---------------------------------
Yahoo! Autos. Looking for a sweet ride? Get pricing, reviews, & more on new and used cars.
Daniel Semler on fri 10 feb 06
Hi Edy,
I'm not sure how much strontium carb. you subbed for barium carb - 75% in raw
material terms is usual. The principle is the same either way - do it from
molar equivalents first and work back to weight. My concern with doing
this sub
with magnesium carb. is the affect on expansion. If you have a lot of barium
carb in the recipe the expansion could change a lot. This is of course to say
nothing of the impact on colour.
BTW, how did the strontium carb version turn out ? Was it ok ?
I did a quick calc. on a glaze I have and the proportion appears to be about
43% magnesium carb for barium carb by weight, which is the ratio of their
formula equivalent weights.
Thanx
D
JOYCE LEE on fri 10 feb 06
ok
----- Original Message -----
From: "Ron Roy"
To:
Sent: Friday, February 10, 2006 11:18 AM
Subject: Re: Barium and more questoins
> Hi Edy,
>
> Remember - you are not dealing with CaCO3 in the molecular formula - you
> are dealing with CaO which has a molecular weight of only 56.
>
> The beauty of using the moleculat formula is - the items that leave during
> heating (loss on Ignition) - are not counted. So you are looking at the
> melted glaze - so solutions are more obvious.
>
> To replace 10 Barium Carb you would use 5 whiting, 7.5 Strontium and to
> keep it simple 4 Magnesium Carb.
>
> In each case the expansion of the glaze goes down - with Strontium the
> least and with Magnesium the most
>
> The best way to do this is with calculation software - I'll be hapy to
help
> you do the substitutions if you don't have a program.
> Be careful when subbing MgO for BaO - the expansion for MgO is 1/4 the
> expansion rate of BaO and if your glaze already has a low expansion rate
it
> could give fit problems.
>
> A lot depends on how much BaO is in a glaze to start with - the more there
> is the harder the probelm is to solve.
>
> RR
>
>
>
> >Hi All,
> >
> >I also have a wonderful recipe that calls for barium
> >and for which I have substituted str. carb, but if I
> >substitute magnesium, as has been suggested, do I
> >still need to be cogniznant of the molar basis and how
> >do I determine the molar basis of one chemical as
> >compared to another?
> >
> >If one mole calcium carb is 100 wt units, then what is
> >magnesium, for example? HOw are these units figured
> >out? The more I read what many of you speak about on
> >the list, the more I realize how little I know.
> >
> >Thanks for the wonderful knowledge that is so
> >generously shared!
> >
> >Edy , www.visioninclay.com
>
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Edy Nathan on sun 12 feb 06
Hi All,
Thank you for all of your teachings! The article on
The Mole and for just taking the time to explain this
seemingly very complicated formulation and making it
much more understandable for a layman in the glaze
department!
I will send a copy of the recipe and see what we all
come up with. It should be quite interesting! I now
understand why when I added the same amount of one
chemical to replace another that the glaze did not
come out the same. It makes perfect sense. All of
their base weights are different, their expansion is
different. WOW!
A wonderful door has been opened!
Edy www. visioninclay.com
--- Ron Roy wrote:
> Hi Edy,
>
> Remember - you are not dealing with CaCO3 in the
> molecular formula - you
> are dealing with CaO which has a molecular weight of
> only 56.
>
> The beauty of using the moleculat formula is - the
> items that leave during
> heating (loss on Ignition) - are not counted. So you
> are looking at the
> melted glaze - so solutions are more obvious.
>
> To replace 10 Barium Carb you would use 5 whiting,
> 7.5 Strontium and to
> keep it simple 4 Magnesium Carb.
>
> In each case the expansion of the glaze goes down -
> with Strontium the
> least and with Magnesium the most
>
> The best way to do this is with calculation software
> - I'll be hapy to help
> you do the substitutions if you don't have a
> program.
> Be careful when subbing MgO for BaO - the expansion
> for MgO is 1/4 the
> expansion rate of BaO and if your glaze already has
> a low expansion rate it
> could give fit problems.
>
> A lot depends on how much BaO is in a glaze to start
> with - the more there
> is the harder the probelm is to solve.
>
> RR
>
>
>
> >Hi All,
> >
> >I also have a wonderful recipe that calls for
> barium
> >and for which I have substituted str. carb, but if
> I
> >substitute magnesium, as has been suggested, do I
> >still need to be cogniznant of the molar basis and
> how
> >do I determine the molar basis of one chemical as
> >compared to another?
> >
> >If one mole calcium carb is 100 wt units, then what
> is
> >magnesium, for example? HOw are these units figured
> >out? The more I read what many of you speak about
> on
> >the list, the more I realize how little I know.
> >
> >Thanks for the wonderful knowledge that is so
> >generously shared!
> >
> >Edy , www.visioninclay.com
>
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change
> your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be
> reached at melpots@pclink.com.
>
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