Kathy McDonald on sun 25 mar 07
Would it be beneficial to add some Epsom salts to my large
containers
of recycle. I presently have about 40 gals of thick slurry
in garbage containers.
It's at the right stage to add stuff and reblunge, before I
move it to pails
for the garage this summer's throwing.
About how much Epsom solution is needed for that amount, and
what concentration
of Epsom to water should the solution be?
The recycle is about 60% Death Valley , 20% BMix and 20%
porcelain throwing bodies
plus about 5% grog at this point.
Kathy
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of
Ron Roy
Sent: Sunday, March 25, 2007 1:12 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Plasticty of Clay Bodies-Dave
Vinegar works but the smell after only a week is not easy to
live with -
and the results are temporary.
I once had to deal with clay with urine in it - never again.
The ideal solution to flocculating clay - and/or
counteracting
deflocculation is Epsom salts in my opinion. It works and
keeps on working.
It works right away and does not interfere with subsequent
beneficial
aging.
RR
>> As I'm sure you are aware plasticity of clay bodies
>> is influenced to some extent by at least these 5
>> factors and there must be others besides these:
>> 1. particle packing
>> 2. moisture content
>> 3. adsorbed organics
>> 4. pH
>> 5. ionic concentration and strength
>
>Dave, regarding number 4. I've heard it recommended that
you can add
>either vinegar or urine to clay to get it to age faster.
Is this
>changing the pH?
>Does anyone have any idea how much vinegar to add to say a
five
>gallon bucket of slurry ?
>I think I'll not try the other option just yet.
>Regards, Lou
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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Paul Herman on sun 25 mar 07
Kathy,
I add epsom salt when mixing new clay or soaking scraps to recycle.
The concentration I use is 10 grams dissolved in one gallon of water.
Not sure that this is the optimum amount, but it works for me. It's
also significant that the water here is a little on the alkaline side.
Best,
Paul Herman
Great Basin Pottery
Doyle, California US
http://greatbasinpottery.com
On Mar 25, 2007, at 11:57 AM, Kathy McDonald wrote:
> Would it be beneficial to add some Epsom salts to my large
> containers
> of recycle. I presently have about 40 gals of thick slurry
> in garbage containers.
> It's at the right stage to add stuff and reblunge, before I
> move it to pails
> for the garage this summer's throwing.
>
> About how much Epsom solution is needed for that amount, and
> what concentration
> of Epsom to water should the solution be?
>
> The recycle is about 60% Death Valley , 20% BMix and 20%
> porcelain throwing bodies
> plus about 5% grog at this point.
>
> Kathy
>
>
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of
> Ron Roy
> Sent: Sunday, March 25, 2007 1:12 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Plasticty of Clay Bodies-Dave
>
>
> Vinegar works but the smell after only a week is not easy to
> live with -
> and the results are temporary.
>
> I once had to deal with clay with urine in it - never again.
>
> The ideal solution to flocculating clay - and/or
> counteracting
> deflocculation is Epsom salts in my opinion. It works and
> keeps on working.
> It works right away and does not interfere with subsequent
> beneficial
> aging.
>
> RR
>
>
>
>>> As I'm sure you are aware plasticity of clay bodies
>>> is influenced to some extent by at least these 5
>>> factors and there must be others besides these:
>>> 1. particle packing
>>> 2. moisture content
>>> 3. adsorbed organics
>>> 4. pH
>>> 5. ionic concentration and strength
>>>
>>
>> Dave, regarding number 4. I've heard it recommended that
>>
> you can add
>
>> either vinegar or urine to clay to get it to age faster.
>>
> Is this
>
>> changing the pH?
>> Does anyone have any idea how much vinegar to add to say a
>>
> five
>
>> gallon bucket of slurry ?
>> I think I'll not try the other option just yet.
>> Regards, Lou
>>
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
>
> ____________________________________________________________
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> melpots@pclink.com.
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> ______________________________________________________________________
> ________
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>
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>
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>
Ron Roy on mon 26 mar 07
Hi Kathy.
The right amount for most situation is 2 lb. of Epsom salts per 1000 lb. of
dry clay. So that is 0.2 lb. per 100 lb. of dry clay.
1 lb. is 453.6 grams - 0.2 of that is about 91 grams per 100 lb. dry clay
Always dissolve in hot water before mixing in.
I don't recommend adding it unless you have a problem with your clay
though. Adding solubles should only be done if there is a good reason to do
so because solubles can cause problems.
Clay in throwable consistency has about 30% water - sounds like your slurry
has a lot more than that. If you mix it up and dry some out after you weigh
it you could find the percent of water - that will get you to how much dry
clay you have so you can calculate the right amount of Epsom to add.
RR
>Would it be beneficial to add some Epsom salts to my large
>containers
>of recycle. I presently have about 40 gals of thick slurry
>in garbage containers.
>It's at the right stage to add stuff and reblunge, before I
>move it to pails
>for the garage this summer's throwing.
>
>About how much Epsom solution is needed for that amount, and
>what concentration
>of Epsom to water should the solution be?
>
>The recycle is about 60% Death Valley , 20% BMix and 20%
>porcelain throwing bodies
>plus about 5% grog at this point.
>
>Kathy
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Paul Herman on tue 27 mar 07
Greetings Ivor,
You must be using a different "gallon" than I am. One gallon here is
not quite four liters, so the concentration is about 0.25 %.
One gallon is enough water for about 25 pounds of dry clay. The clay
being reclaimed has also been treated with epsom salt, so there would
be an increase in concentration, because the dried scraps still
contain epsom salt. I just always use the solution for mixing clay,
new or scrap.
The Frank Hamer quote seems like it must be a misprint. In glazes I
use 0.5 % of the weight of the dry glaze materials. 5 %, yikes!
best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
http://greatbasinpottery.com
On Mar 26, 2007, at 5:48 PM, Ivor and Olive Lewis wrote:
> Dear Paul Herman,
>
> You told us >>I add epsom salt when mixing new clay or soaking
> scraps to recycle. The concentration I use is 10 grams dissolved in
> one gallon of water.<<
>
> This is 10 grams in Five kilograms of water, 10/5000, one part in
> five hundred or 0.2 percent. How much clay does this treat and is
> there a dilution effect from water in the clay which is being
> reclaimed ?
>
> Frank Hamer recommends 5% Magnesium Sulphate for a glaze slop !
>
> It would be interesting to see the chemical equations for the
> reactions that are assumed to occur when you do this.
>
> Best regards,
>
> Ivor Lewis.
> Redhill,
> South Australia.
>
Ivor and Olive Lewis on tue 27 mar 07
Dear Paul Herman,
You told us >>I add epsom salt when mixing new clay or soaking scraps to =
recycle. The concentration I use is 10 grams dissolved in one gallon of =
water.<<
This is 10 grams in Five kilograms of water, 10/5000, one part in five =
hundred or 0.2 percent. How much clay does this treat and is there a =
dilution effect from water in the clay which is being reclaimed ?
Frank Hamer recommends 5% Magnesium Sulphate for a glaze slop !
It would be interesting to see the chemical equations for the reactions =
that are assumed to occur when you do this.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Ivor and Olive Lewis on wed 28 mar 07
Dear Paul Herman,
I think the difference is because I was brought up with the Imperial
system of measure.and I rounded up the fraction.
Which ever way you choose, the value still remains as a small fraction
of one percent.
Your values for mass of clay to volume of water seems to fit well
within the ball park range but it is a far more interesting comparison
if you recast both figures as volumes and in terms of percentages.
These values raise serious questions regarding the water/clay
relationship.
Answers become harder to find if, as in the case of a porcelain,
quartz and felspar, which are not noted for their ability to form a
plastic paste with water, are eliminated from the comparison.
But these are ideas I have voiced before, as the archival record
shows.
Thanks for raising an interesting point. Do you know anything about
the Chemistry between the components of a clay body and Magnesium
Sulphate?
Best regards,
Ivor
Kathy McDonald on wed 28 mar 07
This mixture has always been great so I think
I'll just run with it for another year.
Thanks for the information.
I'll save the email.
Kathy
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of
Ron Roy
Sent: Monday, March 26, 2007 6:48 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Plasticity of Clay Bodies-Dave-question for Ron
R
Hi Kathy.
The right amount for most situation is 2 lb. of Epsom salts
per 1000 lb. of
dry clay. So that is 0.2 lb. per 100 lb. of dry clay.
1 lb. is 453.6 grams - 0.2 of that is about 91 grams per 100
lb. dry clay
Always dissolve in hot water before mixing in.
I don't recommend adding it unless you have a problem with
your clay
though. Adding solubles should only be done if there is a
good reason to do
so because solubles can cause problems.
Clay in throwable consistency has about 30% water - sounds
like your slurry
has a lot more than that. If you mix it up and dry some out
after you weigh
it you could find the percent of water - that will get you
to how much dry
clay you have so you can calculate the right amount of Epsom
to add.
RR
>Would it be beneficial to add some Epsom salts to my large
>containers
>of recycle. I presently have about 40 gals of thick slurry
>in garbage containers.
>It's at the right stage to add stuff and reblunge, before I
>move it to pails
>for the garage this summer's throwing.
>
>About how much Epsom solution is needed for that amount,
and
>what concentration
>of Epsom to water should the solution be?
>
>The recycle is about 60% Death Valley , 20% BMix and 20%
>porcelain throwing bodies
>plus about 5% grog at this point.
>
>Kathy
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
____________________________________________________________
__________________
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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Date: 3/27/2007 4:38 PM
Paul Herman on thu 29 mar 07
>
> Hi Ivor,
>
> I confess to not being a very well informed chemist, but understand
> that epsom salts affect the electrical charge of the individual
> clay platelets, and the way they interact with each other.
>
> Deflocculants cause clay platelets to be attracted to each other
> like this: II
>
> Flocculants cause clay platelets to be attracted to each other like
> this: -I
>
> Am I anywhere in the ballpark?
>
> Best wishes,
>
> Paul Herman
>
> Great Basin Pottery
> Doyle, California US
> http://greatbasinpottery.com
>
>
> On Mar 27, 2007, at 8:30 PM, Ivor and Olive Lewis wrote:
>
>
>> Answers become harder to find if, as in the case of a porcelain,
>> quartz and felspar, which are not noted for their ability to form a
>> plastic paste with water, are eliminated from the comparison.
>> But these are ideas I have voiced before, as the archival record
>> shows.
>> Thanks for raising an interesting point. Do you know anything about
>> the Chemistry between the components of a clay body and Magnesium
>> Sulphate?
>> Best regards,
>> Ivor
>>
>>
>
>
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