Louis Katz on tue 7 dec 04
You might try hot water. My understanding is that soda fluxed silica is
dissolved pressurized hot water to make sodium silicate. I could easily
be wrong. You might try a little strong acid (HCl or H2SO4) diluted in
the water and if that did not work after careful rinsing to remove the
acid try some lye in hot water. All of this would require some real
safety precautions, rubber gloves eye and face protection, good
ventilation lab apron. Also make sure you know the proper way to dilute
acid. Pouring water into the acid can create powerful reaction sending
up a spray of acid into your face. Read labels. Maybe better to skip
this unless you know how to handle acid safely.
Also I don't know how powerful a reaction between lye and either of the
acids would be, but it would not be kids stuff. I think you should skip
the lye,
1. try the hot water
2. Try glazing it anyways, use some gum in the glaze to get it to stick
over the Sodium silicate.
3. Explain to your son in law.
Also ( I think) sodium silicate does not go into solution easily and it
might be better to set the pots in a tub of hot water that is being
stirred.
My understanding is that high alkali glasses are soluble in mild acids.
I would skip the lye, but high boron glasses dissolve into alkaline
solutions such as lye in water especially when warm.
Ramble Ramble, be careful with acid or lye.
Louis
KE5CVK IRLP node 3499
On Dec 7, 2004, at 3:52 PM, Geoffrey Barst wrote:
> Help! Inadvertently I splashed some sodium silicate onto bisque ware
> and
> the marks are still visible despite immediate rinsing with water. I am
> afraid this will prevent glaze from adhering as well in these areas. Is
> there any way to remove the sodium silicate and will it affect glaze
> adhesion? I wouldn't be so worried for myself but my son-in-law's first
> ever batch of pots was affected and he is going to be devastated if I
> ruined them.
>
> Geoff Barst
>
> _______________________________________________________________________
> _______
> 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.
>
>
Louis Katz
http://www.tamucc.edu/~lkatz
Geoffrey Barst on tue 7 dec 04
Help! Inadvertently I splashed some sodium silicate onto bisque ware and
the marks are still visible despite immediate rinsing with water. I am
afraid this will prevent glaze from adhering as well in these areas. Is
there any way to remove the sodium silicate and will it affect glaze
adhesion? I wouldn't be so worried for myself but my son-in-law's first
ever batch of pots was affected and he is going to be devastated if I
ruined them.
Geoff Barst
mailtoandrew@FSMAIL.NET on tue 7 dec 04
Hi Geoff,
How about refiring the biscuit pieces? Try just one at first to see how it
takes the glaze.
Best of luck,
Andrew
Kruzewski on wed 8 dec 04
mailtoandrew@FSMAIL.NET wrote:
>Hi Geoff,
>
>How about refiring the biscuit pieces? Try just one at first to see how it
>takes the glaze.
>
>
In my experience the sodium silicate doesn't burn off, not even at cone
8, that's why it can make a great "glue" for bisque. Fired to cone 8 it
actually pushed the applied glaze away and where it had done so it
looked like a nasty brown glaze.
Sanding it off does work, it's quick and easy.
Jacqui
North Wales
Tarrant, Derek on wed 8 dec 04
Geoff,
In addition to loss of water, when the pH value of a liquid silicate is
modified to a point below 10.7, the silica is destabilized and the system
polymerizes or gels. Acid conditions won't help remove silicates.
If the article is small enough or you can borrow a preserving pan try
boiling in lye solution. Be aware though that caustic solutions attack
Aluminium and may cause staining.
If you can find one an old STEEL pot or pressure cooker would do a better
job with the same lye solution.
Start with cold water and add about 5% of solid lye to it. It will get hot.
Use an apron, face protection, eyes in particular, plus gloves.
Rinse thoroughly (plus a soak overnight?) afterwards.
Good Luck
Derek
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Louis Katz
Sent: Tuesday, December 07, 2004 10:35 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Sodium silicate on bisque
You might try hot water. My understanding is that soda fluxed silica is
dissolved pressurized hot water to make sodium silicate. I could easily
be wrong. You might try a little strong acid (HCl or H2SO4) diluted in
the water and if that did not work after careful rinsing to remove the
acid try some lye in hot water. All of this would require some real
safety precautions, rubber gloves eye and face protection, good
ventilation lab apron. Also make sure you know the proper way to dilute
acid. Pouring water into the acid can create powerful reaction sending
up a spray of acid into your face. Read labels. Maybe better to skip
this unless you know how to handle acid safely.
Also I don't know how powerful a reaction between lye and either of the
acids would be, but it would not be kids stuff. I think you should skip
the lye,
1. try the hot water
2. Try glazing it anyways, use some gum in the glaze to get it to stick
over the Sodium silicate.
3. Explain to your son in law.
Also ( I think) sodium silicate does not go into solution easily and it
might be better to set the pots in a tub of hot water that is being
stirred.
My understanding is that high alkali glasses are soluble in mild acids.
I would skip the lye, but high boron glasses dissolve into alkaline
solutions such as lye in water especially when warm.
Ramble Ramble, be careful with acid or lye.
Louis
KE5CVK IRLP node 3499
On Dec 7, 2004, at 3:52 PM, Geoffrey Barst wrote:
> Help! Inadvertently I splashed some sodium silicate onto bisque ware
> and
> the marks are still visible despite immediate rinsing with water. I am
> afraid this will prevent glaze from adhering as well in these areas. Is
> there any way to remove the sodium silicate and will it affect glaze
> adhesion? I wouldn't be so worried for myself but my son-in-law's first
> ever batch of pots was affected and he is going to be devastated if I
> ruined them.
>
> Geoff Barst
>
> _______________________________________________________________________
> _______
> 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.
>
>
Louis Katz
http://www.tamucc.edu/~lkatz
____________________________________________________________________________
__
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.
mailtoandrew@FSMAIL.NET on wed 8 dec 04
Hi Jacqui,
Thanks for your observations; I was speaking just from my own experience
when refiring had removed, or at least any detrimental effect, of a number
of splashes that included sod. sil.
As afar as glueing biscuit ... I ve never been convinced myself as all the
examples I ve seen do not bear up to close examination.
It might be worth Geoff deliberately splashing some waste pieces of
biscuit to try the various suggestions before attempting on the actual
pots.
Regards,
Andrew
Kruzewski on wed 8 dec 04
Geoffrey Barst wrote:
>Help! Inadvertently I splashed some sodium silicate onto bisque ware and
>the marks are still visible despite immediate rinsing with water
>
Get some sand paper and sand it off.
I have tested sodium silicate to see if it really would mend bisque -
had a play with a ruined bisque pot. It came in useful when I knocked
off a small but important part of a bisque sculptural piece ( a college
piece that was destined to "live" at home with me). In my experiments I
found that if any sodium silicate is left on the surface after mending
can affect the glaze when the piece is fired, even if the glaze appears
to adhere when it's applied. I found that sanding the sodium silicate
off the surface was successful.
Jacqui
North Wales
Cindy on wed 8 dec 04
Geoff,
The sodium silicate may cause a slightly less absorbent area. I doubt it
will make a big difference. Why don't you try glazing and firing something
you don't care about and see how it works.
Cindy in SD
Kruzewski on wed 8 dec 04
mailtoandrew@FSMAIL.NET wrote:
>Hi Jacqui,
>
>Thanks for your observations; I was speaking just from my own experience
>when refiring had removed, or at least any detrimental effect, of a number
>of splashes that included sod. sil.
>
>As afar as glueing biscuit ... I ve never been convinced myself as all the
>examples I ve seen do not bear up to close examination.
>
>
>
I guess we can only go by our own experiences.
I wouldn't recommend gluing any bisque, especially functional ware, but
the sodium silicate thing came up when Tony Clennell was having trouble
with the footrings of some very large platters. We had a big tub in
college so we just had to play! There were a lot of inexperienced
students spending ages on sculptural work only to have bits fall off in
the bisque. Somehow it seemed mean not to try to mend that work -
especially as they were not ceramics students and this was their only
bash at turning out something in clay.
In the end it solved a bad situation when I knocked off the head of one
of many tiny figures that I had climbing up the side of a large urn -
the biggest pot I had ever made. I had just moved it ready for glazing.
I could have cried! I used sodium silicate plus a paperclay
"elastoplast", sanding paper and a heat gun to get the head back on,
glazed over the lot - and now you wouldn't know it had ever broken. I
was very lucky.
Ordinarily I would swear, chuck the piece away and start again.
Jacqui
North Wales
Ivor and Olive Lewis on thu 9 dec 04
Surely, Sodium Silicate is a strong flux at relatively low
temperatures. The Road Map has it melting at 874=BA C. It is also
recommended as an ingredient in raw Zinc Crystalline Glazes.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
mailtoandrew@FSMAIL.NET on fri 10 dec 04
Hello Ivor,
... =93Surely, Sodium Silicate is a strong flux at relatively low
temperatures. The Road Map has it melting at 874=BA C.=94 ...
Interesting ... I was speaking from my own experience where re-firing had,
seemingly, removed sod. sil. from the pot. I would I hope that Geoff will
share the results of his remedial work, and that others could also advise
of their findings.
Regards,
Andrew
Ivor and Olive Lewis on sat 11 dec 04
Hello again Andrew,
Even if Sodium Silicate (Na2O.2SiO2) melts at 874=BA C it may not
necessarily have a strong solvent action on clay above that
temperature. The effects will be determined by concentration of Sod.
Sil. and the solubility of silica, metakaolinite and perhaps Mullite
from the maturing fabric in the liquid phase
Yes, it will be interesting to read Geoff's conclusions.
I have been considering using Sodium Silicate as an adhesive for
Ceramic Fibre up to 1300=BA. What would be your opinion ?
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Christy Pines on sat 11 dec 04
Ramon Camarillo taught me to use sodium silicate to glue the ceramic
fiber to the inside of my garbage can raku kiln. And Randy Broadnax
paints it on the outsides of pots before shaping them from the inside to
make an amazing textured surface. The pots fire just fine, the clay does
not "melt" from the silicate.
christy in connecticut, having her first sale next weekend. yikes!
cpines at ix..netcom.com
Ivor and Olive Lewis wrote:
>Even if Sodium Silicate (Na2O.2SiO2) melts at 874º C it may not
>necessarily have a strong solvent action on clay above that
>temperature. The effects will be determined by concentration of Sod.
>Sil. and the solubility of silica, metakaolinite and perhaps Mullite
>from the maturing fabric in the liquid phase
>Yes, it will be interesting to read Geoff's conclusions.
>I have been considering using Sodium Silicate as an adhesive for
>Ceramic Fibre up to 1300º. What would be your opinion ?
>
>
>
Geoffrey Barst on mon 20 dec 04
Dear all who weighed in on this topic when I first raised it.
My son in law, whose first ever pots were to be glaze fired and on which I
inadvertently spilled sodium silicate, glazed the pots while I wasn't
there and they have now been fired. I was unable to try any of the methods
suggested in the postings and as far as I can tell there were no ill
effects! Admittedly the areas were small & there wasn't much sodium
silicate involved.
Geoff Barst
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