Janet or Michael Francoeur on thu 2 jul 98
I have been using clear Amaco LG-10 glaze (05). If I put it on a tile so it
is clazed on only one side it fires fine, no bubbles. If I put it on a pot
glazed inside & out I end up with these broken bubbles in the glaze. I have
used this glaze on three different kinds of clay and have the same results,
on tiles ok, on items with glazes on all sides - broken bubbles. Any help
you could give me would be most appreciated.
Thank you so much.
Janet Francoeur
New Bern
Grimmer on fri 3 jul 98
Janet,
You might try bisquing higher, say 04, and a bit slower. Some
clays have lots of carbonaceous matter and other stuff to burn
out and if the bisque is cool or rushed, there may not have
been sufficient time and or heat for this to occur. This can
be a particular problem when using really low temp glazes, as
they can seal over before the out-gassing gets a chance to
finish up in the glaze fire. A clue to this is the fact that
it isn't a problem when you glaze only one side of the
tile--the gasses have an open, unglazed surface to escape
through on the bottom. Glaze a whole pot, and they have no
choice but to push through the melted glaze.
Hope this helps!
steve grimmer
marion illinois
Janet or Michael Francoeur wrote:
>
> ----------------------------Original message----------------------------
> I have been using clear Amaco LG-10 glaze (05). If I put it on a tile so it
> is clazed on only one side it fires fine, no bubbles. If I put it on a pot
> glazed inside & out I end up with these broken bubbles in the glaze. I have
> used this glaze on three different kinds of clay and have the same results,
> on tiles ok, on items with glazes on all sides - broken bubbles. Any help
> you could give me would be most appreciated.
> Thank you so much.
> Janet Francoeur
> New Bern
Clay on fri 3 jul 98
How high you bisque?
I bisque mind to ^ 04 at least. I 'm actually lying.
I bisque to ^ 02 in sitter. , because my kiln is not even . & ....
Well try this first.
Ian Ian
At 09:36 AM 7/2/98 EDT, you wrote:
>----------------------------Original message----------------------------
>I have been using clear Amaco LG-10 glaze (05). If I put it on a tile so it
>is clazed on only one side it fires fine, no bubbles. If I put it on a pot
>glazed inside & out I end up with these broken bubbles in the glaze. I have
>used this glaze on three different kinds of clay and have the same results,
>on tiles ok, on items with glazes on all sides - broken bubbles. Any help
>you could give me would be most appreciated.
>Thank you so much.
>Janet Francoeur
>New Bern
>
Theresa L. Jones on fri 3 jul 98
Janet, I was having similar problems with bubbling. I suddenly started
having bubbling using the same 05 commercial glaze (Mayco series 2000). I
reglazed and refired some pots and after two, or even three, firings the
bubbles went away. I had similar problems with a Duncan 05 glaze (I'm too
lazy to walk out to the studio to look at the name right now but I started
using it over recommended by two potters at a big art festival). I did not
have the problem with flower pots/planters where the inside was not glazed
(just like you). The air could escape through the unglazed side so didn't
have to bubble through the glaze. Sometimes lidded jars did not have the
problems because the air could escape through the unglazed gallery. Bowls
had horrible problems, especially the rims, because the air had to try to
fight it's way through the glaze. The bubbles were definitely concentrated
towards the rim of the bowls.
I never really resolved the problem. Instead, I started doing some cone 6
oxidation and some majolica. I recently did try using the Duncan glaze on a
few pieces, no problems. I am cautiously going to try to start using it
again and start trying to develop a nice clear 05 glaze of my own (favorite
recipes welcome). One potter suggested I put the glaze on thinner which
helped the bubbling, but I didn't like the looks. I even tried using
distilled/rain water for throwing, etc since at that time we were in a
drought (deja vu) and our well was low and water getting very nasty. I
talked to the clay supplier, showed him some of the victims, and he didn't
know why. Some of the advice given me (this was before I hooked into
ClayArt) was to bisque a little higher, glaze fire a little slower, soak,
and glaze fire higher (don't recommend). Anyway, I look forward to what
people have to say because this is a problem I am not over, have just been
avoiding.
>
> ----------------------------Original message----------------------------
> I have been using clear Amaco LG-10 glaze (05). If I put it on a tile so it
> is clazed on only one side it fires fine, no bubbles. If I put it on a pot
> glazed inside & out I end up with these broken bubbles in the glaze. I have
> used this glaze on three different kinds of clay and have the same results,
> on tiles ok, on items with glazes on all sides - broken bubbles. Any help
> you could give me would be most appreciated.
> Thank you so much.
> Janet Francoeur
> New Bern
Theresa L. Jones
tljones@flash.net
Berry Silverman on fri 3 jul 98
Janet,
Clear glazes will react quite differently on horizontal and vertical
surfaces. Are you firing your tiles flat? I am assuming the pieces
you glaze on both sides must be vertical shapes. So that may account
for the difference. I have had occasional problems with broken
bubbles in the past and was able to correct the problem by altering my
firing schedule. I slowed down the firing substantially and I added a
short soak period at the end. You can try refiring the pieces with
bubbles. Just apply a thin layer of clear glaze over the bubbled area
and refire. If you add a soak and slow down the firing, they may heal.
Berry Silverman in Tucson, where it is not fun in the studio at 107
degrees, but at least all the greenware is good and dry.
Janet or Michael Francoeur wrote:
>
> ----------------------------Original
message----------------------------
> I have been using clear Amaco LG-10 glaze (05). If I put it on a
tile so it
> is clazed on only one side it fires fine, no bubbles. If I put it on
a pot
> glazed inside & out I end up with these broken bubbles in the glaze.
I have
> used this glaze on three different kinds of clay and have the same
results,
> on tiles ok, on items with glazes on all sides - broken bubbles. Any
help
> you could give me would be most appreciated.
> Thank you so much.
> Janet Francoeur
> New Bern
>
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Tim Stowell on sat 4 jul 98
I would agree with Berry Silverman's comments. Something to add to them
is, how tight are you packing your kiln. I have found that if there is
not a good 1" - 1 1/2" between the shelves and the rim of a bowl that
there can be problems with bubbles and stuff. The other thing to look for
is were the bubble rings already on the bowl from dipping the
glaze...I've found that it's a good practice to rub the glaze gently with
your smoothing it before firing. Of course this creates dust, so it
should be done with proper dust precautions.
Tim
Tim Stowell Gerard Stowell Pottery
290 River Street
tstwll@juno.com Troy, NY 12180
www.trytroy.org/gerard/
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