Theresa Sandin on thu 26 jan 06
Hi all!
I have some problems with several of my glazes. I've been away from
pottery for over a year due to an accident, and am now back. My old glazes
are still in their buckets. Some problems remain and some have recently
surfaced. Maybe you guys have some solutions/answers?
My Raspberry does not dry after dipping. It takes up to an hour(!) It used
to be OK, but now it's just outrageous! Does it need de-flocculation, and
if so, how?
A purple and a blue glaze coloured with cobalt carbonate have thickened
beyond belief. The slurry is more like pizza dough than glaze. I suspect
it comes from the carbonate, since those are the only glazes that use it,
and I have one exactly the same glaze only no cobalt carbonate, and it's
OK. Is it so, then why, and can I do anything? I've tried some brown
coffeelike stuff, but then it hardpans, and is still thick as soon as I
stir it.
My glazes crawl. Ol' reliable Variegated Blue only stays on some surfaces
on my mugs! What to do?
I glaze my mugs with a white liner on the inside and coloured glazes on
the outside. I usually dip the mug straight down (bottom down) into the
outside glaze while holding it with my fist inside. This makes the glaze
thick near the bottom and very thin near the rim. What can I do? I've
tried dipping them the other way around, but when I use wax to keep the
rim free of glaze, it does not always go away completely. Do I apply the
wax wrong, or what? Any tips are sooooo welcome!
Theresa
John Hesselberth on thu 26 jan 06
On Jan 26, 2006, at 10:10 AM, Theresa Sandin wrote:
> Hi all!
>
> I have some problems with several of my glazes. I've been away from
> pottery for over a year due to an accident, and am now back. My old
> glazes
> are still in their buckets. Some problems remain and some have
> recently
> surfaced. Maybe you guys have some solutions/answers?
Hi Theresa,
Welcome back. First we need a little more information on your
problem. Glazes that sit for a long time have to be THOROUGHLY
redispersed. And I don't mean just shaking them up or giving them a
stir. Stir them vigorously paying particular attention to the bottom
of the bucket. Then pour them through an 80 mesh sieve--when you do
this you will often find there is still sludge on the bottom of the
bucket--all that sludge has to be scraped out and redispersed. Then
re-sieve them again. Repeat until you have a smooth slurry with no
remaining sludge.
Have you done all that? If so write again and we will try to offer
additional help.
Regards,
John
Belinda Willis on fri 27 jan 06
Theresa wrote:
I usually dip the mug straight down (bottom down) into the outside glaze
while holding it with my fist inside. This makes the glaze thick near the
bottom and very thin near the rim. What can I do?
Theresa,
Before dipping your mugs bottom first, dip the lower one inch or so in
clear water for 2 or 3 seconds. That will wet the bisque ware so it will
absorb less glaze on the bottom.
I slowly lower the mug into the water for about an inch and then slowly
withdraw it, often leaving the very lowest portion in water for even
longer. That way the lowest portion of the wet area is more water saturated
than the upper portion of the wet area and the glaze nicely thins itself
out as it nears the bottom of the mug.
Then after dipping, I rub the bottom of the mug - i.e. the flat part that
rests on the table - on a stiff sponge or on a piece of low pile carpet to
remove any glaze that may be there. That results, after its been fired, in
the loveliest paper thin line of non-glazed clay at the very bottom edge of
the mug. No need to use wax or resist.
Have fun making your mugs!
Belinda Willis
Berkeley, CA
www.greatpottery.com
Judy Rohrbaugh on fri 27 jan 06
Teresa, I have a glaze that I only use to dip the rim of pots, about one inch. Two months can go by without me using it, and it does get thicker, seems to become more soluble-looking. It has copper in it.
I mix this glaze in small amounts. I have found that to just keep rigorously stirring it for what seems forever, then add a tiny bit of water- maybe 1/8 cup or even less, seems to straighten it out. Then I apply it to a test tile, not to fire, but to gauge what it is doing.
Welcome back to pots.
Judy Rohrbaugh
Fine Art Stoneware
Ohio
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