Vince Pitelka on sat 17 jan 98
Autumn Downey from Yellowknife NWT (I always love seeing that - it is
somehow reassuring to know that serious ceramic artists are hard at work and
on-line in Yellowknife, NWT) sent me an email saying that her primary reason
for screening glazes rather than drill-blunging them with a jiffy-mixer was
that in her experience drill-blunged glazes seemed unnaturally thick,
requiring greater additions of water, and then after sitting for a while
they would be too thin. My answer to this is that the drill-mixers, when
improperly used, will suck air and blend it into the glaze, frothing it up
and creating the impression of a thicker glaze. My solution is to have a
variety of sizes of jiffy-mixers, and a variety of sizes/shapes of mixing
containers. For whatever amount of glaze you want to mix, use an
appropriate size/shape container and an appropriate size jiffy-mixer, so
that the impeller is submerged deeply enough to prevent it from sucking air.
Also, if you leave the impeller in one place, it is more likely to create
the "whirlpool" effect and suck air, whereas if you move it around it will not.
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
John Post on sun 18 jan 98
At 09:54 AM 1/17/98 EST, you wrote:
>----------------------------Original message----------------------------
>Autumn Downey from Yellowknife NWT (I always love seeing that - it is
>somehow reassuring to know that serious ceramic artists are hard at work and
>on-line in Yellowknife, NWT) sent me an email saying that her primary reason
>for screening glazes rather than drill-blunging them with a jiffy-mixer was
>that in her experience drill-blunged glazes seemed unnaturally thick,
>requiring greater additions of water, and then after sitting for a while
>they would be too thin. My answer to this is that the drill-mixers, when
>improperly used, will suck air and blend it into the glaze, frothing it up
>and creating the impression of a thicker glaze. My solution is to have a
>variety of sizes of jiffy-mixers, and a variety of sizes/shapes of mixing
>containers. For whatever amount of glaze you want to mix, use an
>appropriate size/shape container and an appropriate size jiffy-mixer, so
>that the impeller is submerged deeply enough to prevent it from sucking air.
>Also, if you leave the impeller in one place, it is more likely to create
>the "whirlpool" effect and suck air, whereas if you move it around it will
not.
>- Vince
Vince,
I agree that keeping the mixing head submersed is important.
I have a method for mixing glazes using the Jiffy mixer. It keeps the
slurry from getting too thick by stirring the glaze frequently while it is
being made.
Most of my ^6 glazes have 15-20% clay in them. For some of the reasons
Tony Hansen has on his web page at
http://digitalfire.com/education/glaze/cone6.htm
Here's what I do,
1. Determine how large a batch of glaze you wish to make. For this
example lets use 8000 grams.
2. Into a 5 gallon bucket I pour 8000 grams of water. You can either
weigh this out or use a container that measures in cc. (1cc = 1 gram of
water). I find that most of my glazes work best with 1 gram of water for
every one gram of dry ingredients.
3. The first dry ingredient I always put in first is the clay (EPK, ball,
etc.). Since my glazes have so much clay in them, I don't use bentonite.
But if I did, I would put that in first.
4. Every time I put an ingredient into the bucket I mix it with the Jiffy
mixer.
5. Add another ingredient. Mix it with the jiffy mixer.
My take on this is that if the clay is supposed to suspend the glaze
ingredients and keep them from settling out, then it's a good idea to get
that into the bucket of water first. By mixing the glaze after I add each
ingredient, I am preventing any big thick lumps of glaze from clumping
together on the bottom of the bucket. Usually when I am done adding all of
the ingredients, the glaze needs very little mixing.
Like Vince I have a variety of Jiffy mixer sizes and use this method with
many different batch sizes. I also have a sieve that fits over the lip of
a 5 gallon bucket and I can just pour the glaze back and forth between two
buckets through the sieve if I really want to get fussy about the mixing.
John Post
jp6mchp@moa.net
Dave Eitel on sun 18 jan 98
Maybe this has already been mentioned, but I've found that sometimes the
jiffy mixer just doesn't break up small clumps of certain materials the way
a sieve does. (Cornish stone is one I've had this experience with, but
there are others.) For some glazes I use both--the jiffy mixer first, then
a Talisman sieve. And I always sieve the ash glazes.
Dave Eitel
Cedar Creek Pottery
Cedarburg, WI USA
http://www.cedarcreekpottery.com
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