Bruce Davis on wed 20 dec 06
I have a Rotozip electric grinder that I just had to have, but then never
could find much use for. I also have the usual bench grinder with the green
grinding wheel that Axner sells. One day I had a bunch pots that had bits of
kiln shelf and other rough stuff stuck to them. I saw an angle attachment for
the Rotozip that included a thin diamond blade about 3" in diameter and only
about 1/16 of an inch thick. That thing slices kiln shelf stuff off with no
problems and the sides of the blade grind all roughness off very
quickly.....naturally you have to use a the usual safety equipment. I am still using
the same blade after two years but a repalcement only costs $17.00.... So, I
feel that this is a good, economical grinder for most pot problems.
Best regards,
Bruce Davis, Mud Run Pottery
Gulfport MS
_http://bdavis6129.blogspot.com/_ (http://bdavis6129.blogspot.com/)
bdavis6129@aol.com
David Berg on wed 20 dec 06
I'm not really understanding the purpose or necessity
of a grinder for the fired pot. Why not just finish the bottom
of the pot at the leather hard state when you are trimming
and cleaning up the bottom. Grinding the fired pot must
make a lot of messy dust.
I trim the base on the wheel, then sponge the bottom and
finally use a blue rubber rib to make the bottom of each
piece very smooth. The only grinding I have to do out of
the glaze kiln is when an occasional piece of kiln wash
sticks and those pieces can usually be picked off with my
finger nail.
David
David Berg
dberg2@comcast.net
http://bergstoneware.com/
Vince Pitelka on wed 20 dec 06
David Berg wrote:
> I'm not really understanding the purpose or necessity
> of a grinder for the fired pot. Why not just finish the bottom
> of the pot at the leather hard state when you are trimming
> and cleaning up the bottom. Grinding the fired pot must
> make a lot of messy dust.
You are certainly right that it makes sense to do as much finishing as
possible at the leather-hard stage. But despite those efforts, the pot
often comes out of the firing with a rough surface due to differential
particle shrinkage, or with residue orf the firing from glaze drips, from
the kiln shelf, or from the firing process itself, as in salt, soda, and
wood firing.
The combination of a grinding wheel and an abrasive flap-wheel mounted on a
bench grinder is the best setup I have found. The grinding wheel is for
glaze drips and other stubborn deposits. The flap-wheel is flexible, and
adjustst to the irregularities of surface, giving a smooth, silky surface
that the customer/user simply loves. When a customer pickes up a
flap-wheel-sanded pot in a craft show or gallery and feels the bottom, it
often brings a smile to their face, because they have all picked up pots
that were rough and abrasive on the bottom, and that is a turn-off no matter
how much one likes the piece otherwise.
This is the shortcoming of a rigid wet-grinding stone for finishing pot
bottoms. It only hits the high spots. It's great for making them sit level
on the table or counter, but if you want that surface that makes the
prospective customer smile, you still need to use the abrasive flap-wheel.
Of course one must accommodate the dust. The bench grinder with flap-wheel
should never be used inside the studio unless you have a very effective
exhaust system mounted around it. It is far better to have it mounted
outside under a shed roof, where you can simply wear a good respirator and
safety glasses while doing your grinding and sanding.
Most of the bargain-priced bench grinders take 6" stones, and you can get
6"x1" flap wheels from www.grainger.com. Be sure to also get the
appropriate bushings to adapt to the shaft size on your bench grinder. If
you find yourself doing a LOT of grinding and sanding on your pots, go for
an 8" bench grinder.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
William & Susan Schran User on wed 20 dec 06
On 12/20/06 9:16 AM, "David Berg" wrote:
> Why not just finish the bottom
> of the pot at the leather hard state when you are trimming
> and cleaning up the bottom. Grinding the fired pot must
> make a lot of messy dust.
Much depends on the clay/process/firing temperature.
I use ^10 B-Mix/Bee-Mix and crystalline glazes.
The process requires grinding/smoothing to finish.
At school students use various ^10 stoneware clays.
Smooth foot with wood/metal/rubber/pastic rib.
No matter the clay, shrinkage will leave grog/rough areas at surface.
Some use Soldate 60 fired to ^10 - leaves very rough surface.
Piece of 320 grit wet/dry sandpaper sufficient to smooth bottoms.
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
| |
|
