Louis Katz on tue 30 nov 04
I often resort to thicker wash, and unless my students get seriously in
trouble with a glaze or use my ash glaze get mixed up with some rakuish
nightmare or something equally dangerous I don't have much of a
problem. I put fine fairly pure silica sand in my glaze which allows me
to easily buildup a thicker coat. It also seems to patch well. Keep you
glazes at a consistency where over thick clay they need two coats to be
"thick" . Make sure your lazes have some bentonite which seems to
inhibit real thick pots from picking up much more glaze than thin ones.
people may shiver when I suggest this, but I am still using ten year
old Thorley's in my reduction kiln. I will need some replacements
sometime soon but:
After I chip off the worst of a glaze and put a bit of time into hand
grinding, I then paint a heavy coat of wash over the glaze. On new
shelves that are flat and beautiful I grind more but.....
Also if you use glazes that are more related to each other in
ingredients you don't get as many glazes that in combination with each
other run like crazy.
Make sure you tell them about combinations being more likely to let
loose than individual glazes.
Good luck.
Louis
On Nov 30, 2004, at 5:02 PM, Claire Reishman wrote:
> Hello Potters. I teach at St. Andrew's-Sewanee School in Tennessee,
> and we
> have both Bailey gas reduction kiln and a hand-built soda/salt kiln.
> I have
> two firing questions:
>
> 1) despite our most intense instruction, our students are not
> always
> very good about glazing pieces properly, and we often have running in
> both
> of our kilns from glazes which were applied too thickly. We try to
> grind
> off the runs with an electric hand-held grinder, and we've used a
> grinding
> wheel for metal and steel, and a grinding wheel for concrete. Both
> wheels
> wear down very quickly, we've found. My colleague and I recognize
> that the
> ultimate solution to this problem lies in teaching the students better
> about
> glazing, and eliminating the dripping. However, we have a group of
> shelves
> from our first firings of the year that have some serious glaze drips
> on
> them. Does anybody have a recommendation for a grinding tool which we
> could
> use on our shelves to remove glaze problems?
>
> 2) we use both soda and salt in our soda/salt kiln when
> firing, and
> we spray the soda/water solution in using a garden sprayer (the kind
> you
> might spray your roses with). Can anybody recommend a sprayer which
> is more
> durable than the garden one (which has a plastic hose with a metal
> tip), or
> one which has a more intense spray? It takes us forever to spray in
> 3/4
> gallon of water/soda solution.
>
> Thank you. Claire Reishman
>
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> _______________________________________________________________________
> _______
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>
Louis Katz
WIKI site http://www.tamucc.edu/wiki/Katz/HomePage
John Britt on tue 30 nov 04
Claire,
We solved this problem by having the beginning students make small flat
discs to put their work on(1/4" thick by 5" diameter or so). They had to
make a dozen or more and then bisque and kiln wash them. When they were
finished glazing a piece they then put their pieces on a disc to be
loaded. Solved a lot of problems!
Try the Grainger catalogue for a heavy duty sprayer,
Hope it helps,
John Britt
www.johnbrittpottery.com
Mark Knott on tue 30 nov 04
Claire, one option is to have your kiln shelves sand blasted to remove the glaze from the students mishaps. The second could be solved by cutting the tip off the sprayer and simple smash the tubing with a hammer. this allows a heavier soda stream to enter the kiln. This method works great in my kiln. mark knott
>
> From: Claire Reishman
> Date: 2004/11/30 Tue PM 06:02:11 EST
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: 2 soda/salt firing questions
>
> Hello Potters. I teach at St. Andrew's-Sewanee School in Tennessee, and we
> have both Bailey gas reduction kiln and a hand-built soda/salt kiln. I have
> two firing questions:
>
> 1) despite our most intense instruction, our students are not always
> very good about glazing pieces properly, and we often have running in both
> of our kilns from glazes which were applied too thickly. We try to grind
> off the runs with an electric hand-held grinder, and we've used a grinding
> wheel for metal and steel, and a grinding wheel for concrete. Both wheels
> wear down very quickly, we've found. My colleague and I recognize that the
> ultimate solution to this problem lies in teaching the students better about
> glazing, and eliminating the dripping. However, we have a group of shelves
> from our first firings of the year that have some serious glaze drips on
> them. Does anybody have a recommendation for a grinding tool which we could
> use on our shelves to remove glaze problems?
>
> 2) we use both soda and salt in our soda/salt kiln when firing, and
> we spray the soda/water solution in using a garden sprayer (the kind you
> might spray your roses with). Can anybody recommend a sprayer which is more
> durable than the garden one (which has a plastic hose with a metal tip), or
> one which has a more intense spray? It takes us forever to spray in 3/4
> gallon of water/soda solution.
>
> Thank you. Claire Reishman
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.802 / Virus Database: 545 - Release Date: 11/26/2004
>
> ______________________________________________________________________________
> 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.
>
Claire Reishman on tue 30 nov 04
Hello Potters. I teach at St. Andrew's-Sewanee School in Tennessee, and we
have both Bailey gas reduction kiln and a hand-built soda/salt kiln. I have
two firing questions:
1) despite our most intense instruction, our students are not always
very good about glazing pieces properly, and we often have running in both
of our kilns from glazes which were applied too thickly. We try to grind
off the runs with an electric hand-held grinder, and we've used a grinding
wheel for metal and steel, and a grinding wheel for concrete. Both wheels
wear down very quickly, we've found. My colleague and I recognize that the
ultimate solution to this problem lies in teaching the students better about
glazing, and eliminating the dripping. However, we have a group of shelves
from our first firings of the year that have some serious glaze drips on
them. Does anybody have a recommendation for a grinding tool which we could
use on our shelves to remove glaze problems?
2) we use both soda and salt in our soda/salt kiln when firing, and
we spray the soda/water solution in using a garden sprayer (the kind you
might spray your roses with). Can anybody recommend a sprayer which is more
durable than the garden one (which has a plastic hose with a metal tip), or
one which has a more intense spray? It takes us forever to spray in 3/4
gallon of water/soda solution.
Thank you. Claire Reishman
---
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Tarrant, Derek on wed 1 dec 04
Has anyone tried a small sand blaster?
There are several small hobby type models available that can cut very
precise lines. Although somewhat slow these should be ideal tools for
saving ceramics with flowed glaze as well as restoring shelves.
Regards,
Derek Tarrant
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Claire Reishman
Sent: Tuesday, November 30, 2004 6:02 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: 2 soda/salt firing questions
Hello Potters. I teach at St. Andrew's-Sewanee School in Tennessee, and we
have both Bailey gas reduction kiln and a hand-built soda/salt kiln. I have
two firing questions:
1) despite our most intense instruction, our students are not always
very good about glazing pieces properly, and we often have running in both
of our kilns from glazes which were applied too thickly. We try to grind
off the runs with an electric hand-held grinder, and we've used a grinding
wheel for metal and steel, and a grinding wheel for concrete. Both wheels
wear down very quickly, we've found. My colleague and I recognize that the
ultimate solution to this problem lies in teaching the students better about
glazing, and eliminating the dripping. However, we have a group of shelves
from our first firings of the year that have some serious glaze drips on
them. Does anybody have a recommendation for a grinding tool which we could
use on our shelves to remove glaze problems?
2) we use both soda and salt in our soda/salt kiln when firing, and
we spray the soda/water solution in using a garden sprayer (the kind you
might spray your roses with). Can anybody recommend a sprayer which is more
durable than the garden one (which has a plastic hose with a metal tip), or
one which has a more intense spray? It takes us forever to spray in 3/4
gallon of water/soda solution.
Thank you. Claire Reishman
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.802 / Virus Database: 545 - Release Date: 11/26/2004
____________________________________________________________________________
__
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.
Dorie Mickelson on wed 1 dec 04
Hi Claire, I suspect an angle grinder is what you might need for your
serious glaze runs on kiln shelves but expect that others with more
experience will respond about the best grinder for your situation. Just
wanted to suggest that once the kiln shelves are clean, in addition to
more/better glazing instruction for your students, you might want to
require that they use clay "coasters", "wasters", or "cookies" as they
are sometimes called. These are simply slabs of clay cut into circles
or squares of various sizes that get bisque fired and then put under
each piece of glazeware during the glaze firing. If a piece drips, it
drips onto the "coaster", thereby saving the kiln shelf.
I use "coasters" in my own kiln whenever I am testing new glazes or
using a particularly runny glaze combination that I fear might run off
the pot onto my shelves. The local potter's guild where I am taking
classes also has an approach I think is great for schools -- at the
beginning of the term, they ask each student to make 10-15 "wasters".
With about 30 students per term, this means that approximately 300-450
"wasters" get made, which then get bisque fired and put into the guild's
stash for everyone to use as needed. So a wide variety of shapes and
sizes of "wasters" are always available and kiln shelf glaze run damage
is minimized.
Alternately, you could require that any student whose pots drip on the
kiln shelves be responsible for grinding, scraping, cleaning, and
re-kiln washing the shelves. Once they've spent an entire afternoon
doing this, their glazing methods should improve significantly .
If you ever get new kiln shelves, you might also want to consider using
ITC instead of kiln wash, as it is apparently a miracle cure for glaze
spills (check the archives for more info on this if you're interested).
Regards,
Dorie Mickelson in wintry Ann Arbor, Michigan, where a new dusting of
snow covers all, and where I am once again waiting for my carefully
watched kiln to finish cooling so that I might unload my glaze fired
wares...
www.FreeSpiritCreations.com
From: Claire Reishman
Subject: 2 soda/salt firing questions
Hello Potters. I teach at St. Andrew's-Sewanee School in
Tennessee, and we have both Bailey gas reduction kiln and a hand-built
soda/salt kiln. I have two firing questions: 1) despite our most
intense instruction, our students are not always very good about glazing
pieces properly, and we often have running in both of our kilns from
glazes which were applied too thickly. We try to grind off the runs with
an electric hand-held grinder, and we've used a grinding wheel for metal
and steel, and a grinding wheel for concrete. Both wheels wear down very
quickly, we've found. My colleague and I recognize that the ultimate
solution to this problem lies in teaching the students better about
glazing, and eliminating the dripping. However, we have a group of
shelves from our first firings of the year that have some serious glaze
drips on them. Does anybody have a recommendation for a grinding tool
which we could use on our shelves to remove glaze problems?
Paul Herman on wed 1 dec 04
Claire,
You don't say what kind of kiln shelves you have.
If they are silicon carbide (black), they can be cleaned with a hammer
and chisel.
If they are clay or alumina (buff or white) it melts into the shelf, and
the grinder might be best. Did the shelves have wash on them? Wash
helps.
As for the students slopping too much glaze on there, only experience
will show them how to do it. And someone showing them how to do it
right....
best,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
----------
>From: Claire Reishman
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: 2 soda/salt firing questions
>Date: Tue, Nov 30, 2004, 3:02 PM
>
> However, we have a group of shelves
> from our first firings of the year that have some serious glaze drips on
> them. Does anybody have a recommendation for a grinding tool which we could
> use on our shelves to remove glaze problems?
Vince Pitelka on wed 1 dec 04
> Hello Potters. I teach at St. Andrew's-Sewanee School in Tennessee, and
> we
> have both Bailey gas reduction kiln and a hand-built soda/salt kiln. I
> have
> two firing questions:
Claire -
Hello neighbor! If glaze runs on the shelves are a serious recurring
problem, then you need to gear up for serious glaze grinding. Do this
outdoors, wearing a properly-fitting dust mask and impact resistant safety
goggles. Place the shelf on a folded towell or a piece of foam rubber when
grinding it. Never rest it on a hard unyielding surface while grinding - it
can crack the shelf.
You need a heavy cup stone to do a good job of grinding serious glaze runs.
Go to grainger.com and enter "6A080" in the search box. It will get you to:
Norton Rough Portable 5" Flaring Cup Wheel, Grainger part #6A080 - $17.48
each - Specification C-16Q for masonry or metal. I believe that they sell a
box of five stones for a lower price per stone, but you will have to call or
email them to find out.
This is not one of those cupped fiberglass-reinforced grinding disks. This
is a heavy, solid, cup-shaped grinding stone. You will nead a heavy-duty 7"
or 9" angle grinder to handle this cup stone. A smaller 4" or 5" angle
grinder will not do it. Appropriate models are the DeWalt model #DW840 or
the Milwaukee model #6098. Bosch, Makita, Hitachi, Porter Cable, and other
makers of high-quality power tools have similar models.
If you want to see this tool in action, take a drive up to the Craft Center
some time and I or my artist-in-residence Wes Smith will be happy to show it
to you, and you can try it out for yourself.
Good luck -
- 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/
Jo Smith on wed 1 dec 04
Vince,
How hard is the grinding dust on the grinder? We are having a family
arguement on this one. Thanks for the info on wadding on the platters, have
bonnie's video and want to work on some as soon as this last show is over.
Jo
Louis Katz on thu 2 dec 04
Grinders are supposedly designed to grind and most grindings are
abrasive. Even Iron Oxide is abrasive to some extent, but regardless,
the dust from the grinding wheels are usually silicon carbide. Nasty
abrasive stuff, unless you need nasty abrasive stuff in which case it
is helpful abrasive stuff unless we are talking edibles. In which case
hoagies. Then grinders should not have any abrasive stuff or you will
wear your teeth out on them. Submarines are particularly bad with
abrasive stuff in them as well.
Unlike grinders circular saws and belt sanders do not seem particularly
enamored with abrasives. Cutting marble and cement with abrasive blades
in my circular saw ( a cheapo) did it in. My Milwaukee 4x24 belt sander
developed a case of frozen bearings after spending a week sanding down
marble slabs. 10$ worth of new bearings fixed it even though the tool
repair shop said "not worth fixing" . I think they wanted to sell me a
new sander. Falling from a six foot high shelf finally did this
wonderful tool in. The shame of it. Five years and I am still sick
about this. If you have a dead Milwaukee 4x24" sander and want to sell
parts , let me know. I owe it to my sander to ask.
I have lived for the last ten years without a grinder and like it. I do
have to admit that my reduction shelves get funky, but for ten year old
Thorleys fired to a solid cone 10 they are doing remarkably well. I
fair number of cracks.
I chisel off glaze only when the shelf is supported over its entire
length. I use a bed of sand contained in a 1.5" tall box made of 2x2's
and plywood. It is filled with coarse construction sand. The fine stuff
blows away in wind storm. I have a series of drain holes as when we get
a real storm the box fills up with water blown under the roof. I have
to change the sand about twice a year. I use a 12" wide wall paper
brush to brush the sand off the shelf back.
I use an old brick, hard brick , for rubbing the slat crud from shelf
backs. This practice and other like it my be the reason I have hand
trouble, but heavy grinders have been a problem for a long time with
me. something about vibration and holding them up, bugs my elbows.
If you use a chisel on shelves sharpen only one side and do sharpen it!
Use it with the sharpened face parallel to the shelf surface and it
will work better and stay sharper longer. Dress the edges and the top
of the handle keeping the mushrooming end ground down. Yes your 15$
chisel will wear out if you sharpen it, but even then it takes a long
time.
Goggles, gloves, respirator required.
Louis
Thinking too much about food. More dinner needed.
Vince Pitelka on thu 2 dec 04
> How hard is the grinding dust on the grinder? We are having a family
> arguement on this one. Thanks for the info on wadding on the platters,
> have
> bonnie's video and want to work on some as soon as this last show is over.
Jo -
When grinding shelves, it won't hurt the grinder at all - no noticeable
effect. As mentioned, do this outdoors, and the grindings will be directed
away from the grinder. I've been grinding shelves with a heavy angle
grinder and cup stone for several decades, and have never seen it damage the
grinder. Six or seven years ago we bought a DeWalt 7" angle grinder at the
Craft Center, and have been using it ever since for this taxk. Before that,
we were using the Sioux 7" angle grinder that I have been using for the last
25.
Good luck -
- 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/
Ivor and Olive Lewis on thu 2 dec 04
Dear Claire Reishman,
You may already get your students to do this, but one of the rules
imposed on me, and one which I imposed on my students saved a lot of
cleaning and a lot of embarrassment.
Work that had been coated with glaze had to be clean and clear of
glaze across the base and up the wall for half an inch.
This cannot apply for earthen ware but then the solution is the
minimum of glaze to do the job and a good supply of star stilts.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Lee Love on thu 2 dec 04
Paul Herman wrote:
>
>If they are silicon carbide (black), they can be cleaned with a hammer
>and chisel.
>
>
I use a broad flat chisel to wack glaze drips off of my
silicon carbide shelves. Most come off without the need of a hammer.
For introducing larger amounts of solution quickly into the
kiln, one time a NCC, I use a pipe (like muffler pipe) with a Tee
joint. The short part of the Tee, (bottom pipe) was place in the
solution bucket. A hose connected to the exhaust of a shop vac was
attached to the short end of the top of the Tee. The long end was
stuck in the soda port. This will introduce large amounts of solution
in a short amount of time, so you have to be careful (don't aim it
directly at the pots.) I prefer using a garden sprayer.
If you keep the solution warm you can have a higher
concentration of soda in the solution.
--
in Mashiko, Japan http://mashiko.org
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