barblund on sat 5 feb 05
Hi Folks- I've been off Clayart for many months now, making and selling =
pots, but it is time to be back, I am glad!
I have just finished chiseling glaze and clay shards off my shelves yet =
again. (^6-7 electric)Yes, it is a runny glaze, but not all of the time- =
this time it was. My troubles with the glaze are probably my fault- a =
grumble indeed, but not this one!
So, my grumble is, that, the kiln wash doesn't seem to serve any purpose =
in protecting the shelves! No matter what, I have to dig down into the =
shelf to get the glaze drips off. Nothing just "lifts" off!. Pots stick =
to the shelf and break off with or without kiln wash- so what is the =
point! I prefer using a wash that scrapes off fairly easily so I can =
flip my shelves over. I am using 80% alumina hydrate and 20% EPK as a =
kiln wash at the moment. It does scrape off with effort, but it is =
better than what I had been using before.
So, does kiln wash serve to protect the shelves or just to help pots =
slide along the shelves during firing? I am about ready to ditch kiln =
wash all together since I have to chisel the shelves anyway.=20
I have a read a bit of the archives discussions on ceramic paper. I am =
tempted to find a regional supplier and use that under the suspect pots. =
Has that been working for folks? And which kind is "best?" I would try =
to limit its use because of the air pollution issue- wear a mask while =
loading the kiln etc. What happens to the pots when the glaze runs and =
sticks to it?
Any thoughts would be appreciated!
Barb from Bloomington
barblund@bluemarble.net
520 West 6th St.
Bloomington, IN 47404
812 339 8476
Cindy in SD on sun 6 feb 05
Dear Barb,
Nothing you use, probably not even ITC, will keep large glaze drips from
sticking and having to be ground off your shelves. You simply must find
a way to avoid allowing this glaze to drip excessively. If you can't
control the glaze at all and you need to keep using it, you need to fire
your pottery on disposable clay cookies to protect your shelves. I've
used commercially made stilts up to ^6, though they're actually made for
low fire. A well-placed stilt or short kiln post will keep your pot from
sticking to the cookie.
Some other ways to keep the glaze from reaching your shelves:
* Create some sort of barrier in the actual pot, such as a raised
bead or a decorative groove or similar at or near the foot.
* Use the glaze only on the upper portions of your pot.
* Apply the glaze more thinly. Keep in mind that thick-walled pots
will automatically attract more glaze when dipping or pouring. You
can dampen these pots before glazing them, or you can glaze them
last, and thin the glaze out a bit before you do them. Your glaze
coat should be around the thickness of a credit card for most glazes.
* Iron red glazes are famous for dripping. Be extra careful with them.
Hope this helps,
Cindy in SD
william schran on sun 6 feb 05
Barb from Bloomington wrote:> I am using 80% alumina hydrate and
20% EPK as a kiln wash at the moment. It does scrape off with
effort, but it is better than what I had been using before.
So, does kiln wash serve to protect the shelves or just to help pots
slide along the shelves during firing? I am about ready to ditch
kiln wash all together since I have to chisel the shelves anyway. <
If you're continuing to have issues with a single glaze running, then
perhaps that glaze might need some adjustment to get it more stable
at top temperature. Without the recipe, it's hard to determine what
adjustments would work best, but you may want to do some tests by
adding small increments (5%) of silica or clay.
As for the shelves, a few coats of kiln wash is probably necessary to
protect the shelf. A single thin coat probably won't do the job. I
use a recipe of 50% Alumina & 50% EPK, mixed with water to the
consistency of half & half. I use a small cheap paint roller to apply
one coat in a single direction, then a second coat in an adjacent
direction.
I would think if you had no kiln wash on the shelves, your shelves
would look like the surface of the moon in quick order - that is if
you didn't break the shelves chiseling the glaze off.
Hope this helps, Bill
Victoria E. Hamilton on sun 6 feb 05
Barb,
We use the following recipe for kiln wash - seems to work fine 95% of the
time:
Equal parts EPK, Alumina Hydrate & Silica. Some of these ingredients are
heavier than others and may settle to the bottom of the bucket, so stirring
often helps to bring equal parts of all ingredients up into the water for
application to your shelves.
We have found that 2 or 3 very thin coats of wash works a little better than
1 coat heavily applied.
Victoria Hamilton
Millennia Antica Pottery
Seattle, WA
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of barblund
Sent: Saturday, February 05, 2005 18:59
To: CLAYART@LSV.CERAMICS.ORG
Subject: kiln shelf grumble
Hi Folks- I've been off Clayart for many months now, making and selling
pots, but it is time to be back, I am glad!
I have just finished chiseling glaze and clay shards off my shelves yet
again. (^6-7 electric)Yes, it is a runny glaze, but not all of the time-
this time it was. My troubles with the glaze are probably my fault- a
grumble indeed, but not this one!
So, my grumble is, that, the kiln wash doesn't seem to serve any purpose in
protecting the shelves! No matter what, I have to dig down into the shelf
to get the glaze drips off. Nothing just "lifts" off!. Pots stick to the
shelf and break off with or without kiln wash- so what is the point! I
prefer using a wash that scrapes off fairly easily so I can flip my shelves
over. I am using 80% alumina hydrate and 20% EPK as a kiln wash at the
moment. It does scrape off with effort, but it is better than what I had
been using before.
So, does kiln wash serve to protect the shelves or just to help pots slide
along the shelves during firing? I am about ready to ditch kiln wash all
together since I have to chisel the shelves anyway.
I have a read a bit of the archives discussions on ceramic paper. I am
tempted to find a regional supplier and use that under the suspect pots.
Has that been working for folks? And which kind is "best?" I would try to
limit its use because of the air pollution issue- wear a mask while loading
the kiln etc. What happens to the pots when the glaze runs and sticks to
it?
Any thoughts would be appreciated!
Barb from Bloomington
barblund@bluemarble.net
520 West 6th St.
Bloomington, IN 47404
812 339 8476
____________________________________________________________________________
__
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.
clennell on sun 6 feb 05
Sour Cherry Pottery
> Hi Folks- I've been off Clayart for many months now, making and selling pots,
> but it is time to be back, I am glad!
>
> I have just finished chiseling glaze and clay shards off my shelves yet again.
> (^6-7 electric)Yes, it is a runny glaze, but not all of the time- this time it
> was. My troubles with the glaze are probably my fault- a grumble indeed, but
> not this one!
>
> So, my grumble is, that, the kiln wash doesn't seem to serve any purpose in
> protecting the shelves! No matter what, I have to dig down into the shelf to
> get the glaze drips off. Nothing just "lifts" off!. Pots stick to the shelf
> and break off with or without kiln wash- so what is the point! I prefer using
> a wash that scrapes off fairly easily so I can flip my shelves over. I am
> using 80% alumina hydrate and 20% EPK as a kiln wash at the moment. It does
> scrape off with effort, but it is better than what I had been using before.
>
Barb; Our kiln wash is 50 Alumina hydrate, 25 kaolin and 25 silica. You can
put it on pretty thick and the wash will lift off the shelf if you have a
melter. This going to save you some back work and some money. Alumina is
expensive.
Cheers,
Tony
Paul Herman on mon 7 feb 05
Hi Lee,
Try fine sawdust mixed in your wadding. It works great.
wad away,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
----------
>From: Lee Love
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: kiln shelf grumble
>Date: Mon, Feb 7, 2005, 6:36 AM
>
> clennell wrote:
>
>>Barb; Our kiln wash is 50 Alumina hydrate, 25 kaolin and 25 silica. You can
>>put it on pretty thick and the wash will lift off the shelf if you have a
>>melter. This going to save you some back work and some money. Alumina is
>>expensive.
>>
>>
> You got me thinking about my kiln wads, with your mentioning
> of silica Tony. I picked up some rice husks, which are predominantly
> silica. I use a layer of the husks under flat "sushi" or "horse
> dervies" plate (I do a spiral wire cut on the bottom and inlay with
> contrasting clay) as a movable, not-stick surface to help keep the
> platters from cracking. But you gave me an idea (mixed with
> something someone here said about putting flour in wads to make them
> crumbly): I am going to wedge some of the husks into my
> alumina/kaolin wadding material. I am thinking this will make the
> wads more "crumbly."
>
> --
> in Mashiko, Japan
Paul Herman on mon 7 feb 05
Kate,
I'll try to answer below:
----------
>From: Kate Johnson
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: kiln shelf grumble
>Date: Mon, Feb 7, 2005, 11:52 AM
>
> all too often I have a glazed piece spoiled by
> a piece of kiln wash that's popped into my glaze while firing--perhaps
> chipping or flaking off the shelf above, I don't know. As I've mentioned
> before, I don't have my own kiln and don't have much control over kiln
> maintenance or loading, so I have a twofold question--
>
> So, #1--IS there anything I can do to minimize or fix this kind of damage?
> Sometimes I can dig or pop the speck of kiln wash off and it's not too bad,
> but it does usually leave a dull spot I'm not happy with. Other times, the
> piece is just completely unusable or REALLY had to be labeled a second. Is
> it possible to grind or scrape off this spot of wash, then reglaze?
You could grind it out and reglaze/fire the piece. It sounds like you
need a kiln of your own. Then you wouldn't have to subject your hard
work to a careless kiln operator.
>
> #2--I volunteered to put fresh kiln wash on recently, when someone used a
> particularly drooly crystal glaze and I didn't want my stuff contaminated.
> I was going to scrape all the old junk off first, but was told just to put
> wash over it, so I did.
This cements it. The person who told you that is not taking good care of
the kiln, hence your work. DUMP THEM!!! They are not taking the proper
care, and should be fired or re-educated. Find a better kiln operator or
get your own kiln somehow. It sounds like it's time for you to take
control of the entire process.
Independance rules,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
Lee Love on mon 7 feb 05
barblund wrote:
>
>I have just finished chiseling glaze and clay shards off my shelves yet again.
>
Barb,
Make yourself some clay pads to put under pots you think might
run. Wash them like you would a kiln shelf. You can reuse them.
--
in Mashiko, Japan http://mashiko.org
http://potters.blogspot.com/ WEB LOG
http://claycraft.blogspot.com/ Photos!
Lee Love on mon 7 feb 05
clennell wrote:
>Barb; Our kiln wash is 50 Alumina hydrate, 25 kaolin and 25 silica. You can
>put it on pretty thick and the wash will lift off the shelf if you have a
>melter. This going to save you some back work and some money. Alumina is
>expensive.
>
>
You got me thinking about my kiln wads, with your mentioning
of silica Tony. I picked up some rice husks, which are predominantly
silica. I use a layer of the husks under flat "sushi" or "horse
dervies" plate (I do a spiral wire cut on the bottom and inlay with
contrasting clay) as a movable, not-stick surface to help keep the
platters from cracking. But you gave me an idea (mixed with
something someone here said about putting flour in wads to make them
crumbly): I am going to wedge some of the husks into my
alumina/kaolin wadding material. I am thinking this will make the
wads more "crumbly."
--
in Mashiko, Japan http://mashiko.org
http://potters.blogspot.com/ WEB LOG
http://claycraft.blogspot.com/ Photos!
Kate Johnson on mon 7 feb 05
Barb wrote:
> So, does kiln wash serve to protect the shelves or just to help pots
> slide along the shelves during firing? I am about ready to ditch
> kiln wash all together since I have to chisel the shelves anyway. <
So, this reminds me--I don't remember ever having seen a kiln wash problem
I've encountered WAY too many times in my 4 years of messing about with
pots, etc., though I may have just missed it.
I'm not sure why this is, but all too often I have a glazed piece spoiled by
a piece of kiln wash that's popped into my glaze while firing--perhaps
chipping or flaking off the shelf above, I don't know. As I've mentioned
before, I don't have my own kiln and don't have much control over kiln
maintenance or loading, so I have a twofold question--
So, #1--IS there anything I can do to minimize or fix this kind of damage?
Sometimes I can dig or pop the speck of kiln wash off and it's not too bad,
but it does usually leave a dull spot I'm not happy with. Other times, the
piece is just completely unusable or REALLY had to be labeled a second. Is
it possible to grind or scrape off this spot of wash, then reglaze?
#2--I volunteered to put fresh kiln wash on recently, when someone used a
particularly drooly crystal glaze and I didn't want my stuff contaminated.
I was going to scrape all the old junk off first, but was told just to put
wash over it, so I did.
One of the other shelves had a lot of crazing on the kiln wash itself--it
looked like a dry riverbed in the southwest! Again, I was told just to put
fresh wash over it. Erk...not sure that really made it safe, but that's
what I did.
If I do this again in the future--or rather WHEN I do this again!--should I
insist on scraping off all the old gunk first to minimize the kind of
possible flaking that's ending up in my glaze? Most of the rest of the
stuff glazed is high school students' work--not good to have bits of crud in
the glaze, but they're not hoping to produce professional work. I am.
Suggestions, guidance? Many thanks, as always...
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
Betty Burroughs on mon 7 feb 05
Hi Barb,
Whenever I have pieces to fire with a runny glaze I place them on =
bisqued "cookies." The glaze may run onto the cookie which can then be =
knocked off and the bottom of the pot ground and sanded. Sure saves my =
kiln shelves!=20
I make these "cookies" out of recycled clay rolled out about 1/8 to 1/4 =
inch thick and cut to fit slightly larger than the pot bottoms. I make a =
variety of sizes and have them bisqued and ready to use when I do a =
glaze fire.
I used to find pots that stuck to the kiln shelves were often =
losers.....they would break trying to pry them off. I now have more =
luck saving the pots with these cookies.
Hope this helps.
Betty B
--------Original Message...............
Date: Sat, 5 Feb 2005 21:59:28 -0500
From: barblund
Subject: kiln shelf grumble
....So, my grumble is, that, the kiln wash doesn't seem to serve any =
purpose =3D
in protecting the shelves! No matter what, I have to dig down into the =
=3D
shelf to get the glaze drips off. Nothing just "lifts" off!. Pots stick =
=3D
to the shelf and break off with or without kiln wash- so what is the =3D
point! I prefer using a wash that scrapes off fairly easily so I can =
=3D
flip my shelves over. I am using 80% alumina hydrate and 20% EPK as a =
=3D
kiln wash at the moment. It does scrape off with effort, but it is =3D
better than what I had been using before.
So, does kiln wash serve to protect the shelves or just to help pots =3D
slide along the shelves during firing? I am about ready to ditch kiln =
=3D
wash all together since I have to chisel the shelves anyway.=3D20
I have a read a bit of the archives discussions on ceramic paper. I am =
=3D
tempted to find a regional supplier and use that under the suspect pots. =
=3D
Has that been working for folks? And which kind is "best?" I would try =
=3D
to limit its use because of the air pollution issue- wear a mask while =
=3D
loading the kiln etc. What happens to the pots when the glaze runs and =
=3D
sticks to it?
Any thoughts would be appreciated!
Barb from Bloomington
barblund@bluemarble.net
520 West 6th St.
Bloomington, IN 47404
812 339 8476
Ivor and Olive Lewis on mon 7 feb 05
Dear Barb,
If you have a glaze that is erratic then it would pay you to find out
why because the wash you are using should cope with minor accidents
provided it is of adequate thickness and it should break away after
firing because it is a highly refractory material. Pots should not
weld themselves to the shelf
One thing done by some potters is to "Comb" the thick kiln wash as
soon as it is applied. You can have a lot of fun with the patterns but
the idea is that being thick and thin it fractures easily and just
falls away from the shelf.
I use a granular material to assist movement due to expansion and
contraction, #100 Alumina sand.
Perhaps you would care to tell us a bit more about this glaze and the
type of clay on which it is being used.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Hi Folks- I've been off Clayart for many months now, making and
selling pots, but it is time to be back, I am glad!
I have just finished chiseling glaze and clay shards off my shelves
yet again. (^6-7 electric)Yes, it is a runny glaze, but not all of the
time- this time it was. My troubles with the glaze are probably my
fault- a grumble indeed, but not this one!
So, my grumble is, that, the kiln wash doesn't seem to serve any
purpose in protecting the shelves! No matter what, I have to dig down
into the shelf to get the glaze drips off. Nothing just "lifts" off!.
Pots stick to the shelf and break off with or without kiln wash- so
what is the point! I prefer using a wash that scrapes off fairly
easily so I can flip my shelves over. I am using 80% alumina hydrate
and 20% EPK as a kiln wash at the moment. It does scrape off with
effort, but it is better than what I had been using before.
So, does kiln wash serve to protect the shelves or just to help pots
slide along the shelves during firing? I am about ready to ditch kiln
wash all together since I have to chisel the shelves anyway.
I have a read a bit of the archives discussions on ceramic paper. I
am tempted to find a regional supplier and use that under the suspect
pots. Has that been working for folks? And which kind is "best?" I
would try to limit its use because of the air pollution issue- wear a
mask while loading the kiln etc. What happens to the pots when the
glaze runs and sticks to it?
Any thoughts would be appreciated!
Barb from Bloomington
barblund@bluemarble.net
520 West 6th St.
Bloomington, IN 47404
812 339 8476
______________________________________________________________________
________
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.
Kate Johnson on tue 8 feb 05
Hi Paul--thank you for answering!
Is
>> it possible to grind or scrape off this spot of wash, then reglaze?
>
> You could grind it out and reglaze/fire the piece.
That's what I was hoping. Some of these are the nice marbleware
pieces--everything was go till that tiny fleck turned it into a second.
It's a pain to reglaze and refire, but it's better than losing the whole
effort, when it basically looks darn good.
It sounds like you
> need a kiln of your own. Then you wouldn't have to subject your hard
> work to a careless kiln operator.
>
AMEN. That will probably be on the table a year or so from now. Right now
the finances don't allow for it, nor the condition of the place I'd have to
put the kiln. I'm looking at rewiring, venting, possibly shoring up the
floor after getting rid of the termites, THEN investing in the kiln...
Besides, I really want to try all these wonderful ramping and holding
suggestions I keep reading about but have no control over...
>>
>> #2--I volunteered to put fresh kiln wash on recently, when someone used a
>> particularly drooly crystal glaze and I didn't want my stuff
>> contaminated.
>> I was going to scrape all the old junk off first, but was told just to
>> put
>> wash over it, so I did.
>
> This cements it. The person who told you that is not taking good care of
> the kiln, hence your work. DUMP THEM!!! They are not taking the proper
> care, and should be fired or re-educated.
If I were paying for the privilege at a professional potter's kiln, I'd
definitely feel that way, I think. This is a friend who is an overworked
high school teacher. A whole LOT of work goes through that kiln, most of it
highly amateur. (The kids seem to love those nasty crystal glazes that
drool on the shelves.) But--he charges me no more than any of the other
adults in the continuing ed class, though I do a lot of work at home and
bring it in to be fired.
I'm still what I think of as the apprenticing stage, though to the past and
to my ClayArt gurus and book writers, since he and I do very different kinds
of work. I have a lot to learn, in other words, and am busy solving a wide
range of technical problems, from that pesky lead-free honey glaze challenge
to getting the clay rolled out evenly and finding the perfect timing, as a
handbuilder.
(Ooooh, just got a wonderful 18th c. style coggling tool made by a friend
who does period woodworking--traded him one of my redware "drinking cans.")
My other option here, I think, is to volunteer my time to do the kiln
maintenance right, since I'm the one who cares most. The budget at
school is pretty horrifying, for the kids in the arts classes--something
like $6 a semester for supplies. Oh, right. (Big sports town...) Anyway,
if I do the work, we all benefit, that way...
Occasionally I donate something I want to use anyway, like plaster or glaze.
Sounds like I need to invest in a supply of kiln wash so I can keep the
shelves in good shape...
Find a better kiln operator or
> get your own kiln somehow. It sounds like it's time for you to take
> control of the entire process.
YUM. Control rocks!
>
> Independance rules,
>
And I am a MOST independent old broad, yep. 'Tis on my agenda, the long
range plan...
Best--
Kate
Sam Hoffman on tue 8 feb 05
Hi Lee-
We typically use equal parts fireclay and sawdust for a wadding
mixture. Last firing, there was no sawdust available, so we used rice
hulls instead. They worked beautifully in terms of making the wads
more crumbly after firing, and seemed to lend strength during loading.
The only complaint was that the hulls are rather sharp and pricked your
finger if you pressed a wad the wrong way.
My favorite wadding recipe for anagama is equal parts fireclay, sand,
silica, and sawdust. Easy to load with, comes off easily, and leaves
nice flashmarks.
I'm still curious how your Yohen tests came out. Will charcoal work
in your kiln?
Take care,
Sam
S.L. Hoffman Pottery
Corvallis, Oregon
www.samhoffman.com
On Feb 7, 2005, at 6:36 AM, Lee Love wrote:
> clennell wrote:
>
>> Barb; Our kiln wash is 50 Alumina hydrate, 25 kaolin and 25 silica.
>> You can
>> put it on pretty thick and the wash will lift off the shelf if you
>> have a
>> melter. This going to save you some back work and some money.
>> Alumina is
>> expensive.
>>
>>
> You got me thinking about my kiln wads, with your mentioning
> of silica Tony. I picked up some rice husks, which are predominantly
> silica. I use a layer of the husks under flat "sushi" or "horse
> dervies" plate (I do a spiral wire cut on the bottom and inlay with
> contrasting clay) as a movable, not-stick surface to help keep the
> platters from cracking. But you gave me an idea (mixed with
> something someone here said about putting flour in wads to make them
> crumbly): I am going to wedge some of the husks into my
> alumina/kaolin wadding material. I am thinking this will make the
> wads more "crumbly."
>
> --
> in Mashiko, Japan http://mashiko.org
> http://potters.blogspot.com/ WEB LOG
> http://claycraft.blogspot.com/ Photos!
>
> _______________________________________________________________________
> _______
> 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.
>
Sue Leabu on tue 8 feb 05
Adding wheat or oat bran works also works great added to wadding. Most wads
that are stuck will pop right off if the pot is soaked in water overnight.
Sue
Kalamazoo, MI
Paul Herman wrote:
>Hi Lee,
>
>Try fine sawdust mixed in your wadding. It works great.
>
>wad away,
>
>Paul Herman
>
>Great Basin Pottery
>Doyle, California US
>http://www.greatbasinpottery.com/
>
Lee Love on wed 9 feb 05
Sam Hoffman wrote:
> Hi Lee-
>
> We typically use equal parts fireclay and sawdust for a wadding
> mixture. Last firing, there was no sawdust available, so we used rice
> hulls instead. They worked beautifully in terms of making the wads
> more crumbly after firing, and seemed to lend strength during loading.
> The only complaint was that the hulls are rather sharp and pricked your
> finger if you pressed a wad the wrong way.
Thanks for the info Sam. I mixed some nuka with my fire clay. I got
coarse fireclay last time and you could swear it was dirt road gravel.
:-) Not so good for wadding. I'll try mixing some with my
alumina/kaolin wadding.
> My favorite wadding recipe for anagama is equal parts fireclay,
> sand,
> silica, and sawdust. Easy to load with, comes off easily, and leaves
> nice flashmarks.
I will try this too. I use shells on the larger stuff.
> I'm still curious how your Yohen tests came out. Will charcoal
> work
> in your kiln?
I made a big mistake with the stuff I put in
saggers: There are two kinds of rice straw rope, and I mistakenly got
the more refractory kind. The softer kind is made of round strands
rather than flat. My dyslexia had me picking up the wrong kind. The
rope held its shape where it was covered by the saggers and the rope on
the top of work left slivers of glass
Also, because I filled the front half of the kiln with a
lot of plates, I blocked off a lot of the flame travel. I have
dried out some saggers I will put the plates in next time. It will
protect them from ash and I won't half to pack so many shelves in so
tight together.
The charcoal in the saggers (they were bowls that
covered half to 3/4rds of the bottom of some Bizen clay) didn't work too
well. The charcoal turned to glaze and pooled in spots. It didn't
cause as much variation as I hoped for.
I am having good luck with the smooth terracotta, which
flashes better and has more surface variety than the bizen clay.
What I want to do with this, because it gets plenty hot enough for the
terracotta in my flue channel, is try pouring charcoal into the channel
on top of terracotta work. Can't do it this time, maybe next firing.
I also picked up Seger cones 8, 9 and 10. I will fire
them next to Orton 8, 9, 10, 11, 12 and 13 and see how close they are.
--
Lee in Mashiko, Japan http://mashiko.org
http://potters.blogspot.com/ WEB LOG
http://claycraft.blogspot.com/ Photos!
Ivor and Olive Lewis on thu 10 feb 05
I notice several postings on this topic are advocating waddings and
kiln washes that have Silica as an ingredient.
Any comments?
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
lela martens on thu 10 feb 05
>
>I notice several postings on this topic are advocating waddings and
>kiln washes that have Silica as an ingredient.
>Any comments?
>Best regards,
>Ivor Lewis.
>Redhill,
>S. Australia.
>
.. Yes actually, since you ask, Ivor. The thought occurs, but I figured I
was missing something.. Silica is or is very much like flint..glass. Melts,
runs, turns very hard again upon cooling. It seems to me to be one of the
last materials to use in a kiln wash, like purposely applying what one is
trying to avoid. I would try it if my aim was to securely attach my pots to
the shelf.
Since none of those who know much more than I didn`t remark, I assumed I had
confused something, but still would never use for anything not wanting to
get stuck.
Thanks ,
Lela______________________________________________________________________________
>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.
Paul Herman on thu 10 feb 05
Greetings Ivor,
No added ground silica in either my wadding or kiln wash. I want to
avoid putting "glass formers" under the foot. The wadding does have some
70 mesh sand.
I use alumina/kaolin in the wash, but only clay, sand and sawdust for
wads. Alumina is expensive, and when I've seen it used in wads, it
leaves a nasty white spot that is hard to remove.
best,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
----------
>From: Ivor and Olive Lewis
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: kiln shelf grumble
>Date: Wed, Feb 9, 2005, 8:35 PM
>
> I notice several postings on this topic are advocating waddings and
> kiln washes that have Silica as an ingredient.
> Any comments?
> Best regards,
> Ivor Lewis.
> Redhill,
> S. Australia.
Lester Haworth on fri 11 feb 05
Silica or Flint is a standard ingredient in many kiln wash recipes. It has a
melting point of 2876 deg. F. That's cone 21 or 22 aprox. I don't know many
people who fire that hot. I use about fifty percent in my recipes for kiln
wash. Kiln wadding no silica, just 50% EPK & 50% alumina made into a firm
moldable paste.
Les H.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of lela martens
Sent: Thursday, February 10, 2005 9:43 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: kiln shelf grumble
>
>I notice several postings on this topic are advocating waddings and
>kiln washes that have Silica as an ingredient.
>Any comments?
>Best regards,
>Ivor Lewis.
>Redhill,
>S. Australia.
>
.. Yes actually, since you ask, Ivor. The thought occurs, but I figured I
was missing something.. Silica is or is very much like flint..glass. Melts,
runs, turns very hard again upon cooling. It seems to me to be one of the
last materials to use in a kiln wash, like purposely applying what one is
trying to avoid. I would try it if my aim was to securely attach my pots to
the shelf.
Since none of those who know much more than I didn`t remark, I assumed I had
confused something, but still would never use for anything not wanting to
get stuck.
Thanks ,
Lela________________________________________________________________________
______
>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.
____________________________________________________________________________
__
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.
lela martens on fri 11 feb 05
Mentally connecting silica with glass, I personally stear clear of silica in
my kiln shelf wash. Without a flux the sticking would likely not occur at
usual glaze melting temperatures, so would not fix the ware as I imagined.
Perhaps a phobic reaction caused by an instructor relating his doing a
favour to the one lending him the use of studio. He had spent an afternoon
carefully cleaning and applying a new coat of wash to all the shelves. It
turned out to be a newly mixed but misplaced and unlabeled glaze.
Lela
Lee Love on fri 11 feb 05
Ivor and Olive Lewis wrote:
>I notice several postings on this topic are advocating waddings and
>kiln washes that have Silica as an ingredient.
>Any comments?
>
>
I use rice husks (nuka) under platters. It is mostly silica.
--
in Mashiko, Japan http://mashiko.org
http://potters.blogspot.com/ WEB LOG
http://claycraft.blogspot.com/ Photos!
william schran on sat 12 feb 05
Tony wrote:>Reading Hoppers new very thorough book "Making Marks" he
refers to silica as the bones of a glaze. That is exactly why i
advocate it in my kiln wash for the gas kiln-it gives the wash
strength.<
Tony, hmmmmmm... if silica is the "bones" of a glaze, essentially the
glass former, wouldn't one want the kiln wash to contain nothing that
would create glass?
I understand the argument about silica's high melting point, though
it still has the same high melting point in the glaze, until the
fluxes begin to work on it.
Suppose one had a glaze that ran quite a bit down on to the kiln
shelf. Couldn't the glaze possibly combine with the silica in the
kiln wash and create another glaze?
For many years I used the 50/50 kaolin/silica wash. But after working
with crystalline glazes for a period of time, I found using alumina
and now have changed to kaolin to use as a separating agent between
pot and pedestal, to work very well in removing the firing pedestal
from the pot - and there is often a considerable amount of glaze
covering the seam between pot & pedestal.
So I've switched to a 50/50 by volume mix of alumina & kaolin for my
kiln wash and have very rarely had to chisel into the shelf after
many firings of student work.
My 2 cents, Bill
clennell on sun 13 feb 05
Sour Cherry Pottery
> Mentally connecting silica with glass, I personally stear clear of silica in
> my kiln shelf wash. Without a flux the sticking would likely not occur at
> usual glaze melting temperatures, so would not fix the ware as I imagined.
>
> Perhaps a phobic reaction caused by an instructor relating his doing a
> favour to the one lending him the use of studio. He had spent an afternoon
> carefully cleaning and applying a new coat of wash to all the shelves. It
> turned out to be a newly mixed but misplaced and unlabeled glaze.
>
> Lela
Lela: Because an instructor used glaze to wash the kiln shelves is a rather
lame reason not to use a kiln wash that contains silica. Reading Hoppers
new very thorough book "Making Marks" he refers to silica as the bones of a
glaze. That is exactly why i advocate it in my kiln wash for the gas kiln-
it gives the wash strength.
I once had a summer student that glazed my kiln shelves with feldspar
instead of kaolin. Oh yeah, those pots stuck. It didn't put me off using
kiln wash, just made me be sure to label the bags or buckets.
Cheers,
Tony
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King Street
Beamsville, Ontario
CANADA L0R 1B1
http://www.sourcherrypottery.com
http://www.sourcherrypottery.com/current_news/news_letter.html
Craig Clark on sun 13 feb 05
I don't know whether or not this has been metioned on this thread
but we used alumina hydrate that we sifted onto all of our kiln shelves
while I was in school. It worked very well. We just had an old cart with
about a four inch ressessed top. We would place the shelves one by one
on a brick inside the cart, reach down with the old sifter into the
recess where the alumina hydrate was stored and then sprinkle lightly
all over the shelf. The shelves were 12x24x1 and used extensively in a
60 cubic foot alpine updraft. The kiln ran off power burners and we
pushed it pretty hard.
We also had an 80 cubic foot salt inwhich we ran carborundum shelves
that we got from some outfit up in NewJersey (don't remember the name
off hand) but we did the same thing. Granted we would ocassionally need
to grind the shelves a bit from the salt but not very much.
Before putting a shelf into the kiln just run your thumb around the
upper edge to give yourself a nice clean line about 1/8 inch wide or so.
After the firings we would just dump the hydrate back into the top of
the cart. Didn't loose much material that way.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
Eva Gallagher on sun 13 feb 05
Hi Bill,
I have to agree - at least in electric - the 50/50 alumina kaolin works much
better at removing glaze runs, especially those that have melted deep into
the wash. It also does not flake like the one that used to have silica, yet
scrapes off more easily.
Also my 2 cents,
Eva
Deep River, Ontario
----- Original Message -----
From: "william schran"
To:
Sent: Saturday, February 12, 2005 3:18 PM
Subject: Re: kiln shelf grumble
> Tony wrote:>Reading Hoppers new very thorough book "Making Marks" he
> refers to silica as the bones of a glaze. That is exactly why i
> advocate it in my kiln wash for the gas kiln-it gives the wash
> strength.<
>
> Tony, hmmmmmm... if silica is the "bones" of a glaze, essentially the
> glass former, wouldn't one want the kiln wash to contain nothing that
> would create glass?
>
> I understand the argument about silica's high melting point, though
> it still has the same high melting point in the glaze, until the
> fluxes begin to work on it.
>
> Suppose one had a glaze that ran quite a bit down on to the kiln
> shelf. Couldn't the glaze possibly combine with the silica in the
> kiln wash and create another glaze?
>
> For many years I used the 50/50 kaolin/silica wash. But after working
> with crystalline glazes for a period of time, I found using alumina
> and now have changed to kaolin to use as a separating agent between
> pot and pedestal, to work very well in removing the firing pedestal
> from the pot - and there is often a considerable amount of glaze
> covering the seam between pot & pedestal.
>
> So I've switched to a 50/50 by volume mix of alumina & kaolin for my
> kiln wash and have very rarely had to chisel into the shelf after
> many firings of student work.
>
> My 2 cents, Bill
>
> ______________________________________________________________________________
> 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.
| |
|
