gary navarre on mon 21 dec 09
Hay Folks,=3D0A=3D0A My guess on the stain is iron residue from your water.=
=3D0A=3D
=3D0A I too am wondering about drying a couple of these kind of shelves tha=
t =3D
had been outside in the weather for a long time. I've had them to ^10-11 ye=
=3D
ars ago and one got warped like a bird wing so it might be a bit more vitri=
=3D
fied. Looking at a broken corner the body seems rather course so I wonder i=
=3D
f it is sufficiently refractory and open enough to "breathe" as opposed the=
=3D
the Advancers which seem to be highly vitrified and trap moisture more tha=
=3D
n oxide bonded silicon carbide or corderite. Right now I have these shelves=
=3D
in the rafters with the 16,000Btu. Timken oil furnace blowing on them for =
=3D
a week or so and I might put one in the oven for an hour or two at 200 just=
=3D
to be certain before loading more. Then I will per-heat with the pignose a=
=3D
t below 200=3DBAF for a day to start the bisque part of the once-fire load.=
I=3D
hope this is enough to keep mine from exploding. I could skip it and just =
=3D
get by with a few shelves short of a full load or maybe tumble stack
some if I can remember how to make interesting blemish spots where the pot=
=3D
s stick together. =3D0A=3D0AGary Navarre=3D0ANavarre Pottery=3D0ANavarre E=
nterpris=3D
es=3D0ANorway, Michigan, USA=3D0Ahttp://www.youtube.com/GindaUP=3D0Ahttp://=
public=3D
.fotki.com/GindaUP/=3D0A=3D0A=3D0A--- On Mon, 12/21/09, Larry Kruzan _kruza=3D
n@COMCAST.NET> wrote:=3D0A=3D0A> From: Larry Kruzan ET>=3D
=3D0A> Subject: Re: [Clayart] Wet sanding corderite kiln shelves and yellow=
s=3D
tain afterwards=3D0A> To: Clayart@LSV.CERAMICS.ORG=3D0A> Date: Monday, Dece=
mber=3D
21, 2009, 8:54 PM=3D0A> Hi Edward,=3D0A> A few questions about this. How l=
ong =3D
does it take for the=3D0A> shelves to dry=3D0A> enough to use? Have you had=
any=3D
issues with shelves blowing=3D0A> up in the kiln=3D0A> after they were wet=
san=3D
ded? =3D0A =3D0A> All IMHO=3D0A> Larry Kruzan=3D0A> Lost Creek Pottery=3D0A=
> www.lost=3D
creekpottery.com=3D0A> =3D0A> =3D0A> =3D0A> -----Original Message-----=3D0A=
> From: Cl=3D
ayart [mailto:Clayart@LSV.CERAMICS.ORG]=3D0A> On Behalf Of Edward Huml=3D0A=
> Se=3D
nt: Monday, December 21, 2009 2:56 PM=3D0A> To: Clayart@LSV.CERAMICS.ORG=3D=
0A> =3D
Subject: Wet sanding corderite kiln shelves and yellow=3D0A> stain afterwar=
ds=3D
=3D0A> =3D0A> After trying to clean off our electric kiln corderite=3D0A> s=
helves=3D
by various=3D0A> dry, dusty methods I have used a wet sanding procedure to=
=3D
=3D0A> clean a couple.=3DA0=3D0A> My question is: any problem with using th=
em in =3D
the kiln=3D0A> after drying them=3D0A> well? When the last one was dried on=
top=3D
of a kiln firing=3D0A> it had a yellow=3D0A> stain on the bottom. I can't =
thin=3D
k of any reason but=3D0A> figured I would ask=3D0A> first.=3D0A=3D0A> Thank=
s,Ed Hum=3D
l=3D0A> =3D0A=3D0A=3D0A
Edward Huml on mon 21 dec 09
After trying to clean off our electric kiln corderite shelves by various dr=
=3D
y, dusty methods I have used a wet sanding procedure to clean a couple.=3DA=
0
My question is: any problem with using them in the kiln after drying them w=
=3D
ell? When the last one was dried on top of a kiln firing it had a yellow st=
=3D
ain on the bottom. I can't think of any reason but figured I would ask firs=
=3D
t.
My procedure: I have found a Makita GV5000 disc sander, variable speed, and=
=3D
5 inch wet/dry 36 grit sanding discs work like a dream. What I do now is s=
=3D
et the shelf to be cleaned on top of the sink, angling down a bit to drain =
=3D
the water into the sink. After trying to splash water from the faucet by ha=
=3D
nd I now use a plastic quart yogurt container with three closely spaced pin=
=3D
tool holes near the bottom to flow a small amount of water on the shelf wh=
=3D
ile I use the disc sander on a slow speed. (Still need to wear a waterproof=
=3D
apron and hearing protectors though.) The sander is plugged in a GFCI outl=
=3D
et just to be sure.
This seems to do the trick calmly, cleanly and fairly quickly. Inspired by =
=3D
the diamond disc used with a water drip by the crystal glaze folks and usin=
=3D
g the wet grinder for woodworking in the studio I was determined to find a =
=3D
safe way not to create so much dust I would have to hose myself off before =
=3D
returning indoors.
The setup cost under $100 at Home Depot. You could probably do better on th=
=3D
e internet, I wasn't willing to wait with so many unusable shelves.
Thanks,Ed Huml
=3D0A=3D0A=3D0A
William & Susan Schran User on mon 21 dec 09
On 12/21/09 3:56 PM, "Edward Huml" wrote:
> After trying to clean off our electric kiln corderite shelves by various =
=3D
dry,
> dusty methods I have used a wet sanding procedure to clean a couple.=3DA0
> My question is: any problem with using them in the kiln after drying them
> well? When the last one was dried on top of a kiln firing it had a yellow
> stain on the bottom. I can't think of any reason but figured I would ask
> first.
Yellow stain my simply be from minerals in the water.
I would suggest you stack the shelves vertically or as normal on posts and
do a very slow firing to red heat to drive all of the water out.
Bill
--=3D20
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Snail Scott on mon 21 dec 09
> On 12/21/09 3:56 PM, "Edward Huml" wrote:
>> ...trying to clean off our electric kiln corderite shelves...When the
>> last one was dried on top of a kiln firing it had a yellow stain on
>> the bottom...
Almost certainly some efflorescence from soluble
minerals (salts or some such) in your water. It
happens. It's unlikely to have enough density to
affect your shelves, but if you are worried, wet
them again and let them dry as evenly as possible.
These efflorescence deposits accumulate in the
places that the water wicks them to. An even drying
pattern will ensure an even, low-density distribution.
(For instance, wrap the edges lightly, and dry them
where they'll get air to both sides.) Personally, I
wouldn't bother unless you routinely fire your
shelves to the limit of their endurance.
-Snail
Larry Kruzan on mon 21 dec 09
Hi Edward,
A few questions about this. How long does it take for the shelves to dry
enough to use? Have you had any issues with shelves blowing up in the =3D
kiln
after they were wet sanded?=3D20
As you might expect some may wonder about the wisdom of using a electric
grinder in a wet sanding application. You did state that you are using a =
=3D
GFI
circuit, so I hope that your grinders plug has a ground post. This is
required for a GFI to function properly. I have several hand grinders in =
=3D
my
welding shop that do not have this critical ground post. They all are =3D
sold
as "isolated" because they have a plastic housing. With this sort of =3D
housing
the electrical code does not require a ground wire since there is no =3D
metal
case to come into contact with. However, dousing the housing with water =3D
will
allow it to conduct voltage - this can, and has lead to shocks.
I honestly do not know how much you can get away with here but I know =3D
that
if OSHA ever saw this I am dead certain how the engineers there would =3D
see
it. My son is a pipeliner and works in wet conditions welding every day =3D
-
you would not believe how regulated they are about this sort of thing. =3D
His
solution is to use a pneumatic powered grinder since his welding rig has =
=3D
a
big compressor on it. It got so tough last year that the general =3D
contractor
finally banned the use of ungrounded electric grinders rather than fight
with OSHA.
All IMHO
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Edward Huml
Sent: Monday, December 21, 2009 2:56 PM
To: Clayart@LSV.CERAMICS.ORG
Subject: Wet sanding corderite kiln shelves and yellow stain afterwards
After trying to clean off our electric kiln corderite shelves by various
dry, dusty methods I have used a wet sanding procedure to clean a =3D
couple.=3DA0
My question is: any problem with using them in the kiln after drying =3D
them
well? When the last one was dried on top of a kiln firing it had a =3D
yellow
stain on the bottom. I can't think of any reason but figured I would ask
first.
My procedure: I have found a Makita GV5000 disc sander, variable speed, =3D
and
5 inch wet/dry 36 grit sanding discs work like a dream. What I do now is =
=3D
set
the shelf to be cleaned on top of the sink, angling down a bit to drain =3D
the
water into the sink. After trying to splash water from the faucet by =3D
hand I
now use a plastic quart yogurt container with three closely spaced pin =3D
tool
holes near the bottom to flow a small amount of water on the shelf while =
=3D
I
use the disc sander on a slow speed. (Still need to wear a waterproof =3D
apron
and hearing protectors though.) The sander is plugged in a GFCI outlet =3D
just
to be sure.
This seems to do the trick calmly, cleanly and fairly quickly. Inspired =3D
by
the diamond disc used with a water drip by the crystal glaze folks and =3D
using
the wet grinder for woodworking in the studio I was determined to find a
safe way not to create so much dust I would have to hose myself off =3D
before
returning indoors.
The setup cost under $100 at Home Depot. You could probably do better on =
=3D
the
internet, I wasn't willing to wait with so many unusable shelves.
Thanks,Ed Huml
John Post on tue 22 dec 09
Larry,
I have not wet ground shelves this way, but I have cut corderite
shelves down using a wet tile saw from Home Depot. I did this so I
could use some large free ones I was given with a smaller kiln.
The shelves get totally wet from the wet saw. In the summer, I just
let them dry outside in the sun for a week or so.
What I would do if it wasn't summer would be to place them in a kiln
and if you have a computer controller hold them at 185 degrees
Fahrenheit for several hours until you felt all the moisture was out
of them. Steam forms at 212 degrees Fahrenheit, so holding it a
temperature lower than that will drive out the moisture without
creating an exploding or cracking shelf.
The yellow stains are from minerals in the water and will just
disappear when you fire the shelves.
John Post
Sterling Heights, Michigan
:: cone 6 glaze website :: http://www.johnpost.us
:: elementary art website :: http://www.wemakeart.org
On Dec 21, 2009, at 9:54 PM, Larry Kruzan wrote:
> Hi Edward,
> A few questions about this. How long does it take for the shelves to
> dry
> enough to use? Have you had any issues with shelves blowing up in
> the kiln
> after they were wet sanded?
>
> As you might expect some may wonder about the wisdom of using a
> electric
> grinder in a wet sanding application. You did state that you are
> using a GFI
> circuit, so I hope that your grinders plug has a ground post. This is
> required for a GFI to function properly. I have several hand
> grinders in my
> welding shop that do not have this critical ground post. They all
> are sold
> as "isolated" because they have a plastic housing. With this sort of
> housing
> the electrical code does not require a ground wire since there is no
> metal
> case to come into contact with. However, dousing the housing with
> water will
> allow it to conduct voltage - this can, and has lead to shocks.
>
> I honestly do not know how much you can get away with here but I
> know that
> if OSHA ever saw this I am dead certain how the engineers there
> would see
> it. My son is a pipeliner and works in wet conditions welding every
> day -
> you would not believe how regulated they are about this sort of
> thing. His
> solution is to use a pneumatic powered grinder since his welding rig
> has a
> big compressor on it. It got so tough last year that the general
> contractor
> finally banned the use of ungrounded electric grinders rather than
> fight
> with OSHA.
>
> All IMHO
> Larry Kruzan
> Lost Creek Pottery
> www.lostcreekpottery.com
>
>
>
> -----Original Message-----
> From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Edward
> Huml
> Sent: Monday, December 21, 2009 2:56 PM
> To: Clayart@LSV.CERAMICS.ORG
> Subject: Wet sanding corderite kiln shelves and yellow stain
> afterwards
>
> After trying to clean off our electric kiln corderite shelves by
> various
> dry, dusty methods I have used a wet sanding procedure to clean a
> couple.
> My question is: any problem with using them in the kiln after drying
> them
> well? When the last one was dried on top of a kiln firing it had a
> yellow
> stain on the bottom. I can't think of any reason but figured I would
> ask
> first.
> My procedure: I have found a Makita GV5000 disc sander, variable
> speed, and
> 5 inch wet/dry 36 grit sanding discs work like a dream. What I do
> now is set
> the shelf to be cleaned on top of the sink, angling down a bit to
> drain the
> water into the sink. After trying to splash water from the faucet by
> hand I
> now use a plastic quart yogurt container with three closely spaced
> pin tool
> holes near the bottom to flow a small amount of water on the shelf
> while I
> use the disc sander on a slow speed. (Still need to wear a
> waterproof apron
> and hearing protectors though.) The sander is plugged in a GFCI
> outlet just
> to be sure.
> This seems to do the trick calmly, cleanly and fairly quickly.
> Inspired by
> the diamond disc used with a water drip by the crystal glaze folks
> and using
> the wet grinder for woodworking in the studio I was determined to
> find a
> safe way not to create so much dust I would have to hose myself off
> before
> returning indoors.
> The setup cost under $100 at Home Depot. You could probably do
> better on the
> internet, I wasn't willing to wait with so many unusable shelves.
> Thanks,Ed Huml
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