Arnold Howard on tue 24 may 05
A couple of reasons to leave the downdraft vent running during cooling: If
you turn the KilnVent off when the kiln fires to maturity, moisture can
build up inside the Kiln Sitter tube as the kiln cools. Gases may also
condense on the vent motor, causing excessive corrosion.
From the shut-off temperature down to 1000 degrees F, the Orton KilnVent has
little effect on cooling time. From 1000 degrees F to room temperature, it
reduces cooling time by about two hours. (This is what people at Orton have
told me.) Other brands of downdraft vents probably affect cooling time the
same.
Slow cooling gives the micro-crystalline structure of certain glazes extra
time for full development. People on Clayart swear by it. On the other hand,
some people want fast cooling so they can reload the kiln every 24 hours.
There are many different firing schedules for crystalline glazes depending
on the type of glaze you are using. You will find firing schedules in
"Crystalline Glazes," by Diane Creber. I'm sure many people on this list
fire crystalline glazes, too.
You can cool slowly with a manual-fire kiln. After the Kiln Sitter shuts
off, turn off the kiln switches. Then raise the weight, press in the Kiln
Sitter plunger, and gently lower the weight. Make sure the Limit Timer has
enough time on the clock for your slow cooling. (Caution: The above
procedure will place the Kiln Sitter on manual, so it will no longer shut
off the kiln.)
Then turn the kiln switches to medium. (It would be very helpful to have a
pyrometer for precise controlled cooling. Otherwise you will need to
experiment with the kiln's switch settings.)
With a digital kiln, you may have a Slow Cool option in Cone-Fire mode.
(During Cone-Fire programming, Paragon's Sentry controller flashes COOL
after the Hold time. To do a slow cooling, enter the cooling rate in degrees
per hour. The newest Bartlett controller used in Skutt kilns also has a type
of Slow Cool option.)
To do a slow cooling in Ramp-Hold mode, add a slow cooling segment to the
firing schedule. Most controllers will automatically do a slow cooling if
the segment temperature is lower than that of the previous segment.
If anyone is confused about digital controllers, please let me know. I'll be
glad to help.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net / www.paragonweb.com
From: "roxanne hunnicutt" <555jesswein@CHARTER.NET>
> "I suggest leaving the vent on throughout the cooling. Turn it off when
> you
> unload the kiln.
> Sincerely, Arnold Howard, Paragon Industries, L.P., Mesquite, Texas...."
>
> Mr. Howard,
>
> Why would one leave the vent on during cooling? Isn't slow cooling almost
> always preferable. When is fast cooling helpful?
>
> And can you send me to some directions for firing down, or really slow
> cooling and tell me what that would be helpful for? It is helpful for
> crystals, isn't it?]
Eric Serritella on wed 25 may 05
I also remember reading in the Orton instructions once that the heat of the
kiln would damage the vent unless it was on, so this is another reason to
keep it going at all times. This is not true of the Bailey vent, as the
fan/motor does not sit under the kiln. I'd suggest this vent if you have a
need to shut it during cooling.
Eric
Muddy Paws Pottery
528 Sebring Road
Newfield, NY 14867
607.564.7810
www.muddypawspottery.com
----- Original Message -----
From: "Arnold Howard"
To:
Sent: Tuesday, May 24, 2005 10:32 AM
Subject: Running the vent motor during cooling
> A couple of reasons to leave the downdraft vent running during cooling: If
> you turn the KilnVent off when the kiln fires to maturity, moisture can
> build up inside the Kiln Sitter tube as the kiln cools. Gases may also
> condense on the vent motor, causing excessive corrosion.
>
> >From the shut-off temperature down to 1000 degrees F, the Orton KilnVent
has
> little effect on cooling time. From 1000 degrees F to room temperature, it
> reduces cooling time by about two hours. (This is what people at Orton
have
> told me.) Other brands of downdraft vents probably affect cooling time the
> same.
>
>
>
> Slow cooling gives the micro-crystalline structure of certain glazes extra
> time for full development. People on Clayart swear by it. On the other
hand,
> some people want fast cooling so they can reload the kiln every 24 hours.
>
>
>
> There are many different firing schedules for crystalline glazes depending
> on the type of glaze you are using. You will find firing schedules in
> "Crystalline Glazes," by Diane Creber. I'm sure many people on this list
> fire crystalline glazes, too.
>
>
>
> You can cool slowly with a manual-fire kiln. After the Kiln Sitter shuts
> off, turn off the kiln switches. Then raise the weight, press in the Kiln
> Sitter plunger, and gently lower the weight. Make sure the Limit Timer has
> enough time on the clock for your slow cooling. (Caution: The above
> procedure will place the Kiln Sitter on manual, so it will no longer shut
> off the kiln.)
>
>
>
> Then turn the kiln switches to medium. (It would be very helpful to have a
> pyrometer for precise controlled cooling. Otherwise you will need to
> experiment with the kiln's switch settings.)
>
>
>
> With a digital kiln, you may have a Slow Cool option in Cone-Fire mode.
> (During Cone-Fire programming, Paragon's Sentry controller flashes COOL
> after the Hold time. To do a slow cooling, enter the cooling rate in
degrees
> per hour. The newest Bartlett controller used in Skutt kilns also has a
type
> of Slow Cool option.)
>
>
>
> To do a slow cooling in Ramp-Hold mode, add a slow cooling segment to the
> firing schedule. Most controllers will automatically do a slow cooling if
> the segment temperature is lower than that of the previous segment.
>
>
>
> If anyone is confused about digital controllers, please let me know. I'll
be
> glad to help.
>
>
>
> Sincerely,
>
>
>
> Arnold Howard
>
> Paragon Industries, L.P., Mesquite, Texas USA
>
> arnoldhoward@att.net / www.paragonweb.com
>
>
>
> From: "roxanne hunnicutt" <555jesswein@CHARTER.NET>
> > "I suggest leaving the vent on throughout the cooling. Turn it off when
> > you
> > unload the kiln.
> > Sincerely, Arnold Howard, Paragon Industries, L.P., Mesquite, Texas...."
> >
> > Mr. Howard,
> >
> > Why would one leave the vent on during cooling? Isn't slow cooling
almost
> > always preferable. When is fast cooling helpful?
> >
> > And can you send me to some directions for firing down, or really slow
> > cooling and tell me what that would be helpful for? It is helpful for
> > crystals, isn't it?]
>
>
____________________________________________________________________________
__
> 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.
>
Arnold Howard on fri 27 may 05
Orton's new Master Vent is mounted away from the kiln. Orton has
discontinued the KilnVent series, which mount either under or on the side of
the kiln. I think all the downdraft vent systems are moving in the direction
of the Bailey vent, which pulls instead of pushes the air from the kiln.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net / www.paragonweb.com
----- Original Message -----
From: "Eric Serritella"
>I also remember reading in the Orton instructions once that the heat of the
> kiln would damage the vent unless it was on, so this is another reason to
> keep it going at all times. This is not true of the Bailey vent, as the
> fan/motor does not sit under the kiln. I'd suggest this vent if you have a
> need to shut it during cooling.
| |
|
