Dave Gayman on tue 5 feb 02
Getting back into clay -- in the 1970s I used the drop-down, cone-hat type
of kiln vent. It was none too effective for the organic- and sulfur-laden
clays I was using then.
Are the draw-off-the-bottom type more effective? What's been your experience?
I'll be firing in a basement. I could wall off a tiny kiln room and
control ventilation, but would rather not.
Dave
william schran on tue 5 feb 02
Dave - I also work in a basement and had a drop down kiln vent that
didn't vent very well and would get too hot and shut off - lotta good
that did!
Got vent system from Bailey. Downdraft system. drill small hole in
side of kiln near bottom, leave out top spy hole plug. Motor is
mounted away from kiln. Works very well.
Bill
vince pitelka on tue 5 feb 02
> Dave - I also work in a basement and had a drop down kiln vent that
> didn't vent very well and would get too hot and shut off - lotta good
> that did!
> Got vent system from Bailey. Downdraft system. drill small hole in
> side of kiln near bottom, leave out top spy hole plug. Motor is
> mounted away from kiln. Works very well.
I appologize in advance to the makers of the drop-down kiln vent hood, but
those systems are pretty much worthless. This has been stated numerous
times before on Clayart. An electric kiln does not develop enough exterior
heat to develop a significant current of upward moving air, and an overhead
hood accomplishes nothing at all without that consistent upward current.
Whatever upward current of warm air there might be around an electric kiln
is so mild that it is disturbed by the slightest air movement from central
heat/air, someone walking past, an open door or window, etc., and then the
hood is not doing a damn thing. The only electric kiln vent systems worth a
damn are the negative pressure direct hookup models like the Bailey, Skutt,
and others.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Jim Mason on tue 5 feb 02
Dave,
I am very pleased with the Envirovent that I installed on my used Skutt 1027.
Five small holes are drilled in the lid about 2 inches in from the Kiln wall,
and five small holes within a 3 inch circle in the middle of the bottom. The
fan pulls fumes from the kiln and mixes it with much more "room air" and all
is vented outside.
Hope this helps,
Jim Mason,
Gibsonville, NC
Diane Palmquist on tue 5 feb 02
Can I ask does this change the temp. in your kiln at all especially in
the bottom?
Thanks- Diane
----- Original Message -----
From: "william schran"
To:
Sent: Tuesday, February 05, 2002 5:23 PM
Subject: Re: Electic kiln vents
> Dave - I also work in a basement and had a drop down kiln vent that
> didn't vent very well and would get too hot and shut off - lotta good
> that did!
> Got vent system from Bailey. Downdraft system. drill small hole in
> side of kiln near bottom, leave out top spy hole plug. Motor is
> mounted away from kiln. Works very well.
> Bill
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
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>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
>
Frederich, Tim on wed 6 feb 02
Diane,
A downdraft vent system will usually even out the kiln bringing heat from
the top (where it naturally rises) to the bottom. If it is installed
properly, it will not extend the firing time because it is drawing a minimal
amount of air through the kiln.
Best regards,
Tim Frederich
-----Original Message-----
From: Diane Palmquist [mailto:dlpots@SNET.NET]
Sent: Tuesday, February 05, 2002 7:22 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Electic kiln vents
Can I ask does this change the temp. in your kiln at all especially in
the bottom?
Thanks- Diane
----- Original Message -----
From: "william schran"
To:
Sent: Tuesday, February 05, 2002 5:23 PM
Subject: Re: Electic kiln vents
> Dave - I also work in a basement and had a drop down kiln vent that
> didn't vent very well and would get too hot and shut off - lotta good
> that did!
> Got vent system from Bailey. Downdraft system. drill small hole in
> side of kiln near bottom, leave out top spy hole plug. Motor is
> mounted away from kiln. Works very well.
> 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.
>
>
____________________________________________________________________________
__
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.
william schran on thu 7 feb 02
Diane - Doesn't seem to. Actually looks to have evened out the
temperature throughout the kiln. Had cone packs at each level and
they were fairly consistent.
Bill
Stephen J Lewicki on fri 8 feb 02
A couple of comments for the record about kiln vents in no particular order:
The Orton patented method of downdraft venting is definitely superior to
the hood vents. Orton of course makes this, Skutt licenses it as do we
(L&L) and I believe Bailey.
Only Bailey and L&L keep the motor away from the kiln bottom (it is
mounbted n the wall). This does three important things. First of all it
keeps the poisonous air under vacuum instead of pressure. If there is a
leak in your duct (very likely) the bad air won't blow into your room.
Second it keeps the motor away from the heat of the kiln. The motor will
last longer. In fact, we have rarely had to replace motors either under
warranty or post warranty. Another advantage of this concept is that you
can turn off the vent if you want to while the kiln is hot. I believe Orton
and Skutt recommend against this because you have to have cooling air on
their bottom mounted motors. Third, the motor's vibration will not affect
the kiln or cones or Dawson, etc. The vibrations could cause the cone in
the Dawson to come loose and misfire.
Our vent system (the L&L Vent-Sure) has what we call a by-pass valve which
allows you to adjust the amount of venting that you pull from your kiln.
This is important. I had to troubleshoot one of our kilns a few years back
that could come to temperature. It turns out (after painstaking
questioning) that they had a Skutt Envirovent that was way overpowered for
the small kiln. Driling more holes or plugging them up seems like a crude
way to make adjustments.
Another consideration about using Orton or Envirovent systems on other
kilns is that you really must be careful of the size of the stand they
provide. I have seen some large L&L kilns sitting on tiny stands - a
situation that invites the bottom to crack.
One thing I have never been totally comfortable with is the recommendations
from Orton and others for drilling holes in the kiln top. We normaly do not
recommend it - but primerily because I feel it weakens the already fragile
top. electric kilns are not that tight and it seems there is plenty of ways
for the air to get into the kiln. However, this does seem to vary in
certain situations and we tell people to do this if they aren't getting
good ventilation. If you do it be sure to put the holes (like Orton says)
around the perimeter of the oodr. I have heard of center holes in the top
really creating a cold spot in the top middle. I would be interested in
hearing comments on people's experience with this. I am struggling with
exactly what to tell people in our instructions.
Another thoguht - buy a CO detector (they are cheap) and install it in your
kiln room.
Stephen J Lewicki
President, L&L Kiln Mfg.
william schran on fri 8 feb 02
>Stephen - You wrote:
>"One thing I have never been totally comfortable with is the recommendations
>from Orton and others for drilling holes in the kiln top. We normaly do not
>recommend it - but primerily because I feel it weakens the already fragile
>top. electric kilns are not that tight and it seems there is plenty of ways
>for the air to get into the kiln."
I totally agree. I would add: don't drill any holes in the bottom
either. I'm sure the holes down there could also invite problems.
I debated between the vent from L&L and the one from Bailey. Went
with Bailey for purely economic reasons. One small hole through the
side wall of bottom ring and leave out top spy hole plug - that's it.
As I said in previous message, I seem to get fairly even temp top to
bottom and the thing actually works.
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.
BeardiePaw on fri 8 feb 02
Hi, I have a kiln vent on my Cress kiln. Two small holes in the top and
two in the bottom. I seem to get really good flow with it, I do turn it off
at the end of the firing, and have never had problems. Husband tested it
when we put it in and no Carbon monoxide. It does not make a cold spot on
the top of the kiln, rather, if I put a third shelf in the top, it is hotter
there by one cone, but it is cooler on the bottom. I've learned how to
control the heat during firing, by cone packs which helped me see what was
really going on in there. Sherry Morrow
Susan on mon 11 feb 02
I am curious about the by-pass valve feature on the Vent-Sure vents from
L&L. I just purchased one along with my L&L kiln and wonder from other
clayart readers how open they keep this valve hole? Would one change it for
bisque and glaze or leave it the same? I read the manual and it didn't go
into any detail about how open the hole should be...just that the more you
keep the hole open the less the vent will be efficient in sucking out the
gases. I am guessing that if I do china painting and decals I would close
the opening hole completely...but what about normal day to day bisque and
glazing?
and do you shut off the fan after a certain temperature?
Susan
> From: Stephen J Lewicki
> Reply-To: Ceramic Arts Discussion List
> Date: Fri, 8 Feb 2002 09:22:10 -0500
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Electic kiln vents
>
>
> Our vent system (the L&L Vent-Sure) has what we call a by-pass valve which
> allows you to adjust the amount of venting that you pull from your kiln.
> This is important.
>
> Stephen J Lewicki
> President, L&L Kiln Mfg.
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