William & Susan Schran User on fri 10 mar 06
On 3/10/06 11:12 AM, "LindaC" wrote:
> good to have a vent with
> motor mounted away from the kiln to avoid vibration
> ...is this true and what does a little vibration do?
I think the issue anymore is not so much a vibration problem,
but rather having the motor overheat or wear out faster due to heat issues.
There is also an issue in creating negative pressure in the vent system, so
there is less of a chance of fumes leaking into the room instead of being
exhausted out.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
Mayssan Shora Farra on fri 10 mar 06
Hello Linda:
The problem with bottom mounted fans like the Envirovent is not limited to
vibration, it also applies positive air pressure through the duct making
it possible for gasses to get into the studio if any holes are in the duct.
Also according to their instructions you do have to keep it on till the
kiln cools down sufficiently otherwise it can be ruined since air cools it
while it is running and it gets too hot if it stops.
I used to have one on my old kiln and switched to the wall mounted one
with double ducts for both kilns and it did cut down on the smells coming
from the kiln.
Mayssan
In springlike Charleston WV USA
LindaC on fri 10 mar 06
I've got bottom mounted vents on both my electric
kilns and have heard its good to have a vent with
motor mounted away from the kiln to avoid vibration
...is this true and what does a little vibration do?
Also is it ok to switch off the vent right away at the
end of the firing because it would seem that the fan
would cause faster cooling and I want to soak for a
short time. Any input appreciated.
William Melstrom on fri 10 mar 06
Linda, during the several hours that a firing can take, vibration can cause
ware and cones to move around and end up kissing each other. There was a
period when I lost a couple of pieces, worth a couple of hundred dollars,
during every firing because of this. Pieces would even walk all the way off
of the edges of my shelves.
It is really easy to convert your bottom-mounted fan to a wall mounted one.
You already have a hole in your wall, which means that you have already done
the hard work. And you already have a diffuser box, ducting, and air inlet
holes drilled in your kiln. All you need to do is remove the fan and motor,
re-mount them on the wall, and buy and connect appropriate transitional
ductwork.
Regarding turning off the vent right at the end of your firing, this is one
more reason to move your fan motor. But, if you don't, I think you will be
okay, especially if you fire below cone 10.
I wrote an unfinished article with pictures about making your own non
kiln-mounted vent that you might find useful at:
http://www.handspiral.com/kiln_vent.htm
Good luck,
William Melstrom
----- Original Message -----
From: "LindaC"
To:
Sent: Friday, March 10, 2006 10:12 AM
Subject: Question on kiln vent
> I've got bottom mounted vents on both my electric
> kilns and have heard its good to have a vent with
> motor mounted away from the kiln to avoid vibration
> ...is this true and what does a little vibration do?
> Also is it ok to switch off the vent right away at the
> end of the firing because it would seem that the fan
> would cause faster cooling and I want to soak for a
> short time. Any input appreciated.
>
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Mark Tigges on fri 10 mar 06
On Fri, Mar 10, 2006 at 11:12:34AM -0500, LindaC wrote:
> I've got bottom mounted vents on both my electric
> kilns and have heard its good to have a vent with
> motor mounted away from the kiln to avoid vibration
> ...is this true and what does a little vibration do?
> Also is it ok to switch off the vent right away at the
> end of the firing because it would seem that the fan
> would cause faster cooling and I want to soak for a
> short time. Any input appreciated.
>
There are other better reasons to have it away from the kiln. If the
motor is attached to the wall then the ducting that is in the room is
all under a negative pressure gradient compared to the room. So that
means that if there are any leaks in the ducting then no noxious gas
will leak into the room. Second the air passing through the fan is
not as caustic and damaging to the fan.
I don't think either of those reasons is compelling enough to switch
given that you already have a venting solution in place. Although, you
could yourself fabricate a system for next to nothing given the fan
and ducting that you already have.
Having the fan on during the soak is not an issue, I recently added a
fan to my kiln, and the difference in power required is not noticeable
at top temperature. For the cool cycle, I always fire down, so I
leave the fan on then too.
Mark.
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