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silica sand use and down draft vent

updated tue 17 may 05

 

Debbie White on sat 14 may 05


Hello everyone,
I am just getting use to using a Bailey Down Draft Vent on my electric kiln.
I use kiln wash on my shelves...but occasionally I sprinkle a little bit of
fine silica sand on a kiln shelf if I have a pot ..e.g.. a lid for my butter
dishes that I do not want to warp. I am becoming suspect that maybe the
silica sand may be flying around in the kiln during firing because of the
down draft air movement effects and landing on other pots.

Is this a possibility?......am I courting disaster?...and should stop using
the silica sand?

Just wondering!


Debbie White
Wolverton Hills
www.wolvertonhills.com

Maurice Weitman on sat 14 may 05


Hi, Debbie,

In my experience with Bailey vents, when set up properly they don't
move enough air to blow sand around. MAYBE move it slightly, but I
doubt even that. Powder might be able to be moved, but only if it
were quite near to the kiln exit hole (is it 3/8"?) or a smaller
air-entry hole.

What kink of kiln are you using and how does "make-up" air get into the kiln?

The Bailey instructions I've seen call for the top peep to remain
open. I've recently been trying to find another way, like drilling
holes in the top. Several clayarters have tried to dissuade me.
We'll see.

The mounting instructions call for space between the duct flange and
the kiln to add cool air to the duct and moderate the flow of air
through the kiln. This should suffice to prevent the kind of suction
force that would result in fine sand to move around.

To prove it to yourself (and the rest of us when you report your
results - heh!), put a thin layer of fine sand on a shelf near the
peep and rake some sharp lines in the sand perpendicular to the flow
of air, close the lid, open the peep and turn on the vent for a
couple of hours. Certainly things would be different when the kiln
is very hot, but I believe at that heat, the air flow would be
reduced and become less of a problem.

Regards,
Maurice


At 9:32 AM -0400 on 5/14/05, Debbie White wrote:
>Hello everyone,
>I am just getting use to using a Bailey Down Draft Vent on my electric kiln.
>I use kiln wash on my shelves...but occasionally I sprinkle a little bit of
>fine silica sand on a kiln shelf if I have a pot ..e.g.. a lid for my butter
>dishes that I do not want to warp. I am becoming suspect that maybe the
>silica sand may be flying around in the kiln during firing because of the
>down draft air movement effects and landing on other pots.
>
>Is this a possibility?......am I courting disaster?...and should stop using
>the silica sand?

william schran on sat 14 may 05


Maurice wrote:>The Bailey instructions I've seen call for the top
peep to remain
open. I've recently been trying to find another way, like drilling
holes in the top. Several clayarters have tried to dissuade me.<

Ok Maurice, here's another clayarter dissuading you from drilling
holes in the top of your kiln.
Why don't you want to leave the top spy hole plug out?
I have a Bailey vent, I leave to top plug out, I get very even
firings (top to bottom).

L&L vent systems suggest that there's enough gaps between lid and
wall and between sections, that sufficient air will be drawn in
through these areas and spy hole plugs can be left in.

Bill

Marcia Selsor on sat 14 may 05


Silica sand can fly around and get onto glazed surfaces. If your
shelves are smooth, try mixing some alumina with your wax. I think it
has enough gritty powder to alllow movement of the shrinking lips/
feet. Make sure you have smooth shelves.
Good luck,
Marcia Selsor
On May 14, 2005, at 7:32 AM, Debbie White wrote:

> Hello everyone,
> I am just getting use to using a Bailey Down Draft Vent on my
> electric kiln.
> I use kiln wash on my shelves...but occasionally I sprinkle a
> little bit of
> fine silica sand on a kiln shelf if I have a pot ..e.g.. a lid for
> my butter
> dishes that I do not want to warp. I am becoming suspect that
> maybe the
> silica sand may be flying around in the kiln during firing because
> of the
> down draft air movement effects and landing on other pots.
>
> Is this a possibility?......am I courting disaster?...and should
> stop using
> the silica sand?
>
> Just wondering!
>
>
> Debbie White
> Wolverton Hills
> www.wolvertonhills.com
>
> ________

Marcia Selsor on sun 15 may 05


I have a Bailey downdraft gas kiln. I misunderstood the situation
On May 14, 2005, at 10:26 PM, Maurice Weitman wrote:

> At 9:16 PM -0600 on 5/14/05, Marcia Selsor wrote:
>
>> Silica sand can fly around and get onto glazed surfaces. If your
>> shelves are smooth, try mixing some alumina with your wax. I think it
>> has enough gritty powder to alllow movement of the shrinking lips/
>> feet. Make sure you have smooth shelves.
>>
>
> Hi, Marcia,
>
> Are you saying that the silica sand will blow around in an electric
> kiln?
>
> I've never seen that happen. Maybe in a gas or wood-fired kiln.
>
> Regards,
> Maurice
>
>

Louis Katz on sun 15 may 05


That vent does not have enough blow when installed according to
directions to blow anything. Vibrations may be another thing.
Despite everything the sand is likely to get everywhere unless you have
that sort of extreme care everytime personality that can keep it from
spilling and far from the edges. I like t limit use of sand in glaze
firings to the bottom shelves.
Louis
On May 14, 2005, at 8:32 AM, Debbie White wrote:

> Hello everyone,
> I am just getting use to using a Bailey Down Draft Vent on my electric
> kiln.
> I use kiln wash on my shelves...but occasionally I sprinkle a little
> bit of
> fine silica sand on a kiln shelf if I have a pot ..e.g.. a lid for my
> butter
> dishes that I do not want to warp. I am becoming suspect that maybe
> the
> silica sand may be flying around in the kiln during firing because of
> the
> down draft air movement effects and landing on other pots.
>
> Is this a possibility?......am I courting disaster?...and should stop
> using
> the silica sand?
>
> Just wondering!
>
>
> Debbie White
> Wolverton Hills
> www.wolvertonhills.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.
>

Debbie White on sun 15 may 05


I'm not sure what mesh the silica sand is I am using....other than it is
very fine..It came with a kiln I bought. However, from most responses to
this topic......silica should not move around in an electric kiln with a
down draft. My kiln wash on my shelves is 80% alumina and 20% China Clay.
I only used the sand as an added precaution from warping. I think maybe I
will try to add alumina to my wax resist as suggested.....it would be less
messy than using sand in the kiln.

Thanx for your responses.

Cheers,
Debbie White
www.wolvertonhills.com

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Marcia
Selsor
Sent: May 15, 2005 3:04 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Silica Sand use and Down Draft Vent


I have a Bailey downdraft gas kiln. I misunderstood the situation
On May 14, 2005, at 10:26 PM, Maurice Weitman wrote:

> At 9:16 PM -0600 on 5/14/05, Marcia Selsor wrote:
>
>> Silica sand can fly around and get onto glazed surfaces. If your
>> shelves are smooth, try mixing some alumina with your wax. I think it
>> has enough gritty powder to alllow movement of the shrinking lips/
>> feet. Make sure you have smooth shelves.
>>
>
> Hi, Marcia,
>
> Are you saying that the silica sand will blow around in an electric
> kiln?
>
> I've never seen that happen. Maybe in a gas or wood-fired kiln.
>
> Regards,
> Maurice
>
>

____________________________________________________________________________
__
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.

Des & Jan Howard on sun 15 may 05


Debbie
We use forced air burners & spreading loose sand on shelves would just
contribute greatly to kiln crap. Our shelf wash is 95% zircon flour/ 5%
kaolin. All bell dish lids (75mm, 160mm,183mm & 220mm biscuited) are
fired on 5 mm cookies made from the same clay as the pot, washed with
shelf wash & discarded after one use. Warpages zero.
Des

Debbie White wrote:

>I am just getting use to using a Bailey Down Draft Vent on my electric kiln.
>I use kiln wash on my shelves...but occasionally I sprinkle a little bit of
>fine silica sand on a kiln shelf if I have a pot ..e.g.. a lid for my butter
>dishes that I do not want to warp. I am becoming suspect that maybe the
>silica sand may be flying around in the kiln during firing because of the
>down draft air movement effects and landing on other pots.
>
>Is this a possibility?......am I courting disaster?...and should stop using
>the silica sand?
>
>

--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au

Arnold Howard on mon 16 may 05


If you use silica sand, I would caution you about handling the ware after
you remove it from the kiln. Some people hold the pieces over the kiln as
they brush the sand off. This has led to element failure, because the sand
floats down into the kiln and into the element grooves. As you probably
know, the sand can burn out elements.

If you keep the sand no closer than an inch from the edges of shelves, you
shouldn't have a problem with sand falling off the shelves during firing.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net / www.paragonweb.com

From: "Debbie White"
> I am just getting use to using a Bailey Down Draft Vent on my electric
> kiln.
> I use kiln wash on my shelves...but occasionally I sprinkle a little bit
> of
> fine silica sand on a kiln shelf if I have a pot ..e.g.. a lid for my
> butter
> dishes that I do not want to warp. I am becoming suspect that maybe the
> silica sand may be flying around in the kiln during firing because of the
> down draft air movement effects and landing on other pots.
> Is this a possibility?......am I courting disaster?...and should stop
> using
> the silica sand?