search  current discussion  categories  kilns & firing - misc 

more on electric kiln : rusted steel base

updated sun 7 nov 99

 

The Brinks on fri 5 nov 99

At 11:55 AM 11/5/99 EST, you wrote:
>----------------------------Original message----------------------------
>At 12:35 PM 11/4/99 EST, you wrote:
>>----------------------------Original message----------------------------
>>Dear All:
>>
>>We have been discussing the rust on a kiln, with began
>>with a thought-provoking comment from Ray Aldridge.
>>
>>During firing, moisture from the greenware turns to
>>steam. As the air expands, it escapes the kiln by
>>pushing its way into the pores of the firebricks.
>>Though the firebricks are very hot, the moist air is
>>driven into the firebricks. When the moisture reaches
>>the cooler kiln case, it condenses, causing dripping
>>around the kiln.
>
>I'm still having a little trouble imagining this. How much steam pressure
>is required to force any substantial amount of moisture through 2.5" of
>firebrick?
>
>Wouldn't the kiln be whistling like a teakettle?
>
>Ray
>
>
>Aldridge Porcelain and Stoneware
>http://www.goodpots.com
>
>
Hi everyone...I looked under my Skutt 1027 this morning , since I too had
noticed a scattering of rust on the floor lately, and see that it has no
sheet metal floor, just a metal stand supporting the whole kiln. The stand
is pretty badly rusted, and it's worse right next to the kiln floor bricks.
I don't think moisture is coming through the bricks; I think there is a
stage in either the warming up or cooling down process that attracts
ambient moisture to the metal stand. Whatever it is, I guess I had better
get some cement blocks soon and slide them under my kiln. The floor bricks
look brand new--no cracks, so there must not be too much movement of
expansion or contraction. The kiln is about 10 yrs. old.

Ann Brink in CA
e-mail billann@impulse.net

Vera Rankovic on sat 6 nov 99

I think you're all on the wrong track.
The moistrure that collects on the inside of the metal sheet, and causes the
rusting is not from the inside,
but from the outstide.
It is caused by condensation from the athosphere since the kiln is warm for
a long time and the metal sheet is heated on
one side, and cooled on the other.
It's just like damp and mold that one can see on the poorly isolated brick
and mortar walls, or basements.

That's why the commercial kilns are covered with crhrome metal.

Vera Rankovic
vrankovic@sezampro.yu
http://www.geocities.com/verasart/
----- Original Message -----
From: The Brinks
To:
Sent: Friday, November 05, 1999 22:58
Subject: Re: more on electric kiln : rusted steel base


> ----------------------------Original message----------------------------
> At 11:55 AM 11/5/99 EST, you wrote:
> >----------------------------Original message----------------------------
> >At 12:35 PM 11/4/99 EST, you wrote:
> >>----------------------------Original message----------------------------
> >>Dear All:
> >>
> >>We have been discussing the rust on a kiln, with began
> >>with a thought-provoking comment from Ray Aldridge.
> >>
> >>During firing, moisture from the greenware turns to
> >>steam. As the air expands, it escapes the kiln by
> >>pushing its way into the pores of the firebricks.
> >>Though the firebricks are very hot, the moist air is
> >>driven into the firebricks. When the moisture reaches
> >>the cooler kiln case, it condenses, causing dripping
> >>around the kiln.
> >
> >I'm still having a little trouble imagining this. How much steam
pressure
> >is required to force any substantial amount of moisture through 2.5" of
> >firebrick?
> >
> >Wouldn't the kiln be whistling like a teakettle?
> >
> >Ray
> >
> >
> >Aldridge Porcelain and Stoneware
> >http://www.goodpots.com
> >
> >
> Hi everyone...I looked under my Skutt 1027 this morning , since I too had
> noticed a scattering of rust on the floor lately, and see that it has no
> sheet metal floor, just a metal stand supporting the whole kiln. The stand
> is pretty badly rusted, and it's worse right next to the kiln floor
bricks.
> I don't think moisture is coming through the bricks; I think there is a
> stage in either the warming up or cooling down process that attracts
> ambient moisture to the metal stand. Whatever it is, I guess I had better
> get some cement blocks soon and slide them under my kiln. The floor bricks
> look brand new--no cracks, so there must not be too much movement of
> expansion or contraction. The kiln is about 10 yrs. old.
>
> Ann Brink in CA
> e-mail billann@impulse.net