Snail Scott on sat 24 apr 04
At 08:41 AM 4/24/04 -0700, you wrote:
>...I noticed quite a gap between the lid and the top row of
>bricks...
I've got a gap, too, especially in front where
years of inappropriate lid-props have worn it
away. Mainly, I figure it saves me from needing
an open peephole. My firings are pretty even,
and I'm not convinced I'm wasting all that much
energy, compared with the overall firing. If I
cared, I'd slide a little kaowool in the gap.
But so far, I don't care quite that much. ;)
-Snail Scott
Reno, Nevada, USA
Maurice Weitman on sat 24 apr 04
Speaking of burnishing with light bulbs...
I was in my studio (which still looks more like a garage with a kiln
and a pugmill) checking out the bisque firing that was nearing an end.
I neglected to turn on the lights and after a few minutes, the
overhead garage door light went out and there I was, me and my kiln,
bisquing in the dark.
I hope this doesn't make me eligible for a visit from Kiln Protection
Services; I didn't mean to do it, it just happened. Never did it
before... honest!
Anyhow, I noticed quite a gap between the lid and the top row of
bricks. Well, maybe not quite a gap, but one that seemed bigger than
I would have expected. Big enough to cast an orange/red stripe on
the wall.
When it cooled I checked the gap and it did seem to be larger than I
would have thought necessary. In fact, I would have thought it
should be pretty tight.
What do you think?
Thanks.
Regards,
Maurice (haven't moved since last night)
Fredrick Paget on sat 24 apr 04
>
>Anyhow, I noticed quite a gap between the lid and the top row of
>bricks. Well, maybe not quite a gap, but one that seemed bigger than
>I would have expected. Big enough to cast an orange/red stripe on
>the wall.
>When it cooled I checked the gap and it did seem to be larger than I
>would have thought necessary. In fact, I would have thought it
>should be pretty tight.
>Maurice
>
I have noticed the same thing with my Bailey/Cone Art kiln. It seems
to open up at high temperature. Something about the way the hinge
pulls down on the back of the cover as the kiln heats up.
Since I have a Bailey kiln vent that sucks air from the bottom of the
kiln I just leave the top peep hole closed and rely on the gap to
give an opening for the vent. Doesn't cause a problem but if there is
anything flammable which that orange glow falls on I would take
measures.
Fred
--
From Fred Paget, Marin County, California, USA
fredrick@well.com
Dave Finkelnburg on sat 24 apr 04
Maurice,
You can get some misalignment between the lid and top row of brick due
to how the hinge is adjusted. If that has happened, the gap will be
narrower (or wider) near the hinge than opposite it. Go back in the dark to
diagnose this possibility.
IF the gap is even clear across, then it's probably nothing to worry
about, just not as tight as a mortared joint, but you can't get that with a
lid.
You can use fiber in the gap, but I don't like having fiber in the
studio being disturbed with every firing, so I don't recommend that.
Good firing,
Dave Finkelnburg
----- Original Message -----
From: "Maurice Weitman"
Sent: Saturday, April 24, 2004 9:41 AM
I noticed quite a gap between the lid and the top row of
> bricks.
Tig Dupre on sun 25 apr 04
Maurice,
Having been alarmed myself, let me allay your concerns. It is natural for a wider gap between lid and body of the kiln to appear when the kiln is very hot. Expansion! Heat expands things. Lotsa heat expands things a lot.
The first time I saw that on my electric top-loader, I thought something was very wrong. I went and bought kaowool, cut it into strips and put it around the rim of the kiln, like a heat gasket. Bad ju-ju! Don't do that!
It's natural. Relax, have another mug of herbal, and sing along with the oldies. It's heat doing that expansion thing!
Best to all,
Tig
in GLORIOUS Port Orchard, Washington, USA
What a day!
Jsmola on sun 25 apr 04
Maurice,
I had the same "scare" one night, or was it early in the morning...I
won't tell if you won't tell :-)
Mine after further "checking" I found out was from the reinforcement
bracket for the handle in the front of the kiln. It was only a small gap
approximately 1/3 to 1/2 of the way around the kiln. The back half
was fine...
Good luck...don't panic! It won't hurt the firing or cooling process!
Good Luck! And...no more peaking in the dark!
The Pottery Pimp
Jaymes
On 24 Apr 2004 at 8:41, Maurice Weitman wrote:
Date sent: Sat, 24 Apr 2004 08:41:24 -0700
Send reply to: Clayart
From: Maurice Weitman
Subject: Bisquing in the dark
To: CLAYART@LSV.CERAMICS.ORG
> Speaking of burnishing with light bulbs...
>
> I was in my studio (which still looks more like a garage with a kiln
> and a pugmill) checking out the bisque firing that was nearing an
end.
>
> I neglected to turn on the lights and after a few minutes, the
> overhead garage door light went out and there I was, me and my
kiln,
> bisquing in the dark.
>
> I hope this doesn't make me eligible for a visit from Kiln Protection
> Services; I didn't mean to do it, it just happened. Never did it
> before... honest!
>
> Anyhow, I noticed quite a gap between the lid and the top row of
> bricks. Well, maybe not quite a gap, but one that seemed bigger
than
> I would have expected. Big enough to cast an orange/red stripe on
> the wall.
>
> When it cooled I checked the gap and it did seem to be larger than
I
> would have thought necessary. In fact, I would have thought it
> should be pretty tight.
>
> What do you think?
>
> Thanks.
>
> Regards,
> Maurice (haven't moved since last night)
>
>
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>
Bruce Girrell on sun 25 apr 04
> >...I noticed quite a gap between the lid and the top row of
> >bricks...
I think that you would find a gap to be the norm. The roof of my
MFT-inspired Stak-O-Brix kiln weighs 650 lbs. The supporting walls are 9
inches thick. Definitely no misaligned hinges. Plenty of surface area. Yet I
can see a gap between the roof and the walls when the kiln is hot.
The brick of the roof is hot on the inside and cold on the outside causing
the brick on the inside to expand relative to the outside. Therefore, the
roof takes on a cupped shape. The underside edge of the roof/lid is lifted
away from the supporting wall resulting in an almost point contact at the
inner edge of the wall which, of course, is glowing. The walls are also
taller on the inside than the outside, due to heating, which adds to the gap
between the roof and the outside edge of the wall.
Ain't nothin' you can do about it. Thermal expansion is an incredibly
powerful force. The scale will be smaller for an electric but the same
forces are at work. Put your hand on the wall where your see the glow. If
you can comfortably keep your hand there then you should be pretty safe.
Bruce "hope that made sense" Girrell
pdp1@EARTHLINK.NET on sun 25 apr 04
Hi Bruce, all...
I was thinking that as well...in my wondering.
I imagine, one could taper the top plane of the sides to a
slight angle ( tipping 'in'), as exceeds slightly the amount
it would gain in expansion, and end up...with about no gap
at all...
Phil
el ve
----- Original Message -----
From: "Bruce Girrell"
> > >...I noticed quite a gap between the lid and the top
row of
> > >bricks...
>
> I think that you would find a gap to be the norm. The roof
of my
> MFT-inspired Stak-O-Brix kiln weighs 650 lbs. The
supporting walls are 9
> inches thick. Definitely no misaligned hinges. Plenty of
surface area. Yet I
> can see a gap between the roof and the walls when the kiln
is hot.
>
> The brick of the roof is hot on the inside and cold on the
outside causing
> the brick on the inside to expand relative to the outside.
Therefore, the
> roof takes on a cupped shape. The underside edge of the
roof/lid is lifted
> away from the supporting wall resulting in an almost point
contact at the
> inner edge of the wall which, of course, is glowing. The
walls are also
> taller on the inside than the outside, due to heating,
which adds to the gap
> between the roof and the outside edge of the wall.
>
> Ain't nothin' you can do about it. Thermal expansion is an
incredibly
> powerful force. The scale will be smaller for an electric
but the same
> forces are at work. Put your hand on the wall where your
see the glow. If
> you can comfortably keep your hand there then you should
be pretty safe.
>
> Bruce "hope that made sense" Girrell
Bruce Girrell on sun 25 apr 04
> I imagine, one could taper the top plane of the sides to a
> slight angle ( tipping 'in'), as exceeds slightly the amount
> it would gain in expansion, and end up...with about no gap
> at all...
I don't see why not. Just a little elbow grease to rub down the top surface
of the IFB at a small angle. At cone 10 the outer edge of the roof sits
about 1/8 to 1/4" above the top of the wall (I'll have to pay more attention
next time), so you wouldn't have to taper it very much.
Seeing the glow emanating from between the bricks helps remind me of the
beast that I have caged inside those walls.
Bruce "it's hot in here" Girrell
Arnold Howard on mon 26 apr 04
The lid should have play in the hinge. If there is no play, the front of the
lid can rise as the bricks heat up. The kiln grows taller as the bricks
expand.
You can check for play in the hinge by lifting up on the back of the lid
while the kiln is cold. The back of the lid should move up and down by about
1/16" or more.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net
From: "Fredrick Paget"
> >Anyhow, I noticed quite a gap between the lid and the top row of
> >bricks. Well, maybe not quite a gap, but one that seemed bigger than
> >Maurice
> I have noticed the same thing with my Bailey/Cone Art kiln. It seems
> to open up at high temperature. Something about the way the hinge
> pulls down on the back of the cover as the kiln heats up.
Ron Roy on mon 26 apr 04
Hi Maurice,
Some kilns have enlarged holes - where the lid hinges to the kiln - which
means the lid is free floating on top of the kiln - self adjusting for heat
expansion.
Anyone see any disadvantages to that?
Just a mater of undoing the hinge and drilling out the holes to give some play.
RR
>Anyhow, I noticed quite a gap between the lid and the top row of
>bricks. Well, maybe not quite a gap, but one that seemed bigger than
>I would have expected. Big enough to cast an orange/red stripe on
>the wall.
>
>When it cooled I checked the gap and it did seem to be larger than I
>would have thought necessary. In fact, I would have thought it
>should be pretty tight.
>
>What do you think?
>Maurice (haven't moved since last night)
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Maurice Weitman on mon 26 apr 04
At 17:56 -0500 on 4/26/04, Ron Roy wrote:
>Some kilns have enlarged holes - where the lid hinges to the kiln - which
>means the lid is free floating on top of the kiln - self adjusting for heat
>expansion.
>
>Anyone see any disadvantages to that?
>
>Just a mater of undoing the hinge and drilling out the holes to give
>some play.
Thanks, Ron, and all who responded, for your help.
I just sent a similar note to Arnold who made a similar observation:
If you don't remember or never knew, the hinge pin on the
Evenheat/Bailey kiln is designed to be free to move vertically about
1/4" in the elongated holes on the bracket.
Unfortunately, it appears that the holes are too tight, and the pin
is binding. I clearly remember this being quite free when I first
got the kiln. I've fired this kiln three times and it's possible
that the heat has changed something.
It would seem to me that if the pin were holding the lid elevated,
the lid would have had to somehow pull away from the kiln. I would
have thought that if the kiln wall were to expand, it would push
against the lid, thereby making it a tighter fit. It seems more like
it did that but at some point cooled down to shrink the walls but the
lid stayed up due to the bound pin.
The gap was most noticeable to/from the rear, but that might be
because the rear is closest to the wall, and the light shining on the
wall was what I first noticed.
I'm about to ream out the size of the slot to allow the pin to float
more freely and will check out my next firing tomorrow.
Thanks again.
Regards,
Maurice
Arnold Howard on tue 27 apr 04
Enlarging the holes for the lid hinge shaft is a very good idea if the lid
is binding at the hinge and lifting in the front. If this is happening, it
may mean that the lid was installed improperly. Before the hinge was
fastened to the kiln case with screws, the bottom hinge section was not
pushed up to allow for lid play. Enlarging the holes fixes the problem.
On some designs, the lid may be lifting at the front due to binding at the
hinge. This can happen even if the lid holes have plenty of play in them.
I'm thinking in particular of kilns with a spring counter-balance at the
hinge.
If your lid is binding, you may be able to fix the problem by loosening a
nut on the end of the hinge shaft. If the hinge is part of a spring
counter-balance system, there may be binding in a bracket assembly.
Inserting a screw driver and twisting can ease binding. This is easier to
understand if you are looking at the hinge on your kiln.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net
----- Original Message -----
From: "Ron Roy"
To:
Sent: Monday, April 26, 2004 5:56 PM
Subject: Re: [CLAYART] Bisquing in the dark
> Hi Maurice,
> Some kilns have enlarged holes - where the lid hinges to the kiln - which
> means the lid is free floating on top of the kiln - self adjusting for
heat
> expansion.
> Just a mater of undoing the hinge and drilling out the holes to give some
play.
> RR
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