David Martin Hershey on tue 29 nov 11
Hi May,
I like your spec catcher!
I have the same replacement thermocouple on my kiln, and it eventually
seemed to stop shedding (mostly). My specs tend to fall straight down-
maybe less turbulence in my kiln?
I always "cap" my loads with a shelf, because there is a definite cold spot
underneath each of the small holes in the lid for the venting system. Did
you check your kiln with cones on each different level, under the holes?
I've always used 3 posts. With 4 or more, the shelves are never quite
stable. Also, I am somehow under the (maybe mistaken) impression that more
than 3 posts can lead to cracked shelves???
Best, DMH
Beautiful Hermosa Beach CA USA
Where the warm winds are blowing out of the desert tonight...
On Tue, Nov 29, 2011 at 7:24 PM, May Luk wrote:
> Hello all;
>
> Made a speck catcher for my flaky thermocouple. This thermocouple is 2
> months old. If it's not one thing, it's another, *sigh*
>
May Luk on tue 29 nov 11
Hello all;
Made a speck catcher for my flaky thermocouple. This thermocouple is 2
months old. If it's not one thing, it's another, *sigh*
http://www.flickr.com/photos/yamerica/6428601027/in/photostream
I found that plates or bowls on my top shelf tend to have pin holes
like about 10-20 cts spread out, not too bad, but not perfect for a
"simple" transparent gloss. If I refire them, they pin holes go away.
I wonder if I put a kiln shelf over it, it would improve the top shelf
performance. But my kiln is only 4.6 cu ft. ( Skutt KM-1018 - a low 2
rings kiln size) so not often I can fit a shelf in. This is a 2.5"
thick kiln and it doesn't have those itchy kiln wool thingie around
the opening to seal the lid.
Kiln posts - more is better or just 3 each shelf? I am a 3 kiln post
type with the posts always on the same point, but I recently saw my
studiomate's earhenware kiln load, and the posts are all over the
place and more than 4 per shelf, should I say something or it really
doesn't matter because it's low fire? I also want to add that the kiln
furniture is mine and we get charged a flat fee per firing so it
doesn't matter if we fire 10 or 15 hours each time.
Thank you for your time
May
Brooklyn NY
--
http://www.artspan.org/artist/mayluk
http://www.takemehomeware.com/
Lee on wed 30 nov 11
I fire my thermocouples inside a ceramic tube. That might contain your
flakes.
--
Lee Love in Minneapolis
http://mingeisota.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he land
of eternal youth is behind the house, a beautiful land fluent within
itself." -- John O'Donohue
Snail Scott on wed 30 nov 11
On Nov 29, 2011, at 9:24 PM, May Luk wrote:
> I found that plates or bowls on my top shelf tend to have pin holes
> like about 10-20 cts spread out, not too bad, but not perfect for a
> "simple" transparent gloss. If I refire them, they pin holes go away.
> I wonder if I put a kiln shelf over it, it would improve the top shelf
> performance. But my kiln is only 4.6 cu ft. ( Skutt KM-1018 - a low 2
> rings kiln size) so not often I can fit a shelf in...
I think a shelf on top would make it worse, as
t would act as a heat sink and keep the top even
cooler. I cut a 1" thick sheet of kaowool board
(refractory fiberboard) to the size of my kiln, and
just put it on top of the lid when I fire. Lightweight
and easy, and since the kiln lid is not sheathed like
the walls are, there are no expansion issues. In
fact, I suspect it is actually easier on the lid, as it
likely reduces the heat gradient through the lid
brick. I got the board for free, so I'n not sure what
it would normally cost, but I'd pay a fair amount
for the improvement it creates.
> Kiln posts - more is better or just 3 each shelf? I am a 3 kiln post
> type with the posts always on the same point, but I recently saw my
> studiomate's earhenware kiln load, and the posts are all over the
> place and more than 4 per shelf, should I say something or it really
> doesn't matter because it's low fire?
There is no kiln shelf on earth that's so perfectly flat,
and also sitting above an equally flat shelf or floor,
that four posts will even touch the shelf. Three points
are all that will actually touch anyway. For a square
shelf, we might use posts on all corners to clear the
space at the middle for loading, and for high-fire loads
with large shelves, extra posts under a heavy load will
at least restrain the warpage. You can use kiln putty to
bring them all to the same level so that they all actually
touch the shelf. In an electric kiln, more than three posts
seems redundant, and even more so with low fire loads,
as the chances of shelf warpage are close to zero even
over the long term life of the shelf. Extra posts just occupy
useful space, wastefully soak up heat, and make more
work for you.
However...
You do always want to have kiln posts directly under any
posts on the level above. Basic structural engineering:
if the load is supported on a post that is only resting on
an unsupported open span of shelf below it, the load that
the post is carrying (1/3 of the weight of its shelf, plus 1/3
of everything above it) is all resting on one little spot on
the shelf below. If there is a post directly below it instead,
that shelf itself will carry nothing but its own load. This is
one good reason for extra posts: if you have partial shelves
at upper levels that must be supported in a mid-span spot.
For instance, if you have both full-size and half-size shelves
in your electric, you _could_ support the full shelves on just
three posts, but you wouldn't want to put two half-shelves
over that because you would need four posts on that upper
level (three per shelf, but with two shared at the corners).
Better to use four posts for the full shelf if that's going to be
the case, so that all the posts line up. For earthenware,
though, I wouldn't even worry about that. There is so little
pyroplasticity to the shelves at those temperatures that dang
near any support will do. Keep it minimal to save energy and
space.
I use four posts to hold up my bottom shelf, so that I don't
have to ever change them out when I use half-shelves
above. I don't fire very hot (seldom above ^7) but my work
is often quite heavy.
-Snail
Rimas VisGirda on wed 30 nov 11
I have always used a 3 post system with the thickness of shelf gauged to fi=
=3D
ring temp; I prefer 1/2 shelves and sharing posts for a more stable configu=
=3D
ration. I also alternate the split from layer to layer; no reason other tha=
=3D
n I like to... If I need the 2 shelf layer to be perfectly even/flat, I wil=
=3D
l shim the odd post on one side using a straight edge perpendicular to the =
=3D
seam to determine "flatness." By using exclusively 2 half shelves I can alt=
=3D
ernate levels as in accommodating some short pieces on one side and talls o=
=3D
n the other (in which case the shelves can't share posts but i can bring th=
=3D
em together by shimming the top (empty) layer). I have vented kilns and alw=
=3D
ays put an empty shelf as the top layer, I have had cold spots on work if t=
=3D
hey are near a air inlet in the lid. In my 1027 and 1227 I use 5'8" for con=
=3D
e 1 and cooler and 1" for cone 2 and hotter; I fired some 5/8" shelves to a=
=3D
higher cone (don't remember the number) years ago and the shelves
sagged. I managed to straighten them back out by firing them upside down w=
=3D
ith a bunch of posts underneath and bricks for weight on top...=3DA0 My sma=
ll=3D
er diameter kiln only has 5/8" shelves available and they seem to stay stra=
=3D
ight at cone 10... The 3 post system avoids any wobble (3 points determine =
=3D
a plane), whereas 4 posts may not make contact with the shelf (above) if th=
=3D
e posts are not exactly the same height and/or the shelf is not perfectly f=
=3D
lat.=3D0A=3D0AI have taught workshops at venues that have both full and hal=
f sh=3D
elves with neither type sufficient to fill the kiln. It's always a dilemma =
=3D
to go from a 3 post full to a 4 post (2 sharing halves) as I religiously po=
=3D
st over post in stacking. My solution is to use the halves on the bottom (4=
=3D
posts) and either 4 post the full on top or depending on the thickness of =
=3D
the shelves and the firing temp (and if they have any cracks) -or 3 post th=
=3D
e top shelf over unsupported/unposted places of the underneath shelf. I usu=
=3D
ally opt for the 4 post, but it always wobbles and then if I have more than=
=3D
one full at the top I wind up shimming the shelves to make them not wobble=
=3D
...=3D0A=3D0AMaybe way too much information... hope it's not too confusing.=
Nic=3D
e thermocouple splatter gadget. -Rimas=3D0A=3D0A=3D0AKiln posts - more is b=
etter =3D
or just 3 each shelf? I am a 3 kiln post=3D0Atype with the posts always on =
th=3D
e same point, but I recently saw my=3D0Astudiomate's earhenware kiln load, =
an=3D
d the posts are all over the=3D0Aplace and more than 4 per shelf, should I =
sa=3D
y something or it really=3D0Adoesn't matter because it's low fire? I also w=
an=3D
t to add that the kiln=3D0Afurniture is mine and we get charged a flat fee =
pe=3D
r firing so it=3D0Adoesn't matter if we fire 10 or 15 hours each time.=3D0A
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