Mary Hays on wed 22 jan 97
I need to raku a 22" platter. Due to the high risk of cracking the platter, I
was wondering if instead of lifting the platter with tongs to the reduction
bin, couldn't I just leave the platter where it is and throw some leaves on
it to ignite, then just cover it with a metal/steel tub, and uncover it in 30
minutes??? Do you think I can do this successfully without ruining my raku
kiln (ceramic fiber) and fire bricks??
Thanks in advance for the help!!!
Mary Hays
jhaysbsmo@aol.com
Keith Chervenak on thu 23 jan 97
Mary,
If the base of your kiln is also fiber you will probably get a good
enough air seal to achieve an adequate reduction however, you will
permanantly blacken the fiber and you will most likely need to place a
heavy, fireproof object on top on the washtub to keep that seal tight
throughout the PFR. I also fire large pieces and use a washtub over them
for PFR, but I fire the piece on a heavy gauge stainless steel tray which I
lift from the kiln with gloves and move to the reduction area. I line the
top of my washtub with full sheets of newspaper, they will stay in place.
This saves me time and helps my thin pieces which tend to cool and oxidize
quickyl. Obviously I am well protected with special gloves, glasses, and
clothing and my kiln is a top hat fiber which allows me easy access to the
tray. It is also desirable to have a helping hand or two around.
I guess this doesn't directly answer your question but maybe it
will be of some help. Let us know how it turns out for you. Good luck-
Keith
Keith Chervenak
kac2@po.cwru.edu
Case Western Reserve University
Cleveland, Ohio U.S.A.
Ken Nowicki on thu 23 jan 97
In a message dated 97-01-22 09:18:17 EST, Mary Hays wrote:
----------------------------Original message----------------------------
I need to raku a 22" platter. Due to the high risk of cracking the platter,
I
was wondering if instead of lifting the platter with tongs to the reduction
bin, couldn't I just leave the platter where it is and throw some leaves on
it to ignite, then just cover it with a metal/steel tub, and uncover it in
30
minutes??? Do you think I can do this successfully without ruining my raku
kiln (ceramic fiber) and fire bricks??
Thanks in advance for the help!!!
Mary Hays
jhaysbsmo@aol.com
------------------------------------------------------------------------------
Mary,
First, you pose an excellent question... and I'm anxious to see what kind of
responses you'll receive. I too have wondered about this concept for hard to
move raku items.
There was an article 4-5 years ago in CM about an artist that raku fires 6'
ft. tall pots in the Los Angeles (Malibu?) area, and I believe he had a
system in which the kiln was removed from the ware by counterbalance, and a
reduction container was placed over the ware (also by counterbalance) without
moving the piece from the kiln shelves at all.
This seems to make perfect sense, and I too am curious about this concept. As
far as doing post-fired reduction to 22" platters, I can only speak from my
experiences firsthand. I too have done some large platters, and my approach
is as follows:
When ready to remove from the kiln, I carefully spread my tongs wide enough
to reach under the platter and cradle the piece from underneath, bracing my
wrists and forearms on the handle of the raku tongs for support. I have
previously prepared an area near the kiln in some sand with combustables
already layed out. Carefully laying my platter onto this area, I then add
more combustables and finally cover with an inverted large metal washtub (you
can get these an most any hardware stores). Carefully twisting the rim of the
washtub into the sand, I kick up more sand around the rim to make a tight
seal. This seems to work fine for my purposes for the time being.
My only real concern about leaving the piece on the kiln shelf, and reducing
it from there, is that the extensive heat retained by the shelves and the
kiln furniture may have an adverse effect on the post-firing results of the
piece. This of course depends upon kind of results your are trying to
achieve. My experience with raku fired jewelry, in which I simply placed the
whole shelf full of jewelry into a reduction chamber was that of "over
reduction" due to the heat of the kiln shelf... thus I had to make some
adjustments in cooling the shelf full of jewelery for X amount of seconds
before reducing to achieve the results I was looking for. I am sure you could
make the same adjustments post-firing a platter while on the kiln shelf,
however this may take some extensive experimenting.
I'll be watching to see what other suggestions or experiences arise from this
thread. Interesting... Thanks for bringing it up Mary! :)
Ken Nowicki ...from Sherman Oaks, where it's light showers and 58 degrees
today.
Harvey Sadow on thu 23 jan 97
Mary Hays wrote:
>
> ----------------------------Original message----------------------------
> I need to raku a 22" platter. .....
Hi Mary,
Try firing your platters on edge, propped against a stack of softbrick,
with the rim sitting on a soft brick, not on the kiln shelf. this tends
to make the edges and the center heat up more evenly, and makes it
easier to get the plate out of the kiln without stressing the rim. I
fire my large flared plates like this and do not have any more cracking
than with vessels, a very tiny percentage. For large plates, I actually
have someone help me remove plates from the kiln by pushing against the
center of the plate with a long stick, while I cradle the back of the
plate with my partially open tongs. I kind of scoop the plate up from
behind, and rest it on my tongs instead of grabbing the edge. The
pressure from the stick helps the plate end up on top of the tongs.
Hope this makes sense! It's a bit hard to describe.
And yes, you can certainly reduce inside the kiln, but the extreme heat
of the chamber will affect the effort profoundly, and your degree of
control diminishes considerably. I used to reduce very large pieces
inside of a raku car kiln. It worked.
Good luck, Harvey Sadow
Jon Lovejoy on thu 23 jan 97
In a message dated 1/22/97 2:18:13 PM, you wrote:
<<----------------------------Original message----------------------------
I need to raku a 22" platter. Due to the high risk of cracking the platter, I
was wondering if instead of lifting the platter with tongs to the reduction
bin, couldn't I just leave the platter where it is and throw some leaves on
it to ignite, then just cover it with a metal/steel tub, and uncover it in 30
minutes??? Do you think I can do this successfully without ruining my raku
kiln (ceramic fiber) and fire bricks??
I regularly fire platters of this size, made from white stoneware, and pull
them from the kiln with Kevlar gloves, using an older, thrashed pair as
"potholders". (22" platters with tongs can be a bear! : ) I then place the
platter on a small pile of sawdust and cover it with a galvanized washtub. I
get pretty good reduction with this method & if I want the top reduced, I
just lay it down upside-down.
As for reducing in the kiln, you can do it, but heavy reduction in the kiln
can hasten the breakdown of the ceramic fibre, as will the carbon deposits
from throwing in organic matter.
Hope that helps!
Jon Lovejoy
Trabuco Hills, CA, where it's 50o and raining...
KDrescherg on fri 24 jan 97
I have had a lot of sucess rakuing platters without to much mishap. I
really do not give them special treatment. But, the way that I remove them
from the kiln is that I make sure that the tongs are not torqueing the
platter in any way. This is easy to do if your kiln and reduction chamber
are low to the ground and your platter is fired vertically. I worry more
about getting one side of the platter to hot or to cool to fast. platters
are fun to reduce because there is so much surface to play with. God luck
with your platters.
Tadeusz Westawic on fri 24 jan 97
> <<----------------------------Original message----------------------------
> I need to raku a 22" platter. Due to the high risk of cracking the platter, I
> was wondering if instead of lifting the platter with tongs to the reduction
> bin, couldn't I just leave the platter where it is and throw some leaves on
> it to ignite, then just cover it with a metal/steel tub, and uncover it in 30
> minutes??? Do you think I can do this successfully without ruining my raku
> kiln (ceramic fiber) and fire bricks??
>
A friend of mine uses the forked handle from a lawnmower to get under
his platters.
Tadzu
Gerry Punt on fri 24 jan 97
I also do large raku work, up to 42 inches tall by 25 inches in
diameter, and have done some post fire reduction inside a fiber lined
kiln. the main problem that I have had is maintaining reduction for the 4
or 5 hours that it takes for the kiln to cool down. I have been able to
overcome this problem to some extent by placing a container full of very
wet sand in the kiln. the evaporation helps speed up the cooling
significantly and the sand keeps the water from boiling all over the
place. I still have not been able to attain the kind of reduction the I get
when I pull the pieces from the kiln, but, It is a step in the right
direction.
gerry punt
ret on fri 24 jan 97
I don't really want to put my 2cents worth in here, because it might end
up more than $2 worth. But yes, go ahead and reduce large pieces right
inside the kiln, even fibre kiln. Some of largish things (to about 5')
just can't be lifted out. I prefer doing that to removing the kiln.
There are many things to consider: as soon as you throw leaves (I use)
into the kiln, the heat will increase as they burn and you do not have
much control over heat rise or crackling. Through trial and error,
depending on the
glaze, you figure out how long to wait before you introduce the red.
material. (Some of my pots get "fed" leaves for hours, until I feel the
glaze will not change any more, and also,as protection until the piece is
cold enough
so a sudden wind gust will not break it.
The fibre kilns tend to be a bit
drafty, so I usually build hard firebrick around them, or sheet metal
covers) Crackling is usually not as effective because the temp in the kiln
is too stable and even. You might wave the lid of a trashcan over the open
kiln before red. material goes in, and once you hear the glaze crackling,
go ahead. Dampen some of the leaves slightly to vary the density and
inflammability (?) of the material. At the end of red. time,I usually
fill
the entire kiln up with
glass clippings or hay because that seals it all off airtight.
Then you wait anxiously for morning.....
For large platters, I've taken the propane torch out of the firebox and
fired right onto the platter in the kiln and watched the glaze melt and
change and get
beautiful copper reds from a cu wash. If I don't let platters reduce in
the
kiln, I fire them standing on edge so they have less stress to endure
during removal...etc, etc. All common sense.
ELKE BLODGETT email: eiblodge@freenet.edmonton.ab.ca
12 Grantham Place
St. Albert, AB T8N 0W8
403 (458-3445); 403 (727-2395)
Marcia Selsor on fri 24 jan 97
Dear Jon,
My students welded a two prong pitch fork on a 3" steel tube with a ring
and rod handles for leverage. Large pieces are fired (as Harvey
mentioned) on soft bricks which allow the prongs under the piece to be
lifted out. At NCECA my students attended a lecture by someone (I am
sorry I don't know who this was) who used a large drum or garbage can
with straw inside and taped closed with newspaper. The large piece is
set onto other soft bricks and the can is lowered over the piece burning
the newspaper as it goes. This is fast enough to keep the straw in to
cause the post firing reduction.
I personally fire large plaques 22x25" and place them face down on straw
and cover with a galvinized bucket. This also works.
Good luck,
Marcia in Montana
Jon Lovejoy wrote:
>
> ----------------------------Original message----------------------------
>
> In a message dated 1/22/97 2:18:13 PM, you wrote:
>
> <<----------------------------Original message----------------------------
> I need to raku a 22" platter. Due to the high risk of cracking the platter, I
> was wondering if instead of lifting the platter with tongs to the reduction
> bin, couldn't I just leave the platter where it is and throw some leaves on
> it to ignite, then just cover it with a metal/steel tub, and uncover it in 30
> minutes??? Do you think I can do this successfully without ruining my raku
> kiln (ceramic fiber) and fire bricks??
>
> I regularly fire platters of this size, made from white stoneware, and pull
> them from the kiln with Kevlar gloves, using an older, thrashed pair as
> "potholders". (22" platters with tongs can be a bear! : ) I then place the
> platter on a small pile of sawdust and cover it with a galvanized washtub. I
> get pretty good reduction with this method & if I want the top reduced, I
> just lay it down upside-down.
>
> As for reducing in the kiln, you can do it, but heavy reduction in the kiln
> can hasten the breakdown of the ceramic fibre, as will the carbon deposits
> from throwing in organic matter.
>
> Hope that helps!
> Jon Lovejoy
> Trabuco Hills, CA, where it's 50o and raining...
--
Marcia Selsor
http://www.imt.net/~mjbmls/
mjbmls@imt.net
Fay & Ralph Loewenthal on sat 25 jan 97
Mary Hays wrote:
>
> ----------------------------Original message----------------------------
> I need to raku a 22" platter. .....
Mary there seems to be quite a few people who have the same problem as you.
I have been taking large pieces from my gas kiln with a spade that has a metal
shaft and wooden handle. I certainly would not like to get as close as some
people, who use gloves, do. They really must have very good protective
gear. I find with the platter being on small stilts, I can slip the spade under
it and put it into combustibles with safety and no broken platters. I hope this
helps, good luck Ralph
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