Craig Clark on sat 18 may 02
Leslie, you will probably get a wide range of suggestions so here's
mine. First, go out and get yourself a couple new trash cans that will seal
well if you want to get heavy reduction, this will simplify your life.
Without a proper seal you will find that the pots will re-oxidize as they
cool in the cans. If your not concerned with heavy redux, (bright copper),
then continue on with the old models.
The speed at which you transfer your pots from the kiln to the cans
greatly affects the final results. If you are concerned with what you refer
to as scarring (some of us prefer to look upon it as texture and use various
materials such as straw and hay to further it) then do two things- use as
little paper as possible and let the pot cool a bit before putting it into
the can. The problem with letting the pot cool more to lessen the scarring
is that you will not be able to get the type of ruduction that I think you
are after.
As an "inbetween" sort of thing take a few sheets of paper and form a
small nest in the bottom of the can. Don't crumple the paper up just sort of
lay it in and around. Once pot is placed in the nest lay an open sheet of
paper over the top of the piece and cover the can quickly. This should give
you a higher level of reduction with the leaky cans. Keep in mind that using
to much reduciton material is a highly probable culprite for the "scaring."
One other thing to try, if you don't want to spring for the new cans,
is to dig several holes in the ground into which your pieces will fit. Use
them as you would a can. After you have placed the old lids over the top of
them cover around the edge with sand for a nice seal. A little clay around
the point atwhich the handles of the lid pass through the lid will also help
to create a better recuction environment.
You can also set up an area on which you place several pieces of old
broken kiln shelves on top of bricks and sand. Rather than worrying about a
seal from an old lid on your cans (I'm assuming that the cans themselves do
not have holes in them) place the pieces onto the kiln shelves and invert
the cans over the pieces.Then seal the edges with sand.
I would not suggest the reduction in place that you saw in the old CM. I
don't know who was doing it or why, but there is the inherent problem of the
residual heat in the kiln to contend with....not to mention copious amounts
of smoke (cough, cough, cough.)
Which reminds me, when it comes to raku, and I say this to everyone so
please take it as a professional responsibility and courtesy, safety first.
O yeah, did I mention the importance of safety.
Some folks think it's ok to wear shorts, sandals, tanktops, and a pair
of sunglasses while rakuing. They are ignorant or foolish. Keep your hair
well secured and covered as it will burn away quite quickly. Wear long
cotton pants and shirt (no synthetics unless they are specifically designed
to be fire resistant.) Full covering of the feet. Go the extra few yards and
spring for a pair of elbow length kevlar gloves. Avoid doing any deep
breathing while opening the cans. The residual fumes that escape from the
cans post reduction are nasty. The best way to avoid them entirely is to let
the pieces cool completely in the cans before removing them.
If the sand wedging is working well continue with it but keep in mind
that using whatever variety of clay body you have available will play havoc
with any consistency factor that you are after. I'd suggest picking a body
that serves your purposes and sticking with that body. I currently use
BlackJack, Lagunas WSO, and the old body that I mix up from time to time
which is a 100 lb bag of Hawthorn Bond Missouri fireclay, a 50 lb bag of Old
Mine #4 Ball clay, a 50 lb bag of GoldArt, and grog to taste. Depending on
what I'm planning on using the clay for I will vary the grog content from
around 5 to 20 percent.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
If you haven't already done so pick up a copy of Steven Branfman's book
"Raku; A Practical Approach." There are two editions. Each is well written
and will answer many of the questions that arise as you explore raku.-----
Original Message -----
From: "Leslie Ihde"
To:
Sent: Sunday, May 19, 2002 5:44 AM
Subject: sheepish ?s raku
> I'm a self-taught potter, and my know how can be rather spotty. I've
> been raku-ing many of my vessels, using any clay with a great deal of
> sand wedged in. Here are my thoughts and questions-
>
> When do I remove the pot from the kiln to the shredded paper? I've been
> doing it immediately, now slowing down to after a minute to reduce glaze
> scarring. There must be a trick to this. I always seem to scar my
> pots. Perhaps I should wait longer.
>
> Reduction- The best lusters I get are on the lower part of the pot,
> where the best reduction is. My trash can lids are not air tight. I
> sprinkled some old cooking oil on the upper part as they cooled and got
> nicer crackles and some fire. I dribbled this on, alternating with
> covering the trash can for some several minutes and continued to
> influence the effect. How long could this go on?
>
> I'd seen an old Ceramics Monthly picture of a raku kiln where the potter
> introduced refractory material to the kiln rather than remove the pots.
> I have a simple kiln I dismantle at the end of the summer and store-
> the brick and expanded wire mesh kind with fiber blanket inside, so this
> impractical. But has some one come up with a better solution? I do my
> raku alone.
>
> Propane. I remain scared of the stuff, but usually raise the pressure a
> pound every ten minutes. Now I am thinking I am going too fast, having
> seen the Bath Potter's Supply web site and seen some of my glaze flaws
> described. I usually have the whole heating process done within 30
> minutes.
>
> I love the wild, unpredictable aspect of raku, but I would like a bit
> more control. Is that asking too much of the process?
>
> Thanks for any tips.
>
> Leslie Ihde
> Turning Point Pottery Studio
>
>
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__
> Send postings to clayart@lsv.ceramics.org
>
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>
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melpots@pclink.com.
Leslie Ihde on sun 19 may 02
I'm a self-taught potter, and my know how can be rather spotty. I've
been raku-ing many of my vessels, using any clay with a great deal of
sand wedged in. Here are my thoughts and questions-
When do I remove the pot from the kiln to the shredded paper? I've been
doing it immediately, now slowing down to after a minute to reduce glaze
scarring. There must be a trick to this. I always seem to scar my
pots. Perhaps I should wait longer.
Reduction- The best lusters I get are on the lower part of the pot,
where the best reduction is. My trash can lids are not air tight. I
sprinkled some old cooking oil on the upper part as they cooled and got
nicer crackles and some fire. I dribbled this on, alternating with
covering the trash can for some several minutes and continued to
influence the effect. How long could this go on?
I'd seen an old Ceramics Monthly picture of a raku kiln where the potter
introduced refractory material to the kiln rather than remove the pots.
I have a simple kiln I dismantle at the end of the summer and store-
the brick and expanded wire mesh kind with fiber blanket inside, so this
impractical. But has some one come up with a better solution? I do my
raku alone.
Propane. I remain scared of the stuff, but usually raise the pressure a
pound every ten minutes. Now I am thinking I am going too fast, having
seen the Bath Potter's Supply web site and seen some of my glaze flaws
described. I usually have the whole heating process done within 30
minutes.
I love the wild, unpredictable aspect of raku, but I would like a bit
more control. Is that asking too much of the process?
Thanks for any tips.
Leslie Ihde
Turning Point Pottery Studio
Celia Littlecreek on mon 20 may 02
----- Original Message ----- snip
Subject: sheepish ?s raku
> I'm a self-taught potter, and my know how can be rather spotty. I've
> been raku-ing many of my vessels, using any clay with a great deal of
> sand wedged in. Here are my thoughts and questions-
>
> When do I remove the pot from the kiln to the shredded paper? I've been
> doing it immediately, now slowing down to after a minute to reduce glaze
> scarring. There must be a trick to this. I always seem to scar my
> pots.
If you don't want to have scars, without letting your glaze cool, you could
put your combustible in the bottom of your container, then put a piece of
grate, or a cake cooling rack on top of that, then your pot on the grate or
rack. In that way, your pot does not come in contact with the combustible
and your pot will not get scared.
Orchard Valley Ceramics Arts Guild on mon 20 may 02
Hi Leslie,
To avoid scarring, I put a cylinder of hardware cloth (1/4 inch mesh
screen) into my reduction can. I line the space between the cylinder and
the sides of the can with shredded newspaper. The hot pot is put in
the center of the cylinder. It will ignite the paper from incandescent
heat, but the paper never touches it.
I put strips of wet paper or cloth over the rim of the can before closing
it to get a better seal and better reduction. Can lids seem to get looser
over time even if they're tight when you buy them.
Regarding propane, I've been told that the pressure regulator should
not be used for control the firing. The regulator should be left at a
fixed pressure, and a separate control used to adjust the burner. I don't
know why... perhaps one of our kiln experts can explain? In any
case, I know people who fire raku up to temperature in 30 minutes,
but I go a little slower, especially at first when everything is
warming. Takes me about 45-50 minutes. Still, unless you're
getting breakage, I'd say continue doing what you're doing.
Regards,
Bob Nicholson
Leslie Ihde on mon 20 may 02
Bob,
I am getting excellent advice from Clayart, and collecting all of it in
a file. I can't wait to fire again using many of these tips. Thank-you.
Leslie
On Monday, May 20, 2002, at 11:07 AM, Orchard Valley Ceramics Arts Guild
wrote:
> Hi Leslie,
>
> To avoid scarring, I put a cylinder of hardware cloth (1/4 inch mesh
> screen) into my reduction can. I line the space between the cylinder
> and
> the sides of the can with shredded newspaper. The hot pot is put in
> the center of the cylinder. It will ignite the paper from incandescent
> heat, but the paper never touches it.
>
> I put strips of wet paper or cloth over the rim of the can before
> closing
> it to get a better seal and better reduction. Can lids seem to get
> looser
> over time even if they're tight when you buy them.
>
> Regarding propane, I've been told that the pressure regulator should
> not be used for control the firing. The regulator should be left at a
> fixed pressure, and a separate control used to adjust the burner. I
> don't
> know why... perhaps one of our kiln experts can explain? In any
> case, I know people who fire raku up to temperature in 30 minutes,
> but I go a little slower, especially at first when everything is
> warming. Takes me about 45-50 minutes. Still, unless you're
> getting breakage, I'd say continue doing what you're doing.
>
> Regards,
>
> Bob Nicholson
>
>
____________________________________________________________________________
__
> 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.
>
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