Gary Ferguson on thu 12 jun 03
If thrown, they are thrown upside down. You create a solid doughnut form by
opening the center all the way to the wheel head. Then split the doughnut,
approximately 1/3 (inside) and 2/3 (outside) until the floor of the valley
is the thickness you want. . Pull and close the inside wall. This creates
the dish portion of the double walled pot. Then you pull and shape the
outside wall. This can be a closed form as well or a flared rim to create a
foot, etc. They are kind of fun to throw, but a challenge to start with.
There was a good article in Pottery Illustrated (somewhere around 1999),
that detailed the throwing method.
I understand they an be hand built, but it was mentioned in the article
above the artist and encountered a lot of cracking problems along the seams
if the forms were hand built, and he chose to throw all his.
Gary Ferguson
Raku Clay Artist
Nampa, ID 83687
Visit my site at http://www.garyrferguson.com
Subscribe to Just Raku Newsletter at http://www.JustRaku.com
----- Original Message -----
From: "Beth Ellen Nagle"
To:
Sent: Thursday, June 12, 2003 9:55 AM
Subject: Re: double walled bowls - Examples
> Thank you very much Mr. Ferguson. I have seen bowls like this but was
just
> not sure. I have no idea how they are made! I would think such forms
could
> be hand built as well?
>
> Well, now I had the pleasure to see your work as well. I really like how
> you combine the raku effects with crackle glazes. Really nice. Thanks.
>
> Beth Ellen Nagle
> Ocononomowoc, WI.
> www.apostate.com/~bethellen
>
>
> ----- Original Message -----
> From: "Gary Ferguson"
> To:
> Sent: Wednesday, June 11, 2003 11:16 PM
> Subject: Re: [CLAYART] double walled bowls - Examples
>
>
> > The following are some examples:
> > http://www.garyrferguson.com/gallery6.htm
> > http://www.iflyfish.com/clayturtle/recent_work/PIC00018A.html
> > http://asanvicente.addr.com/Resources/samples/wmo9c.html
> > http://www.milkywayceramics.com/mf/images/dwbowl.jpg
> >
> > Enjoy!
> >
> > Gary Ferguson
> > Raku Clay Artist
> > Nampa, ID 83687
> > Visit my site at http://www.garyrferguson.com
> > Subscribe to Just Raku Newsletter at http://www.JustRaku.com
> >
> > ----- Original Message -----
> > From: "Beth Ellen Nagle"
> > To:
> > Sent: Wednesday, June 11, 2003 8:50 AM
> > Subject: Re: double walled bowls
> >
> >
> > > Can someone direct me to an image of a double walled bowl? I am
having
> > > problems envisioning this.
> > >
> > > Beth Ellen Nagle
> > > Oconomowoc, WI.
> > >
> > > www.apostate.com/~bethellen
> > >
> > >
> > > > Hi All,
> > > >
> > > > Thanks for your replies!
> > > >
> > > > I used to make these often. I always fired them upside down because
I
> > > > closed off the bottom so it was rounded and then made a separate
base
> > > > for them. I would always raku them upside down too, this way the
> carved
> > > > portion turned a nice deep black.
> > > >
> > > > Since I'm on my own now, with only an electric basement kiln I have
to
> > > > change my process. Thus, I didn't close off the bottom of this one.
> > > > It's my first time even having the option of firing it right side
up!
> > > > And with the finer, and as Gary pointed out, variable thickness
> carving
> > > > I was concerned about my prior system. I will definitely fire it
> right
> > > > side up.
> > > >
> > > > The "looks deep but is shallow" is a riot, nice to start the day
with
> a
> > > > laugh! I'll never look at a double walled bowl the same way again!
> > > >
> > > > Looks like another sunny day in Massachusetts, about time too.
> > > >
> > > > Linda
> > > >
> > > >
> > >
> >
>
____________________________________________________________________________
> > > __
> > > > 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.
> > >
> > >
> >
>
____________________________________________________________________________
> > __
> > > 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.
> >
> >
>
____________________________________________________________________________
> __
> > 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.
>
>
____________________________________________________________________________
__
> 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.
Maurice Weitman on fri 13 jun 03
I've also thrown them right-side up, without opening the center to
the wheel head.
I open a cylinder with an extra-thick, low wall, then split it in two
to make another base between the now two walls the same thickness as
the inner base, then alternate pulling up the inner and outer walls,
and when the walls are about equal height and desired thickness, join
them. The result is, viewed from above, a pot with walls that appear
to be extraordinarily thick, but are actually hollow.
Of course, without some relief, the air-tight chamber will explode
when heated, so one must provide anything from a small relief hole to
exuberant carving on the walls to reveal the inner structure. It's
actually quite fun.
Here is a pic of one with
restrained (ineffective, even) carving that was used as a soda kiln
and glaze test firing, but you'll get the idea.
Regards,
Maurice
At 10:39 PM -0600 on 6/12/03, Gary Ferguson wrote:
>If thrown, they are thrown upside down. You create a solid doughnut form by
>opening the center all the way to the wheel head. Then split the doughnut,
>approximately 1/3 (inside) and 2/3 (outside) until the floor of the valley
>is the thickness you want. . Pull and close the inside wall. This creates
>the dish portion of the double walled pot. Then you pull and shape the
>outside wall. This can be a closed form as well or a flared rim to create a
>foot, etc. They are kind of fun to throw, but a challenge to start with.
>There was a good article in Pottery Illustrated (somewhere around 1999),
>that detailed the throwing method.
>
Rod Wuetherick on fri 13 jun 03
> Of course, without some relief, the air-tight chamber will explode
> when heated, so one must provide anything from a small relief hole to
> exuberant carving on the walls to reveal the inner structure. It's
Explode?
That is simply not true. I'm sure others will elaborate on how this is
not only possible but really rather easy.
Rod
Earl Brunner on sat 14 jun 03
Sure, you are right, and if you can't guarantee the firing, or have no
control over the firing, then your points are well taken. What I did
was say that it WAS possible and defined the conditions. Someone with
common sense should know whether or not they can meet the conditions. I
didn't say just do it, it will all work out.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Susan
Setley
Sent: Saturday, June 14, 2003 4:49 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: double walled bowls - Simple How to
In a message dated 6/14/03 5:17:56 PM, brunv53@YAHOO.COM writes:
<< Relief can come in a variety of ways. The guiding principle here
being
that as air is heated it expands, (like most everything else). As the
air inside of an enclosed space tries to expand, it will exert pressure
on the container wall. That pressure may be relieved by providing an
easy exit. But if the trapped air is taken into account, you can handle
it with your firing schedule.
The clay is porous, the air will get out if the rate of temperature
climb is slow enough, but you have to allow for that in your firing. A
single rigid firing routine or schedule will not work for every
situation. >>
But that's exactly what many people are faced with.
Susan Setley on sat 14 jun 03
In a message dated 6/13/03 10:42:38 PM, rod@REDIRONSTUDIOS.CA writes:
<< > Of course, without some relief, the air-tight chamber will explode
> when heated, so one must provide anything from a small relief hole to
> exuberant carving on the walls to reveal the inner structure. It's
Explode?
That is simply not true. I'm sure others will elaborate on how this is
not only possible but really rather easy.
Rod
>>
An artist where I throw recently threw a very large planter with a double
lip. He forgot to put an air escape hole in the lip and a large chunk of the lip
blew out while bisquing. Fortunately it didn't damage anyone else's pots. He
has a master's degree in fine arts/ceramics and he says that was the cause.
Veena Raghavan on sat 14 jun 03
Hi Maurice and all,
Hope you do not mind my adding a bit to your great description. I also
throw double-walled pots rightside up. (have also used Doug Gray's method=
of upside down). If you want a long tapered neck for a vase or bottle
shape, what I do is keep the inner wall thicker, so there is more clay to=
pull up, belly out the outer wall more than the inner wall, then join the=
outer wall, below the edge of the inner wall, complete pulling up the inn=
er
wall, shape it, and so on. Hope this makes some sense.
Hope everyone is having a good summer. We are being "blessed" with more
rain than I can handle here in the D.C. area. =
Veena
Message text written by Clayart
>I open a cylinder with an extra-thick, low wall, then split it in two
to make another base between the now two walls the same thickness as
the inner base, then alternate pulling up the inner and outer walls,
and when the walls are about equal height and desired thickness, join
them.<
Veena Raghavan
75124.2520@compuserve.com
Cl Litman on sat 14 jun 03
I fire enclosed forms all the time and don't get blowouts. Thoroughly
dry, candle overnight, fire it slow at the front end in both the bisque
and glaze. Simple - no masters necessary :<)
Cheryl Litman - NJ
cheryllitman@juno.com
On Sat, 14 Jun 2003 11:28:14 EDT Susan Setley
writes:
> In a message dated 6/13/03 10:42:38 PM, rod@REDIRONSTUDIOS.CA
> writes:
>
> An artist where I throw recently threw a very large planter with a
> double
> lip. He forgot to put an air escape hole in the lip and a large
> chunk of the lip
> blew out while bisquing. Fortunately it didn't damage anyone else's
> pots. He
> has a master's degree in fine arts/ceramics and he says that was the
> cause.
Earl Brunner on sat 14 jun 03
Relief can come in a variety of ways. The guiding principle here being
that as air is heated it expands, (like most everything else). As the
air inside of an enclosed space tries to expand, it will exert pressure
on the container wall. That pressure may be relieved by providing an
easy exit. But if the trapped air is taken into account, you can handle
it with your firing schedule.
The clay is porous, the air will get out if the rate of temperature
climb is slow enough, but you have to allow for that in your firing. A
single rigid firing routine or schedule will not work for every
situation.
It could explode, but it doesn't have to. I seem to recall a clay
artist in the UK that made a bunch of hollow spherical ceramic objects
that actually would float, and turned them loose along the coast, to
wash up on beaches.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Susan
Setley
Sent: Saturday, June 14, 2003 8:28 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: double walled bowls - Simple How to
In a message dated 6/13/03 10:42:38 PM, rod@REDIRONSTUDIOS.CA writes:
<< > Of course, without some relief, the air-tight chamber will explode
> when heated, so one must provide anything from a small relief hole to
> exuberant carving on the walls to reveal the inner structure. It's
Explode?
That is simply not true. I'm sure others will elaborate on how this is
not only possible but really rather easy.
Rod
>>
An artist where I throw recently threw a very large planter with a
double
lip. He forgot to put an air escape hole in the lip and a large chunk of
the lip
blew out while bisquing. Fortunately it didn't damage anyone else's
pots. He
has a master's degree in fine arts/ceramics and he says that was the
cause.
Snail Scott on sat 14 jun 03
At 06:03 PM 6/13/03 -0700, you wrote:
>> Of course, without some relief, the air-tight chamber will explode
>> when heated...
>Explode?
>
>That is simply not true. I'm sure others will elaborate on how this is
>not only possible but really rather easy.
Large pockets of trapped air can explode, but this seems
mainly due to moisture remaining in there, too. IMHO, most
explosions ascribed to 'trapped air' are really steam
explosions. Very dry clay, fired slowly through the lower
temperature ranges, can tolerate quite large air pockets,
especially if the clay is coarse. I've seen volumes
approaching a quart (liter) fired successfully without
any relief holes. Dry clay simply isn't air-tight.
Cracking can occur from the internal pressure caused by
srinkage while drying, though, since the porosity of the
clay is still blocked by moisture. Very slow drying can
be successful, but a vent hole will allow quicker drying
by preventing pressure buildup.
Though not strictly necessary, I still generally put a
relieving hole into my enclosed forms, just to be on the
safe side. The hole can be quite small, though - a single
needle-tool hole is sufficient to vent even a large,
thick sculpture - dry air will find its way out if it has
to. It's dampness that makes ceramics go 'boom', air vent
or no.
-Snail
Susan Setley on sat 14 jun 03
In a message dated 6/14/03 5:17:56 PM, brunv53@YAHOO.COM writes:
<< Relief can come in a variety of ways. The guiding principle here being
that as air is heated it expands, (like most everything else). As the
air inside of an enclosed space tries to expand, it will exert pressure
on the container wall. That pressure may be relieved by providing an
easy exit. But if the trapped air is taken into account, you can handle
it with your firing schedule.
The clay is porous, the air will get out if the rate of temperature
climb is slow enough, but you have to allow for that in your firing. A
single rigid firing routine or schedule will not work for every
situation. >>
But that's exactly what many people are faced with.
Susan Setley on sat 14 jun 03
In a message dated 6/14/03 5:17:27 PM, cheryllitman@JUNO.COM writes:
<< I fire enclosed forms all the time and don't get blowouts. Thoroughly
dry, candle overnight, fire it slow at the front end in both the bisque
and glaze. Simple - no masters necessary :<)
Cheryl Litman - NJ >>
People who share kiln space with others, and who cannot be guaranteed that
these steps can or will be taken, however, might do other people and their pots
the courtesy of a pinhole.
What happened, happened. This guy is an expert potter, starting to get
international recognition. If it can happen to him, it is no freak occurrence. At
the very least I think those who share kiln space should take steps. Exploding
during glazing would be even worse as the blown out pieces would stick to other
people's work.
Ned Ludd on tue 17 jun 03
> > Of course, without some relief, the air-tight chamber will explode
>> when heated, so one must provide anything from a small relief hole to
>> exuberant carving on the walls to reveal the inner structure. It's
>
>Explode?
>
>That is simply not true. I'm sure others will elaborate on how this is
>not only possible but really rather easy.
>
>Rod
I believe Rod is right. I tested this theory by throwing a hollow
doughnut of porcelain some 8 inches in diameter and 2 inches
ring-thick. No vent holes at all. Glazed and fired it to cone ten.
Came out fine.
... and another pottery myth bites the dust.
Ned
*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~
I am certain of nothing but the holiness of the Heart's affections and the truth of the Imagination.
-John Keats
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