Earl Brunner on wed 1 jun 05
From: "Vince Pitelka"
To: "Clayart"
> Think about it. Leatherhard pot and wet plastic clay. Will they
shrink at
> the same rate? Who will shrink more and whom less? What happens when
the
> shrinkage differential is large? Who gets broken?
There is not much to add to Rod's good advice, except to say that
whenever
my students have problems with cracks around the handle connections,
especially on the lower edge of the upper connection, it is because
they
waited too long to apply the handles. You want the handles to still be
very
soft after they are applied, so that you can adjust the profile to your
satisfaction once they are on the pot. So the only solution is to
apply the
handles at the earliest possible stage. You can set the mug on a small
banding wheel while installing the handle, and rotate it to check out
the
profile. Also, you can always stick a finger down inside to apply
corresponding pressure where the handle is installed, to avoid
distortion of
the form.
It is always a good idea to install handles as soon as possible, while
the
pot is still very damp, but this will vary some depending on your
claybody.
A sandy or groggy stoneware clay is much more forgiving. But no matter
the
claybody, be sure you are applying significant pressure in attaching
the
handle at the upper and lower points, to make sure you are squeezing
all of
slurry out of the joint. If any soft slurry remains in the joint, you
can
pretty much count on a crack appearing.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Earl Brunner
e-mail: brunv53@yahoo.com
Pfeiffer, Dan R (Dan) on thu 2 jun 05
> Think about it. Leatherhard pot and wet plastic clay. Will they
shrink at
> the same rate? Who will shrink more and whom less? What happens when
the
> shrinkage differential is large? Who gets broken?
To add to the other very good advice I would suggest wrapping the mugs in
plastic after you get the handle on. This stops the mug from drying and
after a day or two both mug and handle have about the same amount of water.
This is working very well for me. I have found it very hard to catch the
mugs where they are dry enough to trim and put a handle on without making a
mess of the shape but with the addition of lots of plastic on our drying
racks to slow things up I am having much better luck in finding a pot that
is "just right" for a handle.
Dan & Laurel in Elkmont Al
Potters Council Members
Peter Cunicelli on thu 2 jun 05
I'd like to add my $02 folks. My work consists of pretty stiff and dry
slabs. When I add a handle to anything, I like to take a tiny piece of
newspaper, wet it and put it on the spot where I'll be attaching the
handle. The size is about the size of the area where I'm attaching the
handle. I leave it on there for at least an hour or so. I monitor it so
that it doesn't get too wet and when it's ready, I attach the handle.
Almost always the handle is more moist than the body. I rarely have
problems with cracks where the handle is attached.
Peter (www.petercunicelli.com)
On Thu, 2 Jun 2005 08:21:36 -0500, Pfeiffer, Dan R (Dan)
wrote:
>> Think about it. Leatherhard pot and wet plastic clay. Will they
>shrink at
>> the same rate? Who will shrink more and whom less? What happens when
>the
>> shrinkage differential is large? Who gets broken?
>
>To add to the other very good advice I would suggest wrapping the mugs in
>plastic after you get the handle on. This stops the mug from drying and
>after a day or two both mug and handle have about the same amount of water.
>This is working very well for me. I have found it very hard to catch the
>mugs where they are dry enough to trim and put a handle on without making a
>mess of the shape but with the addition of lots of plastic on our drying
>racks to slow things up I am having much better luck in finding a pot that
>is "just right" for a handle.
>
>Dan & Laurel in Elkmont Al
>Potters Council Members
>
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Gene & Dolita Dohrman on thu 2 jun 05
Just my 3 cents...I have a slurry mix of Lana's Magic Water, clay I am
currently using and a little bleach to keep it fresh.. I score and dab this
on before adding my handle (and, thanks to all the folks here, am pulling
handles on the mugs and they are coming along nicely). A few may show
hairline cracks around the very edges but not much more, once glazed it is
gone. I had to remove a handle once and instead of popping off just the
handle, the whole side came away, handle intact. Works for me! Also, I
have a pretty good damp box that they sit in till I decide they are dry
enough put on an open shelf.
Dolita
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Marcia Selsor on thu 2 jun 05
> Things are real dry in Montana and I have to watch porcelain
> handles really close to avoid cracking.
I wax them to slow down the drying of the handle compared to the pot.
Marcia Selsor
Potters Council Charter member
>
Rod Wuetherick on thu 2 jun 05
"You can wax handles if they are drying out too quickly."
Why? It makes much more sense to me to a entire row of mugs in plastic in
terms of time instead of waxing. Also I have found that waxing in some
circumstances can make the problem even worse. For example; if you have
waxed teh handles how will you see and perhaps rub down unsightly micro
cracks should they occur?
What some call "magic water" also known by brandname as Darvan I use for
attaching mug handles if I'm not pulling them off the mug as when I use an
extruded handle for some forms. I suppose you could use it (Darvan) when
pulling as well but I like to use Darvan enhanced slip then. I use approx.
20cc of Darvan to a 32 oz container of slip. I actually don't measure the
Darvan I just use about 3 caps full in the 32 oz container.
Anyways you folks that use wax if I'm missing something could you tell me
why using wax is/could be better than just using plastic? I'm interested in
your experiance with this as I really never found it effective or efficent
in terms of time.
BTW plastic. Whereever you are look in the yellow pages for drycleaner
supplies. I bought a roll of drycleaner plastic for $45.00 some years ago. I
think that over 75% of it is still on the roll, good chance it will out last
my potting career. I just rip them down the center and they cover a 4' ware
board of work quite nicely.
Caveat is I use a heavier plastic for mugs and lay it on the ware board in
such a way as the mugs are set on the bottom half of the plastic. Then I
fold the other 1/2 over the mugs and there is anough length to fold under
the board. I just leave them in there untill they are pretty much dry.
Everything else is wrapped in drycleaner plastic.
peace,
rod
Daniel Semler on fri 3 jun 05
Hi Rod,
I use wax on handles.
But then I'm sufficiently insane as to try to make coffee mugs out of Southern
Ice. Here's what I do.
Throw mug, on bat, and cut it free.
Leave until morning in coolish garage/studio.
Flip all coffee mugs over onto a piece of wall board, so they are on their
rims. Put a piece of dry newspaper in with them. Cover with plastic. (Got this
from RR).
Check the daily or so.
When ready (can be up to a week later), trim.
Pull handles off the mug. I don't generally pull handles and then attach them.
I just use a slurry of the clay and water to attach the handle.
Get four or six done depending on shape, and thus how many fit on board.
Clean-em up. Wax the joins top and bottom, outside only.
Flip on their rims, add newpaper, cover with plastic.
Wait about a week, checking periodically.
Basically, I try to do everything very slowly, as porcelain is apt to dry too
quickly. I believe that waxing on the outside helps because the the water must
slowly disperse through the mug wall to escape. I think its helpful to have
several mugs under plastic as they can exchange moisture and create a slightly
humid environment. The newspaper also appears to help regulate the water loss
and prevents condensation back onto the pots.
Works for me. But with porcelain, its a matter of learning to live with a
problem child.
BTW I've never tried rubbing down micro cracks, so I guess I never look for
them, or perhaps that's the other way around.
Thanx
D
>
For example; if you have
> waxed teh handles how will you see and perhaps rub down unsightly micro
> cracks should they occur?
>
> Anyways you folks that use wax if I'm missing something could you tell me
> why using wax is/could be better than just using plastic? I'm interested in
> your experiance with this as I really never found it effective or efficent
> in terms of time.
Peter Cunicelli on fri 3 jun 05
Thanks Lee. The slabs are probably too stiff for the wax to do any good
by the time I'm ready to put the handle on.
I've also started using a modified paper clay slip. I use the Magic Water
as well, when making the slip. I just started using it so I'm not totally
sure what my results will be. Also, this new studio is a LOT drier than
the other. So, clay dries quickly. It's got a great view and awesome
energy, though.
Peter (www.petercunicelli.com)
Lee Love on fri 3 jun 05
Rod Wuetherick wrote:
>"You can wax handles if they are drying out too quickly."
>
>Why?
>
>
I have not done this since leaving my teacher's workshop, but...
Sometimes you want the body surface to dry, like when you dry inlay
before scraping.
Also, if you are dipping a mug and do not want slip on the
handle, you can wax the handle.
You can always put the handle on after slipping, but typically,
your body will be dryer than the handle. Really depends upon the
situation.
>It makes much more sense to me to a entire row of mugs in plastic in
>terms of time instead of waxing. Also I have found that waxing in some
>circumstances can make the problem even worse. For example; if you have
>waxed teh handles how will you see and perhaps rub down unsightly micro
>cracks should they occur?
>
>
I would change my clay or change my method if cracks
occurred on the handles. Typically, they become more pronounced in the
bisque. Cracks at the attachment to the body are a different
matter. We use a small diameter bamboo stick, cut on an angle at one
end. Popsicle sticks work too. You can also rub seams after bisquing
if small ones appear. But cracks on the handle itself are problematic.
>What some call "magic water" also known by brandname as Darvan
>
>
I just use slip from my throwing bowl. It works. ;-)
>BTW plastic. Whereever you are look in the yellow pages for drycleaner
>supplies. I bought a roll of drycleaner plastic for $45.00 some years ago. I
>think that over 75% of it is still on the roll, good chance it will out last
>my potting career. I just rip them down the center and they cover a 4' ware
>board of work quite nicely.
>
>
This plastic is too thin and can smudge wet clay. Our cats
will also walk on it. :-( Yes, our cats wreck pots sometimes (they
were a terror when I rescued 5 that were left under a box in the Jinja
woods next to our house. ) But they kill posionous snakes and
rodents, which make them worth their keep.
--
李 Lee Love 大
愛 鱗
in Mashiko, Japan http://mashiko.org
http://hankos.blogspot.com/ Visual Bookmarks
http://ikiru.blogspot.com/ Zen and Craft
"With Humans it's what's here (he points to his heart) that makes the difference. If you don't have it in the heart, nothing you make will make a difference." ~~Bernard Leach~~ (As told to Dean Schwarz)
Lee Love on fri 3 jun 05
Peter Cunicelli wrote:
>I'd like to add my $02 folks. My work consists of pretty stiff and dry
>slabs. When I add a handle to anything, I like to take a tiny piece of
>newspaper, wet it and put it on the spot where I'll be attaching the
>handle.
>
>
You can wax handles if they are drying out too quickly.
--
李 Lee Love 大
愛 鱗
in Mashiko, Japan http://mashiko.org
http://hankos.blogspot.com/ Visual Bookmarks
http://ikiru.blogspot.com/ Zen and Craft
Karen Sullivan on fri 3 jun 05
I had problems with attachments and handles....
Until...
I was taught to attach as soon as possible...
So within an hour or so after throwing a cup...
Just so it stands up to the weight of the handle that would
Cause pulling on the wall and deforming the cup...
I attach the handle...
I have no problem with handles or
Attachments cracking away...
You want the same water content in the clay
For joining parts...I throw cups...and immediately
Pull handles...let sit...then attach
The trick is that the clay dries from the
Outside surface toward the interior...
The reason we score....is to break up the
Dry skin/shell of the outside surface plane....
So the clay does not want to weld together
Through a dry buffer...and cracks...
As an experiment.....smear some soft clay
On to a bone dry, green tile...then watch what happens...
The soft clay shrinks and pulls away from
The dry tile.... So....
I attach the handle before that dry plane
Has developed...
I have no problem with cracking handles...
Porcelain....southern ice....any clay...
Work immediately for the best results...
Bamboo karen
Rod Wuetherick on fri 3 jun 05
"This plastic is too thin and can smudge wet clay."
Lee,
Goes to show peoples different experiance. That is exactly why I use the
thin drycleaners plastic.
It is thin, soft, and lightweight and I find that this works best for not
marking up my pots...
Go figure ;)
peace,
rod
Lee Love on sat 4 jun 05
Rod Wuetherick wrote:
>Goes to show peoples different experiance. That is exactly why I use the
>thin drycleaners plastic.
>
>It is thin, soft, and lightweight and I find that this works best for not
>marking up my pots...
>Go figure ;)
>
>
Yes, we all work differently.
Actually, a wet room is best and a wet box second. Dirt
floor third. The humidity in a dirt floor helps keep work damp (work
that is kept damp is set directly on the dirt floor, with plastic only
covering the top.)
I think we've talked here before about what potters used to
keep their clay moist before plastic: damp cloth and damp storage.
You can even see today, at Hamada's workshop, in the back of the shop is
a dark room made of Oya stone. Plastic clay was put in this room to
keep it useable.
If I build my own studio, I would like part of it to have a
traditional dirt floor. These help control dust (they are watered
every day) and also help when you are trying to keep work damp.
The plastic bags our clay comes in here are larger, having to
hold 20kg of clay. I cut the bottom seam off and then cut the
resulting loop and these sheets are a perfect size to wrap a ware board
completely, or cover the tops (and tuck the edges) of two ware boards,
side by side. As the Retired Foreman Fukuyan always says, "Motai
Nai!" "Too good to waste!"
--
李 Lee Love 大
愛 鱗
in Mashiko, Japan http://mashiko.org
http://hankos.blogspot.com/ Visual Bookmarks
http://ikiru.blogspot.com/ Zen and Craft
"With Humans it's what's here (he points to his heart) that makes the difference. If you don't have it in the heart, nothing you make will make a difference." ~~Bernard Leach~~ (As told to Dean Schwarz)
Susan S on sat 4 jun 05
In a message dated 6/3/2005 9:50:59 PM Eastern Daylight Time,
rod@REDIRONSTUDIOS.CA writes:
> "This plastic is too thin and can smudge wet clay."
>
> Lee,
>
> Goes to show peoples different experiance. That is exactly why I use the
> thin drycleaners plastic.
>
> It is thin, soft, and lightweight and I find that this works best for not
> marking up my pots...
> Go figure ;)
>
> peace,
> rod
I prefer the dry cleaner plastic too. It's soft and doesn't gouge into the
clay the way some of the heavier plastic sheetings do, it wraps around where I
want it nicely, follows forms, and is easy to masking tape in place. If I
need a thicker covering, I just use multiple layers of it. And when a piece
needs to be dried a bit faster, I keep it wrapped in the dry cleaner plastic but
poke a few well-placed holes in it for more ventilation. But it still helps
distribute the moisture better than completely uncovering something.
And since my DH is a concert pianist and lives mostly in suits and tuxes, I
have an abundance of them! (We use a 'green' cleaner so I don't have to worry
about the chemicals either.)
Susie
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