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help with designing a special order piece

updated sun 17 sep 06

 

Nancy Braches on wed 13 sep 06


Hi everyone

I have a little dilemma and am hoping to find some help. I have 2 kilns that are 27 1/2" max height inside. I have a special order for a tall vase that is 30" high and no wider than 12". The design is smaller at the base opening to 12" max width and closing to about 4".

Making it one piece, not a problem but I cannot fit it in my kiln (I figure 35" height is necessary). The piece will never hold water so it does not need to be waterproof. This is going ino a hallway with a lot of traffice so I explained it would be best to make the base heavy since it is thin and tall and will have even taller dried flowers in it. I felt top heavy could be a problem and also being in a high traffic area, it would be safer to be bottom heavy.

So the dilemma is how to make it in 2 pieces, connect it so it looks like one after firing.....can anyone help?

Thanks in advance

Nancy
HIlltop Pottery


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L. P. Skeen on thu 14 sep 06


Nancy, this is also sounding like something for which you need to check =
out the Nov/Dec issue, 2004 of Pottery Making Illustrated. The cover =
story is about Cheryl Tall's work, making large sculpture (i.e. lifesize =
plus) in small kilns using a modular method. www.potterymaking.org. If =
you can't find the mag lemme know and I will copy and send you the =
article.

L. P. Skeen, Summerfield NC
Get your 2007 Clay Lover's Calendar at =
http://www.living-tree.net/calendar.htm

----- Original Message -----=20
From: Nancy Braches=20

I have a little dilemma and am hoping to find some help. I have 2 =
kilns that are 27 1/2" max height inside. I have a special order for a =
tall vase that is 30" high and no wider than 12". The design is smaller =
at the base opening to 12" max width and closing to about 4".

Stephani Stephenson on thu 14 sep 06


Nancy
One option is to section the piece during construction
the sectioning needs to be thought out so that it works
functionally:

you need to think of the piece , almost as a 'lidded' piece
build protrusions, phalanges, etc which project from one section into
the other
to stabilize and help guide and fit the pieces together during drying,
firing and reassembly.
build the joinery so that pieces can balance and support themselves in
the kiln on their own

aim for an even firing top to bottom to get even shrinkage throughout
. If that is difficult try to have the parts of the piece that are
joined in the same area of the kiln

For example :Say the bottom section A is 24" tall and is sitting on
the kiln bottom
Section B is the top piece and is 8" tall and will fit into the kiln
next to Section A/
Rather than setting B on the kiln floor next to A...stilt it so that it
too is in the top part of the kiln...

pieces can be fired on edge or even upside down if need be.

the piece is usually dried as one piece even if it is fired in sections.
the weight of the piece needs to be accommodated while drying and
firing
as mentioned the line and structure of the joinery, must allow for the
piece to be supported in firing
also joinery needs to work visually, and this is where your
resourcefulness comes into play
as you design the sectioning
a section cut does not have to be a straight line but can move in
contour with whatever is going on visually and structurally in the
piece.
there are many methods to doing this.
also some resources. "Large Scale Ceramics" by Jim Robson is one
somewhere I have seen a nice step by step on sectioning but can't
recall where I saw it.


the other approach is to extend the size of the kiln.
if you have a sectioned Skutt for example you can disassemble the
rings, place the sculpture in the kiln, build up the kiln again
and extend the top of the kiln to allow for the height.

if you don't have an extra spacer ring
you can remove the kiln lid from its hinge
build up an extending 'ring with soft brick , and fiber
then place the lid on top of that.

This can be useful, especially if your piece is too tall in the
greenware stage but shrinks down enough to fit in the regular size kiln
for glaze firing

don't know your clay or glazes firing temp or anything about the
piece or how it is constructed or handled , but usually the kiln can
handle an extension like this and still give you a decent firing

As far as joinery after the fact...you'll want to decide on epoxies
and construction adhesives verses mortar and grout. or even extra
physical reinforcement on the inside ..much depends on the piece, wall
thickness
weight, balance, size of gap between sections, etc.

Stephani Stephenson
steph@revivaltileworks.com
http://www.revivaltileworks.com

Stephani Stephenson on thu 14 sep 06


Nancy
P.S.
remember to keep section rims robust and and any phalanges angled so
pieces don't get hung up,
preventing your sections from separating after drying.

Sometimes a separating layer of plastic or paper left in place is
helpful for separation

you can build first , then section and reinforce
or build section at a time
Make a paper template of the top of section A to get you started with
bottom of section B , etc.

Claybody make a big difference in these larger pieces and how to best
approach them.

also , visually speaking ,
the place where pieces meet can also become a visual element
rather than something hidden

good luck with your project!

Stephani Stephenson
steph@revivaltileworks.com
http://www.revivaltileworks.com

Snail Scott on thu 14 sep 06


On Sep 13, 2006, at 10:05 PM, Nancy Braches wrote:
> ... I have 2 kilns that are 27 1/2" max height inside. I have a
> special order for a tall vase that is 30" high...
> So the dilemma is how to make it in 2 pieces, connect it so it looks
> like one after firing...


If the design has a natural 'break' point, like the
base of a lip flare, or a ridge above the foot, or
some such, you can put the joint there. If there
isn't such a feature, you might want to design
one in. This is mainly if you are planning to glaze
the result, though it also help camouflage the
discontinuity in other surfaces as well.

30" isn't really huge, so this is very do-able. I like
to approach this in one of two ways. One is to do
it is two parts, which works well for handbuilding,
but takes a bit of skill and a whole different process
if throwing. For handbuilding (coil, for example),
go up to a good height, then level the top edge.
Make the top a little thicker. Put two layers of dry
cleaners' plastic across, with a hole in the middle
like a doughnut. Continue to build up from there
until complete. Allow to dry normally, then separate
the parts and fire each. If the clay is a bit pyroplastic,
make sure the top section is fired on sand or grog
to allow free movement and reduce shelf friction.

If throwing, throw the bottom, and measure the
width. Throw the top half to the same diameter.
After stiffening a bit, put the top on the bottom half
and true up the fit. A little sand in the joint will keep
it from sticking together. Let it dry a bit more before
separating the parts.

Alternatively, it could be made in one piece by
whatever method you prefer, and cut afterward. A
hacksaw blade attached to a handle (one ended,
not the regular hacksaw frame) works OK on stiff
leather-hard clay. Mark the cut line before beginning;
the flatter and more horizontal the cut, the less
warpage there will be in the upper half during firing.

After firing, use paste epoxy to put the parts together.
It won't drip like regular gel epoxies can. Don't let the
epoxy fill all the way to the surface, and tool it back
with a stick if it squishes out. If these are bare clay,
mix up a grout and color it with oxides to match the
color of the clay.If they are will be glazed, engobed,
or painted, use auto-body filler to bring the surface
out flush with the rest of the form, and sand to the
correct contour. (Body filler takes paint well; epoxy
does not. That's why you don't want the epoxy to fill
all the way to the surface.) Use paint to simulate the
effect of the surrounding surface. There are high-gloss
coatings which can give a look similar to gloss glazes.
It will never look quite the same, but you can come
close, especially if the design makes it seem natural
for there to be something different about that spot on
the form.

Another option: take the lid off your kiln, lay a single
course of softbrick around the edge, and set the lid
on top. The extra height is little enough that it
shouldn't make much of a cold spot.

-Snail Scott

Ann Brink on thu 14 sep 06


Nancy- years ago I had a similiar order and problem. This is what I did and
It worked:
Put the kiln lid in the open position. Packed refractory fiber around
the metal hinge parts.
Stacked insulating bricks on top of the kiln bricks up to the necessary
height, and wrapped with ref. fiber.
After loading the pot (another story) placed kiln shelves on top. I
forget if I angled the bricks in enough so the normal ones would fit, or if
I used other larger ones....
More refractory fiber over the shelves.

I did this for both the bisque and glaze firing (cone 6)
I'm not advising this, but it worked with no damage anywhere.

Ann Brink in Lompoc CA


> Hi everyone
>
> I have a little dilemma and am hoping to find some help. I have 2 kilns
> that are 27 1/2" max height inside. I have a special order for a tall
> vase that is 30" high and no wider than 12". The design is smaller at the
> base opening to 12" max width and closing to about 4".
>
> Making it one piece, not a problem but I cannot fit it in my kiln (I
> figure 35" height is necessary). The piece will never hold water so it
> does not need to be waterproof. This is going ino a hallway with a lot of
> traffice so I explained it would be best to make the base heavy since it
> is thin and tall and will have even taller dried flowers in it. I felt
> top heavy could be a problem and also being in a high traffic area, it
> would be safer to be bottom heavy.
>
> So the dilemma is how to make it in 2 pieces, connect it so it looks like
> one after firing.....can anyone help?
>
> Thanks in advance
>
> Nancy
> HIlltop Pottery
>
>
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> All-new Yahoo! Mail - Fire up a more powerful email and get things done
> faster.
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Nancy Braches on sat 16 sep 06


Thank you all for your great ideas! I'm off to the studio to design.....

Nancy
Hilltop Pottery


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