Category: teaching

Extruder, coils, Inlaid slip

 

For Week 3 I demonstrated:

How to use the Extruder – I made coils for a 

Coil pot- face jug

Inlaying slip- surface decoration of last week’s boxes

Thanks to Roya our photographer this week!

The extruder is a good tool to make long, even coils or even hollow tubes.

 

These can be handy for any project where you need even sized or a large quantity of coils, handles or production of tiles among other things as with all things clay, the possibilities are endless.

I only caution you that because the clay is being processed by a machine, if you do not transform it, it will lose that “touched” quality and also its connection to us humans because of surface quality and scale. It is different than throwing even though that uses a machine and also different from pulling a handle or rolling a coil where the chief “tool” is our hands.

Set up the extruder by choosing a template  (there is a box with many shapes and sizes to choose from)

and, if there are 4 holes,

putting a screen over 3 of the openings.

Then bolt the template and screen firmly to the bottom of the extruder. Use to the tool to tighten it or clay will leak out.

Wedge up your clay and make it into a sqare shape by tapping it against the table.

Place it in the barrel of the extruder and position the plunger over it and bear down with a steady pressure.

to make a hollow extrusion, you use two parts- a “float” that sits in the middle of your template or jig opening.then attach as before and proceed 

The clay is under such pressure that it rejoins on the other side of the float. Here is the end view of the extrusion

I made a quantity of plain coil

and we went to make a coil pot.

COIL POT

Start with a base the shape you want your pot to be (in this case round) it helps to work on a turntable (I didn’t- so it is not pictured here)

Start your coil at one end, do not attempt to pre-make rings to stack up. They are harder to fit

It helps the coils adhere to eachother if you score and wet your coils as you go along.

You can smooth just the interior

or just the exterior to bond the coils. of course doing both in and out makes it the strongest.

I’m using a small wooden rib for the smoothing.

 

I added more coils going inward to narrow the opening

The Jomon people were the first potters. They were fishermen living in what is now Japan.

Here are two links with photos of the pots.

http://www.metmuseum.org/toah/hd/jomo/hd_jomo.htm

and  http://en.wikipedia.org/wiki/Jōmon

 

I decided to make a traditional face jug

 

Here is the finished goofy guy- I gave him a kewpie doll hair do but he needs a handle.

 

INLAID SLIP

Our surface decoration demo this week was inlaid slip. I used the boxes I made last week. They were quite hard but NOT bone dry. They were still leather hard.

I incised a pattern in the surface with a stick tool.

Then I painted slip into the lines (in this case iron red as I plan to use Josh Green glaze)

I let it dry until it was not shiny nor sticky. Then I took a metal rib and scraped off the slip on the surface, leaving only  the slip that was down in the engraved lines.

Here is what it looks like finished. I will try to put in a picture of the finished product.

Here it is glazed!

 

 

We also talked about GLAZING

Things to remember when glazing:

Read all the signs

Watch for runny glazes, the samples are coded yellow or red for dangerous runs

Wipe off the bottoms of your pots!

Remember glazes have more potentially toxic ingredients especially when they are dry so do wet clean up with a sponge, wash your hands, no sanding or rubbing dry glazes!

Discussion of “transparent” Glazes, Slab “Wrapping”, Sprigging 

For Week 4

A discussion of glazes and group glazing

2 pitchers made of overlapping slabs

Sprigging a small pinch pot

We went into the glaze area and looked at the glazes that are and are not going to let slipped surface decorations show through. 

Here is a list of the best ones (in order somewhat ) that will let the slip show through.

1. Shaner Clear – BUT bare stoneware looks gray. Porcelain looks white. *

2. Celadon– anemic on porcelain but almost as good as clear certainly it will tinge your colors green. A fairly forgiving glaze.

3. The Shinos if they are thin- best is Shino water you can also use Soda Ash water. Stoneware goes Orange-y. You can apply it with a brush or a sponge and you can sponge it off.

4.The Josh’s– I prefer Josh Green as it’s lighter and offers a bit more contrast but every drip and double thickness will show. Josh is fussy that way.

5. Shaner White – colors will look a little pastel-ly or washed out under  this.* note that BOTH the Shaner glazes like to “eat” (absorb) iron and if you use red iron, it can disappear completely under a Shaner glaze.

Glazes from the front room: Rutuile Blue – I’ve gotten some nice results from this; and Randy’s Green **which is not food safe.

After this point, The glazes below can let slip show but it will be in a limited capacity and they should be applied thinly:

Aviva Blue and Temoku

We also talked about application. It is possible to thin your glaze coat by rinsing your pot in water briefly just before dipping it- then it absorbs less glaze.

 

Slab “Wrapping”

This was inspired by a couple of pieces I have that were made by  Robert Yost and I bought at Lill in the mid 1990’s.

I demonstrated by making  a  couple of vessels that involved overlapping slabs

It’s a nice aesthetic touch to thin the edges with a rolling pin or brayer (thanks Jason!)It’s easier to bond them  and they’re less likely to warp up if they are thinner.

Then I took those slabs and just started trying them out until I got a shape I liked. then I attached them to a base and overlapped the thinned out edges.

Now, how to firmly bond these flaps together and keep that “untouched” quality as well as letting the seam show? I used the brayer against the dowel which was on the inside for support. This gave a great surface quality.

after we had a basic container, I decided to fold over the top and enclose the space more.

 I ended up inserting the dowel inside the pot (where my hand wouldn’t fit) and rolling the brayer over it. It was exactly what we needed to maintain surface continuity.

Then I folded over the back and did it again

This gave us a pot with tremendous attitude and posture. As its personality emerged, I realized it need some feet.

Then after smoothing it some with the brayer, I tapped the foot on an immobilized dowel to emphasize those legs.

Here is how it looks afterwards.

 Now it was time to add a handle. Again, we wanted the handle to be consistent in look and surface quality with the rest of the pot so instead of pulling a handle, I once again used the brayer.

I also wanted to show how to make a hollow handle that would have also suited this method. 

I threw out a slab and really rolled the edges thin. then I simply rolled it up-

and curved it. once it was curved, it was strong enough to withstand the brayer treatment to seal down the edge of the overlap.

Then  I attached it to a much less successful piece and braced up the handle to dry a little back to back with the other one.

I have since modified the pot on the left as I thought it was proportionally ugly.

 

 

Sprigging

Sprigging is a traditional surface decoration and it just takes a little practice to get good at it. With a mold it’s a nice way to get a repeating raised pattern. These look good under breaking glazes like Temoku,  Celadon,Josh Green or Shino (there are other too).

I made a couple of very casual sprigging molds last week and they got bisked.

They are pretty shallow.

You make a small coil of clay and smear it down into the mold. It’s key to leave a small part fat so you have something to grasp to pull it out.

as soon as it’s pressed in there, pull it up again- the mold will dry it out if you leave it in there and it needs to be flexible to come out in one piece and also to curve to fit the surface of your pot.

once it’s out you can clean it up a little but the back surface should be thin enough to just blend on to the surface of the pot.

with such fine pieces, you needn’t score- just wet the surface. 

I’ll try to insert a photo of this piece when it’s finished.

 

I also wanted to show Leah’s Jug-in-progress- maybe we can watch it as it develops.

She’s made the base out of coils and is going to let it firm up a bit before adding on top of that. It’s quite difficult to make a large coil pot all at one go. The coils at the bottom need to firm up in order to support the weight of the coils above.

and Roya’s really cool vase! Isn’t that a neat idea? and the flowers can be supported in the various openings.

See how she “faked” it to look like there is a ribbon of clay threading out through the vase wall? I see possibilities for a series here as she explores this idea.