Paper clay and Glazing

A student from my recent paper clay workshop asked me this question about paper clay and glazing. Anything you create in paper clay can be bisque fired. After this stage, all the paper has burnt out and the piece acts like any other piece created with a traditional clay body. It will take low fire glazes, hi fire glazes, raku glazes, and underglazes.

One of the advantage of paper clay is that you are able to apply glaze to your greenware piece and take it directly to a mid-range (Cone 6) or high fire (Cone 10) without having to do a bisque fire first. This is due to the tremendous greenware strength of paper clay at the bone-dry stage. The piece being very "thirsty" at this stage will suck up the glaze without any trouble. This uses less energy (either gas or electricity) and is more economical.

I had a greenware piece fired to Cone 5 (gas fired), bypassing the bisque stage without any problems. The art center where I teach and do all my firing does two firings in their big gas kilns - one at bisque and the other at Cone 10 reduction. If you have your own kiln, you may opt to try the one-firing method.

Ink and Clay 36 at the Kellogg Art Gallery, CalPoly Pomona.

Here's a write up about this show by the San Gabriel Valley tribune.

http://www.sgvtribune.com/ci_14716937

The photographer must have taken a liking to my piece, Terra Nova.

Paperclay and Inclusions - Part 4

This may be the first time some people have seen this material (top picture). Rice hulls, also called rice husks is the outer covering of the rice grain. Once this is removed, you have white rice. It took me a while to track this down. Finally I found it at a local feed store. It comes in a 25 lb. bag, is used as bedding for horses and it not expensive.

For my hand-pinch bowls, I wedge the rice hulls into my paperclay. How much to add? If you want more texture, add more rice hull. Use less for a subtler effect. There should still be enough paperclay to hold everything together. You will know it if what you make does not hold up. In that case, add in more paperclay and wedge till the rice hull is evenly distributed in the paperclay. You can also press the rice hulls onto the outside surface of your form but this will give a different kind of look/texture.

This material gives a VERY delicate texture (the second picture is the couples cups on its stand, the bottom picture is a close up shot of the texture) so I opt to use oxides instead of glazes. A heavy application of red iron oxide give a very grayish gun metal color in Cone 10 reduction firing. I often use this oxide to contrast against a lighter colored glaze which I use for the inside of my hand-pinched forms.

In addition to creating interesting textures in paperclay, you can also use the rice hulls as a organic combustion source for your raku post-firing reduction.

Happy experimenting!

Micaceous Clay

I was able to try out two samples of micaceous clay while I was at the Paperclay Artist Symposium earlier this year (see earlier post).

Cynthia Dahlstrom (Greenville, Alabama) who was one of the guest presenters uses micaceous paperclay for her carved relief sculptures. She gets the mica clay from New Mexico Clay Company and then adds paper pulp to the clay.

Here's a direct link to her picture in front of her work taken at the Paperclay Artist Symposium.

http://gallery.me.com/grahamhay#100028/IMG_0119&bgcolor=black

One of the benefits of the paperclay version of the micaceous clay is that it reduces the warping and cracking on her rather large flat panels. Her work is intricately carved, sometimes as many as 5 layers deep, then painstakingly hand-burnished, pit fired and then smoked to achieve the colors and results she is looking for.

I enjoyed her presentation very much and found her to be a very personable artist with southern charm and humor. She even made mica clay fortune cookies for us to try our hands at hand-burnishing these little things. It was a lot of fun.

From the mica clay samples she gave out, I made these two small simple pinch forms (2.25"H x 3"W at the rim). They have been bisqued fired. Mica clay is a low fire clay so cone 06 is high as you would want to go to keep the burnished look.

Grogzilla, Godzilla, Moxilla, etc

I found out about this high-grogged NON-paperclay called Grogzilla™ when I attended my first paperclay workshop with Graham Hay in Santa Clara at Clay Planet back in 2007. It is manufactured by Clay Planet and is rated to Cone 10.

What attracted me to this "traditional/regular" clay was its rough texture and the little bits of "white godzilla teeth." That was my first impression of the feldspar crystals that popped from its surface. (See close up shot below) It does look like little dinosaur teeth so I thought the name was quite appropriate.

This hand-pinched bowl was fired in Steve Davis' kazegama ash kiln at Aardvark. I applied a thin layer of flashing slip on the top 1/3 of the bowl. The rest of the bowl was left bare. You can see the ash glaze over the flashing slip as a slight grayish brown coating. At high temperatures in the kiln, the feldspar crystals in the clay break through the surface and melt into little white globules.

I enjoy this texture very much and have been using this clay in my "sandwich" technique. (See earlier post). Paperclay allows me to incorporate this "regular" clay into my paperclay sculptures.

What's going on?

I made several of these hand-pinched rice mixed with paperclay bowls sometime ago. The inside was coated with Southern Ice porcelain paperclay since I wanted to use the Celadon glaze.

After Cone 10 reduction, I found all my bowls had cracks in them. On the bottom of some of them, it looked like the Celadon glaze had pooled and formed a thick layer.

I was puzzled as to what happened as I had successfully used this method before. I decided to break some of them open to see what was going on inside. The bottom picture shows the culprit and the cause for the cracks.

I concluded that the Southern Ice porcelain paperclay was applied too thickly and in the high fire it contracted more than my regular paperclay and separated from the "shell."

This time around, instead of layering the Southern Ice porcelain paperclay layer by layer using the brush (this is the way I normally do it; it is a slow process but you have control over the thickness of the porcelain application), I decided to do something similar to slip casting, ie pouring my Southern Ice paperclay slip into my bone dry rice-and-paperclay bowls, wait for a while and then emptying the excess out. This resulted in too thick of an application of the Southern Ice porcelain paperclay. My experience with this porcelain paperclay is that it shrinks more than the regular paperclay and when this inner layer is too thick, it is has enough cohesion to pull/shrink away from the bottom of the bowl.

There are several ways to get around this:

1. Go back to layering the inner porcelain layer by hand with the brush method.

2. Use a thinner porcelain paperclay slip.

3. Wet down the bone dry bowl a bit so that it is not so "thirsty" and won't "suck up" the porcelain slip too quickly.

4. Do not wait too long to pour out the excess, if you are using the slip cast method.

I'm back using the #1 method as I can control how many layers of the porcelain slip I apply. I have not experimented with the other methods.

Paperclay and Inclusions - Part 3

This brings me to one of my favorite drinks - coffee!

This is ground coffee that I get back home in Malaysia. As you can see, it is very coarse. Not all the coffee is ground so coarse. I shook my coffee container to bring up the coarsest bits to show the texture. I use it in my french press to make my morning brew.

The grounds can be saved, dried and then mixed with your paperclay to create interesting textures. One caveat. You want to make sure you dry out the grounds completely before you mix it into the paperclay to minimize "blow out" problems