Friday, March 12, 2010

Kiln Wash

Kiln Wash I

Calcined Alumina (EPK) 50%

Kaolin (China Clay) 25%

Silica 25%

Kiln Wash II

Alumina Hydrate 50 Grams

EPK 25 Grams

Silica 25 Grams

Once, when I was a new potter, I bought some kiln wash at a pottery supply, slathered on my shelves and after firing a glaze kiln load, found that everything - I mean everything - stuck to the shelves. After much puzzling, I finally decided the kiln wash was at fault. Nothing I could prove, but ever since, I have mixed up my own wash.

Kiln wash is pretty simple. The above are two mixes--I use the last one usually. I mix it up, put it in a large Yogurt tub and mark it with a black Sharpie. The consistency should be about the same as really thick cream--Thick enough to cover well, yet thin enough to spread evenly.

When I apply it to a new kiln shelf, I use a soft, goat hair brush, apply it on in one direction; then when the first layer is thoroughly dry, lay down another layer in the opposite direction.

Before firing a glaze load, I dust the shelves lightly with Alumina. During the unloading, I tap the empty shelf over a large bucket to reclaim the powder.

All this may seem elementary, but these are the little things that new potters have to learn along the way. It's good to share.

1 comment:

Linda Starr said...

I appreciate your sharing, I will be getting a new kiln soon and I want to do it all right from the beginning, my previous used kiln came with shelves already coated, and I had some premade wash, but I think I'd feel safer making my own. thanks.