John Post

Post's Calcium Matte - ∆ 6

This is the base glaze used with all of the calcium matte tiles on the test tile page. It is the glaze I use on most sculptural work the students do in my classroom. The tile on the left has 0.75 cobalt carbonate and 0.75 copper carbonate added to the base glaze.

Pete's Tomato Red #13 - ∆ 6
A metallic spangly variation. This is the variation I use the most in my studio.

Jen's Juicy Fruit Base variation - ∆ 6
This is the base I use when I test out different colorants with Jen's Juicy Fruit.

Post's Jun Glaze. ∆ 6

A fat white. Looks best over irony clay bodies. It is shown here over a body with manganese specks in it.

Pete's Tomato Red #3 - ∆ 6
Pete Pinnell published a cone 6 iron red glaze in Clay Times. I did some work creating variations of it and sent him images of my results and information about my firing schedule. He wrote an article about my research in the May/June 2009 issue of Clay Times. Pete then followed this first article up with a second one detailing his own research into iron red glazes at cone 6. His research is in the Septermber/October 2009 issue of Clay Times. So if you are interested in iron reds at cone 6, check out each of these Clay Times issues.

Pete's Tomato Red #13 - ∆ 6

a very red variation

Pete's Tomato Red #13 - ∆ 6
a pumpkin variation

The Original Jen's Juicy Fruit - ∆ 6 glaze from the Michigan Ceramic Art Association website.

JJ variation with Black Iron - ∆ 6
I like this glaze on the tops of my pots. It bleeds well into my iron red variations and grows wonderful crystals in a slow cooling.

Cream Breaking Rust - ∆ 6
A very durable cream colored glaze that breaks to rust over edges. This glaze looks best on iron bearing clay bodies.

Ron Roy's Licorice Black - ∆ 6
A very glossy durable black glaze.
The little bowl to the left was dipped in Ron Roy's Black first and then dipped into cream breaking rust. I didn't have any pictures of just the black on its own, but it is black and glossy.

Majolica Glazes - ∆ 1

Variation one, Variation two, Variation three

There are three variations of this glaze that I use in my classroom. All three variations are shiny, white, durable and stay suspended well in the bucket. When I work with kids, I have them create their pieces using Rovin's RO-82 Terra Cotta clay Then I bisque fire it to cone 04. I dip the bottoms of their pieces into hot paraffin wax in a frying pan and then they dip their project into the white Majolica base glaze. Then at each table in the art room I have a different color of Amaco or Sax lowfire glaze or underglaze. The kids paint these lowfire glazes and underglazes over the top of the white Majolica base glaze. Then I fire these in an electric kiln to cone 1. Amazingly, the lowfire glazes do not run off the pieces at cone 1. Having the kids dip their pieces in a base glaze before adding colors over the top eliminates the glaze misses they have if they brush on only the lowfire glazes. They also do not need to apply more than one coat of the lowfire glazes to get good color and shine.

Most of my work with glazes is towards developing visually rich surfaces. Do not assume these glazes are safe to use in contact with food surfaces. Some probably are and some probably are not. If you plan to use them in that way, please have them laboratory tested for metals release. I have a few glazes I have had tested and know are safe to use on surfaces that come into contact with food. It is up to each individual potter to test the glazes he/she uses because of all of the variables that go into the application and firing of glazes.

In order to replicate my glaze results, you will need to slow cool your electric kiln. You can find my firing schedules for slow cooling on this page. This page also contains an FAQ section with tips for getting my glazes to work in your kiln.