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Ground Breaking

Reuse, recycle, reduce. We hear these ideas all the time and I tend to think they are good ones. It comes in especially great when someone gives me an old kiln.  That is exactly what happened when the electric kiln that we used for cone 6 glaze firing gave up the ghost at Callanwolde. It’s a good size kiln, much bigger than my electric kiln but I’m not interested in rewiring this one. You may remember I did that with my electric kiln when I installed the kiln sitter (you can read about that here) which I got from another free kiln.

My plan for this kiln is to make it a reduction kiln since that is the look I like best for my pots. I am even considering adding a stoke hole so I can feed some small piece of wood into the kiln for some ash and wood effects.

Before I can start converting it into a gas kiln I need to build a kiln shed. My current kiln room is fine for the electric kiln but it’s too crowded to add flame to the mix. I’m designing a simple lean-to type shed that will have a m…

Better Kiln Wash and Wadding Recipe

After last weeks article about loading the soda kiln I received a few questions about kiln wash and wadding. Instead of answering each one individually I thought I’d just answer them all here. Feel free to add any other questions or information in the comments.

Pots in a Salt Kiln (wadding is circled)
Kiln Wash is basically a combination of Alumina Hydrate, EPK, and water. Potters paint this on the kiln shelves to help prevent pots from sticking too the shelves. If glaze runs while the kiln is firing it can bond to the kiln shelf just like it bonds to the pots. Alumina Hydrate is highly refractory which, in simple terms, means it helps to prevent the bonding from happening. For a more scientific explanation of a refractory see the “Other Stuff” section below.

Wadding is made of the exact same ingredients as kiln wash but with much less water so it’s more of the consistency of clay. It’s got the same refractory properties as the kiln wash but it is usually only used in atmospheric firings where something is added to the atmosphere of the kiln that will create a glaze (wood, salt, and/or soda). Since the glaze is created by introducing something to the atmosphere it tends to glaze everything in its path so we put small pieces of wadding under the pots to prevent them from sticking to the kiln shelves. This allows the glaze to flow under the pot also so you can get an almost fully glazed piece.  Since the glaze doesn’t land on the pot wherever the wadding is some potters use it to help create beautiful design effects. Some potters will add combustibles like sawdust or coffee to wadding often for esthetic reasons.

When I was at Penland School of Crafts we used Cynthia Bringle’s recipe for wadding and kiln wash. The recipe uses less Alumina Hydrate, the more expensive ingredient, therefore it costs a little less to make. We fired about 2000 glazed pots in many salt and soda kilns. I promise it works just as well as the 50/50 mixture I’ve always used.

Kiln Wash and Wadding Recipe:

70% EPK
30% Alumina Hydrate
Enough water to make it the consistency of the application you desire. If you use too much water it can be dried out via evaporation or on plaster.

Other Stuff:

Definition of Refractory - https://en.wikipedia.org/wiki/Refractory
Alumina Hydrate - http://dictionary.reference.com/browse/aluminum+hydrate
Edgar Plastic Kaolin and other raw materials - http://lakesidepottery.com/HTML%20Text/Tips/Glossary%20of%20Ceramic%20Raw%20Materials.htm

Check out the gallery page - Future Relics Gallery by Lori Buff

Comments

  1. there is so much I don't know about all the chemicals; I learn every day, great post

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  2. wow, those pots were packed in extra tight weren't they?

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  3. That is basically the recipe we use for wadding too. We have fired with a few people who add sawdust or flour to the mix. I really don't like it. The wads seem harder to take off and they often leave speckles instead of white dots on the bottoms of pots.

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  4. I do 1 part alumina hydrate, 1 part kaolin, 1 part coffee grounds. Makes the wadding softer so it grinds away more easily...you know I love those rivers of soda!

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    Replies
    1. I’ve heard of people doing that and may try it sometime. It’s a good way to get rid of those used coffee grounds and the wadding should smell good.

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