Wali Hawes 1952 - 2014
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Pottery Help

I'm often asked for help - and I'm happy to give it. These are some of the questions I have been asked about various things.

Reduction for Spanish Lustre Firings

Purvi asks:

Dear Wali,

I would like to go over the process of the firing ..please advise .. Fire to 1000 deg .Then seal the kiln ,chimney ,the air section of the burner . When the kiln cools to 700 deg .switch on the gas(will switch on one burner as advised by u ) ..when there is a blurp sound ..switch off the gas and then switch on again ...(this means that the kiln has to be sealed even when i switch on the burners at 700deg??) should i open the chimney when i start the burners again at 700 deg??? When temp rises to around 750 switch off gas and seal the kiln totally again.

Regards Purvi

Wali Answers:

Dear Purvi,

After reaching temperature, yes you should seal the kiln, meaning burner ports and primary air inlets. There is no need to close off or seal the chimney.

Yes, when the kiln cools to 700 you then open the gas. The gas will re-ignite given the temperature inside the kiln but the type of combustion that goes on is akin to "cracking".

It is a very strong reduction and alot of CO is given off. Seeing your kiln is outside you should have no problems about ventilation.

Use the gas pressure and damper to maintain temperature to not more than between 700-750C. Maintain this for at least 30 minutes though depending on the results you want 45 mins or even one hour is OK.

Good Luck

Wali

 

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