Potter’s crack is not anything like Plumber’s crack. It is more like a Junkie’s crack. Very addictive and makes you feel really high when you get a good batch. I’ve been messing with this crack under shino now for probably 2 months. I’ve had so many lows and very few highs. I think I now have figured it out. Why did I just say that?
The copper red you see is the result of wood ash interacting with the coloured shino I rub into the cracks. I sprinkle the wood ash on with a kitchen screen while the glaze is still wet. I mixed 2% copper into my shino recipe. I also did a blue shino with 1% cobalt oxide.
This is a new frontier for me so results weren’t as instant as I would have liked. I ended up bisqueing the crack to Cone 02. This actually fluxed the surface but it did open the cracks up so that I could rub the coloured shino into the cracks.
This has not been the best of weeks for me with my kiln sitting idle for the better part of a month . This is the second time in a year the damper motor went south on my computerized Geil kiln. I just ltoday sent the motor back south to California. I am very fortunate I have a smart young electrician helping me through all the high tech stuff. Technology is wonderful when it works. When it doesn’t it is very stressful.
My crack tests were fired in my cousin Brenda’s gas kiln. Nice burners that you just light a match and you’re good to go. Mind you, you have to move the damper all by yourself.