Give Me More Crackle!

[wenders]

My fellow rakuteers and I have been having inconsisent results with a long-trusted white crackle glaze, whether on a cone 6 white stoneware or a classic grog rakuware. I think the problem is primarily the glaze temperature (we usually (electric) bisque to 08), and always aim for 1000C degrees in our propane kiln, having achieved some fantastic crackles, mattes, and lustres. In all the material I've seen for raku glaze recipes and reduction techniques, I've rarely seen anything about temperature for glossy v. matte. I seem to recall one workshop where we were told to fire the crackle-glazed ware farthest from the flame and/or to a slighty lower temp. While I thrill at the unpredictability of raku, there's a certain level of stability that would be equally thrilling! Any suggestions?!?

[Chris Campbell]

Are you looking for more crackle or are you trying to find a matte?

 

I fired white crackle glaze by sight ... When it looks like water melting on ice it is ready to pull.

Not very scientific.

 

Then hold it in the air until you hear the first ping.

Then cover for reduction.

[Mike@riverrun]

My fellow rakuteers and I have been having inconsisent results with a long-trusted white crackle glaze, whether on a cone 6 white stoneware or a classic grog rakuware. I think the problem is primarily the glaze temperature (we usually (electric) bisque to 08), and always aim for 1000C degrees in our propane kiln, having achieved some fantastic crackles, mattes, and lustres. In all the material I've seen for raku glaze recipes and reduction techniques, I've rarely seen anything about temperature for glossy v. matte. I seem to recall one workshop where we were told to fire the crackle-glazed ware farthest from the flame and/or to a slighty lower temp. While I thrill at the unpredictability of raku, there's a certain level of stability that would be equally thrilling! Any suggestions?!?

 

[Mike@riverrun]

I second the eyeball method. The glaze should look like sun reflecting off water melted on top of an icy pond. If you are reducing in paper or sawdust are you leaving it in there too long? I get better cracks if I plunge into water after about 15 min in reduction. The amount of cracking also relates to the glaze fit. Post the recipe, there may be clues.

[Marcia Selsor]

My fellow rakuteers and I have been having inconsisent results with a long-trusted white crackle glaze, whether on a cone 6 white stoneware or a classic grog rakuware. I think the problem is primarily the glaze temperature (we usually (electric) bisque to 08), and always aim for 1000C degrees in our propane kiln, having achieved some fantastic crackles, mattes, and lustres. In all the material I've seen for raku glaze recipes and reduction techniques, I've rarely seen anything about temperature for glossy v. matte. I seem to recall one workshop where we were told to fire the crackle-glazed ware farthest from the flame and/or to a slighty lower temp. While I thrill at the unpredictability of raku, there's a certain level of stability that would be equally thrilling! Any suggestions?!?

 

 

I agree with Chris, fire by eye until you get to know the glaze. Wave it around in the air or even have someone squirt it with water before smoking it. The shock causes the crackles.