[MargaretW]

I glazed two sgraffito platters with a satin clear glaze. When the bisque came out of the kiln today the satin clear glaze did NOT glaze clear. It fired to an opaque glaze and is hiding my sgraffito.

I am a new potter and would appreciate ideas on how to fix my problem. Do you think re-firing them again at a higher temperature would fix my problem? The clay used was 266.

[Mark C.]

MargaretW, on 12 December 2012 - 09:11 PM, said:

I glazed two sgraffito platters with a satin clear glaze. When the bisque came out of the kiln today the satin clear glaze did NOT glaze clear. It fired to an opaque glaze and is hiding my sgraffito.

I am a new potter and would appreciate ideas on how to fix my problem. Do you think re-firing them again at a higher temperature would fix my problem? The clay used was 266.

I assume this is a low fire glaze as you did not mention actual cone temperatures- thickness can be an issue as well as temperature .Does the glaze appear to thick? or is it super thin?
what cone was it fired to ? and what should it be fired to-these all will help with the answers-did you brush it or spray it or pour the glaze?Was it well mixed before applying to the work?
Mark

[SmartsyArtsy]

You say it was a bisque. Did you attempt to single fire?

[bciskepottery]

Standard 266 has a lot (understatement) of iron oxide in the clay body; chances are the iron (or manganese dioxide) in the clay is reacting with the materials in your satin clear glaze and making it more opaque. Getting clears to be "clear" on red, brown, and black clay bodies is hard and you'll probably need to test a number of clear glazes before you find one that works for you. Refiring at higher temperature will not help.

[neilestrick]

I agree. 266 really messes with glazes. In addition, satin clear glazes are not generally as clear as glossy clear glazes.