silica carbide and lava glazes

[Lynettes]

I would like to make a lava glaze that fires to cone 9. I would appreciate some advice. Can I use any glaze and add some silica carbide ( how much)? I have seen amy lava glazes for up to cone 6, but not above that.

 

Thanks in advance.

 

Lynette

[Lynettes]

i'm going to go out on a limb here and say that's a definite maybe.

 

iirc i tried amounts less than 1% with a volcanic ash base at ^8-9 in oxidation. the result was more sponge toffee than lava.

 

apparently particle size can seriously affect the outcome

 

*from what i read fine particle size can encourage localised reduction but i put silicon carbide down at sponge toffee.

 

 

 

 

I realized after I asked this question, that, it will not work with any glaze, because I have used it tocause localise reduction and that glaze did not crater. Ther must be a certain chemistry that is necessary, but I havn't been able to find much information about high fire crater glazes.

 

Lynette

[Avaviel]

My teacher obtained it from an industrial type place... something to do with glass.

 

I'm doing some tests now. We're doing them as an addition to the slip – not the glaze. He recommended an addition of around 6%. In the tests, they range from 2% to 12%. I also did mixes with other glazes, to see what happens.

 

 

edit: I found a link to a rock tumbler website, http://rocktumbler.com/grit.shtml They have the type that we used, the coarsest grit.

[Avaviel]

Ok, so I did a few test glazes @ cone 10 with a cratering slip. It didn't do anything, as a slip or a glaze... in any of the tests. This particular example was dipped in slip that had the SC, bisqued, and then glazed.

 

I have a feeling that we had the wrong material, though. I'll find out the next time I'm at school.

 

Ceramics by avaviel, on Flickr