Colbalt

[tickled pink]

I wanted to use colbalt oxide or carb. under or over a glaze. Is there something other than water to mix with it to make it better?

[Benhim]

Well the first thing you want to do is decide whether you want it under or over. This would most likely be determined by the glaze you're using, as any glaze with an opacifier is likely going to block most underglaze decoration. I'd also have to know you're firing temperature to provide recipe help. But I can say that cobalt is a very strong colorant and should be diluted to be used. Blue glazes often have .5 to 2% cobalt. This is plenty to give a glaze light blue to bright blue color depending on the glaze composition.

[Marcia Selsor]

Cobalt is a powerful colorant in either state (oxide or carbonate).

It should be mixed in a based for either an overglaze or underglaze. The base recipes would depend on what temperature you are using.

As a wash it can be very diluted.

As Benhim says .5-2% is plenty in a glaze. I have used .2% in more subtle blue glazes.

 

Marcia

[tickled pink]

Well the first thing you want to do is decide whether you want it under or over. This would most likely be determined by the glaze you're using, as any glaze with an opacifier is likely going to block most underglaze decoration. I'd also have to know you're firing temperature to provide recipe help. But I can say that cobalt is a very strong colorant and should be diluted to be used. Blue glazes often have .5 to 2% cobalt. This is plenty to give a glaze light blue to bright blue color depending on the glaze composition.

 

 

 

I will be firing to cone 6 and will do both underglaze and over. thanks for your help on this.

[tickled pink]

Cobalt is a powerful colorant in either state (oxide or carbonate).

It should be mixed in a based for either an overglaze or underglaze. The base recipes would depend on what temperature you are using.

As a wash it can be very diluted.

As Benhim says .5-2% is plenty in a glaze. I have used .2% in more subtle blue glazes.

 

Marcia

 

 

Hi Marcia,

I will be firing to cone 6 and doing both under and over glaze with the colbalt. thanks for your help

[Benhim]

I do slip work under glazes because I like the way it looks in my work and I enjoy working with engobes. 3% cobalt in an engobe gives a good color under most clear glazes.

 

I used to work with a guy who did a 50/50 iron oxide/custer feldspar. He painted on some folk art characters which were rimmed in some white slip glaze. He put a dark green celadon which caused the iron to light up into a mixture of red/brown/black.

 

 

I don't do any over glaze work myself, but I'm sure someone here does it maybe they could comment.

[tickled pink]

I do slip work under glazes because I like the way it looks in my work and I enjoy working with engobes. 3% cobalt in an engobe gives a good color under most clear glazes.

 

I used to work with a guy who did a 50/50 iron oxide/custer feldspar. He painted on some folk art characters which were rimmed in some white slip glaze. He put a dark green celadon which caused the iron to light up into a mixture of red/brown/black.

 

 

I don't do any over glaze work myself, but I'm sure someone here does it maybe they could comment.

 

 

Thank you I am going to try both and see what happens. Wish me luck.

[Rebekah Krieger]

Can I revive this topic as a piggy back off of the other cobalt topic? I am trying to find a basic oxide wash recipe or underglaze recipe for ^6.  I am using amaco's clear glaze (over oxide wash) for now but currently researching this before I work on getting a clear glaze.  I have cobalt Carb, not oxide  

 

I would like to be able to do the same work I am doing but with making my own glaze.