New Engobe

[Benhim]

I've just started working with a new engobe and wanted some guidance as to how much colorant to use for different colors. I'm looking for a green, yellow, red, black, blue and any other safe color I can make.

 

Here is the new engobe recipe I'm using as a base, it's from Zakin's book where I've gotten many of the recipes I'm using currently in my studio.

 

Cone 6

Nepheline Syenite 24

Flint 18

Boron Frit 6

Kaolin 36

Dolomite 10

Zircopax 6

 

 

I have many of the traditional colorants, Iron Oxide, Manganese Dioxide, Cobalt Carbonate, Chrome, Titanium Dioxide, Copper Carbonate. I'd like to stay away from Manganese Dioxide as much as possible because of the probability of leaching as this will be used on both functional and non functional ware.

 

Thanks

[bciskepottery]

Attached are some recipes I use for colored slips/engobes attributed to Cynthia Bringle. The base recipe is the same; however, various potters have taken different approaches to colorants. It is pretty much trial and error until you get the color/hue that you like.

 

 

[Benhim]

Thanks for that, it's quite interesting. I've never seen colorants used like NCSU. I've only used 10 - 20% in an engobe. Any idea of what that much iron, chrome, or rutile will do under a base clear glaze? I can imagine in the salt/soda those would be dark colors.

[bciskepottery]

I've only used the Bringle Slips during a salt firing for exterior decoration; no clear overcoat, just slip on the clay body. So, I was not worried about leeching or anything like that.

 

If used for a food surface, I'd have to recommend having testing done. That is the only way to find out for sure. But, given the percentages of some (manganese oxide and cobalt carbonate in black, for instance), , I can pretty much guess they will come back not suitable for food surfaces.

[Benhim]

I've only used the Bringle Slips during a salt firing for exterior decoration; no clear overcoat, just slip on the clay body. So, I was not worried about leeching or anything like that.

 

If used for a food surface, I'd have to recommend having testing done. That is the only way to find out for sure. But, given the percentages of some (manganese oxide and cobalt carbonate in black, for instance), , I can pretty much guess they will come back not suitable for food surfaces.

 

 

Great thanks, most of what I'm doing is going to be decorative, but I'd like to have some safe mixtures as well.