Oxides Affecting Satin Finish?

[clay lover]

I am working on finding a base glaze that has a satin finish that I can use different oxides with to get different glazes. Do some oxides flux a glaze more that others? All my attempts at blue are coming out shiny.

Does the iron in dark red and brown clays flux glazes that are used over them?

[High Bridge Pottery]

I was reading a bit about iron yesterday. It seems it can act refractory in low alumina glazes but also act as a flux in low flux glazes. I would think that each oxide acts differently in a glaze.

 

"Chemically, iron is amphoteric like alumina. Fe2O3 generally behaves as a refractory antiflux material in a glaze melt, combining with alkalis. Oxidation iron-red glazes, for example, can have very low alumina contents yet do not run off ware because the iron acts like alumina to stabilize and stiffen the melt. However these glazes likely will have somewhat reduced durability.

-In glazes low in flux it can behave as an alkali, combining with silica"

[oldlady]

if you work at cone 6, try some of the Wettlaufer glazes in his book "getting into pots"  from the 1970s.  he lists maybe 6 glazes, some shiny, some matte and one described as waxy.  i found that one to be an excellent purple with the addition of Pansy purple mason stain.  have tried several other stains in it and they worked well. 

[Bob Coyle]

I have a nice semi matte (satin) base glaze I use with 0.5 % cobalt carb. When I tried it with  3% copper carb it goes more matte. with 3% RIO it becomes shiny. RIO can be a flux at cone 6 temperatures. Probably the semi matte glazes I formulate are right on the edge anyway. It's a lot harder to get a stable satin than a shiny glaze. If you are on the edge then any additive will probably change the surface texture.

[Mark C.]

colorants do affect the flux and a satin matt is a are glaze to begin with.

You just have to test test test.

Mark

[clay lover]

I know, I know, I know