iron oxide powder

[Sandra Jimison]

Glazing is my nemesis!

 

I would like to get the speckled effect. I would like to get some colorant build up in recessed area. I am using white stoneware clay.

I read is a book, you can do an iron oxide wash, apply it to bone dry greenware, let it dry completely, than brush off with a sponge when it is powder dry, and it will do what I am looking for. Unfortunately what happened is the wash also soaked into the flat areas of my piece and it just looks messy. What did I do wrong?

 

Thanks,

 

Sandra Jimison

 

 

[Matt Oz]

Is this the kind of effect your looking for, I did this on bisque instead of greenware, that may work better for you.

 

[Sandra Jimison]

Matt,

 

Almost. I love the color. Is this a straight wash? Did you add a clear glaze on top? Did you do this in one firing?

 

The only thing missing is the speckles.

 

Thanks,

 

Sandra

[Matt Oz]

Matt,

 

Almost. I love the color. Is this a straight wash? Did you add a clear glaze on top? Did you do this in one firing?

 

The only thing missing is the speckles.

 

Thanks,

 

Sandra

 

I used a straight wash as you described, but after the sculpture had gone through a bisque fire, so it is fired twice. No clear glaze was used, and the clay body is porcelain.

 

If it's dark speckles you looking for, you may need a clay body that speckles on its own, usually because it has granular ilmenite mixed onto it.

 

If you can post a picture, or give a link to the effect your looking for, I'm sure someone could figure it out.

[Kohaku]

Glazing is my nemesis!

 

I would like to get the speckled effect. I would like to get some colorant build up in recessed area. I am using white stoneware clay.

I read is a book, you can do an iron oxide wash, apply it to bone dry greenware, let it dry completely, than brush off with a sponge when it is powder dry, and it will do what I am looking for. Unfortunately what happened is the wash also soaked into the flat areas of my piece and it just looks messy. What did I do wrong?

 

Thanks,

 

Sandra Jimison

 

 

 

 

Sandra- I've used Iron oxide for texture quite a bit, and never obtained a speckling effect when the powder was washed onto greenware. I believe the speckling is a function of the oxide burning through an overlaid glaze.

 

Matt- nice piece.

[Sandra Jimison]

You are right.

I am obviously delusional.

I went back and looked at the picture in the book I mentioned. What this person had done " When the mask was bone dry, a mix of red iron oxide and water was applied over the modeled areas. When this was bone dry, the powdery oxide was brushed off with a dry sponge leaving some of the oxide behind in the crevices. After bisque firing, the piece was dipped in the dry turquoise glaze and high fired in an electric kiln." So yes, the iron oxide is simply burning through the glaze.

 

Thanks for every thing,

 

Sandra

 

[perkolator]

ilmenite added to your glaze will give the speckled effect you are looking for. also, not sieving the glaze after dark colorants such as iron are added, can sometimes have this speckled effect but not always. a third way would be to have the dark under-layers eat through your top layer of glaze, like others have mentioned.

 

as for trying to get your dark colorant to deposit into areas without effecting other areas - you need to play around with technique and timing. greenware will just soak up the wash if you go over undesired areas since the clay is very porous at this state, as you have found. try it on bisqueware or a fired piece that's closer to clay's maturity to prevent absorption in unwanted areas. you could also try it on a piece of greenware that's been burnished and/or still has some moisture left in the clay, both of which may retard the material from depositing in unwanted areas. also, doing this technique on a piece that's already glaze fired can be a way to control the effect. a piece can be fired almost infinitely so experiment with layering and multi-firing.

[SmartsyArtsy]

I love using ilmenite for the speck lying. I have done it with clear glaze, but do not have photos. Here, though is ilmenite in a colored glaze, actually the photo shows with and without. You might want to do an iron wash for bisque, then a clear satin with ilmenite for glaze firing.