Chrome Fugitive In Kiln?

[Babs]

If chrome, or other colourant, is  placed in a bowl in kiln whilst firing glazes does this effect continue in subsequent firings resullting in unwanted effects? I.e. does it stuff it up for future firings?

[Celia UK]

I've only ever had contamination in the same firing - and only from cobalt carbonate, which seems to be the most fierce 'oxide' in my experience.

[TJR]

Babs;

I concur. If you have a white matt glaze that uses tin as an opacifier, and you have chrome somewhere else in the kiln, but close to your tin glazes, you will get a pink blush.

Only for that fireing, as the chemical reaction is finished.

TJR.

[neilestrick]

I have heard of kilns being contaminated with copper from heavy use with copper glazes. Never seen it in person, though. Could be folklore.

[Babs]

Ok, so i have a very old kiln with the bung holes on the sides as the only venting, and the odd crack on the lid. Still seem deemed that the metals are vaporising and leaking out. At what temp does this vaporization of chrome occur?

[Pres]

Back in the 90's I experimented with some tin oxide or Chrome oxide washes over glazes. I gave me some interesting if inconsistent effects. In the long run, I decided to just use the oxides as inglaze over white glaze. I do have some white glazes that use tin and another oxide as opacifiers to minimalize, but still use the blush effect.