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HELP !! Reduction Firing.

Hello fellow potters of Australia

I am having a few troubles with get the reduction balance right in a cross-draft (Excel) gas kiln.

The problem is this... I am using a copper oxide wash recipe to create purples over a Chun glaze. This in other kilns creates beautiful purples. The reduction seems to be happening beautifully as the clay body is all speckled and rich with iron flecks. But the glaze purples that I hope to see are mostly turquoise, the outcome usually seen in oxidation. So.... the clay body is showing I'm on the right track but the glaze colours are not.

There are a few theories that I've come up with but cant seem to find any info to help me out:

1. I kept the kiln in reduction until the end as this seemed to be a great way to control this really sensitive kiln. I have recently been told that this may be counteractive to the purples created during reduction & that bringing it back in to oxidation kind of completes the transformation or, for lack of a better way of describing, 'fixes' the glaze colours produced during the reduction stage, kind of like a mordant in fabric dying. ?

2. I swapped some of the tin oxide out with zircosil in the glaze recipe as I had run out & tin oxide is freakin expensive stuff. I cant see how this could hugely effect it though as I've used copper just as a wash previous and got purples No problem!

3. I entered reduction a little later than usual at 1050c. I usual go in at 1000 have been told that best reduction colour transformation takes place between 1100-1200.

IF ANYONE has any ideas please let me know ?? your assistance is so very much appreciated. Trying not to waste anymore gas!

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