contaminated kiln elements HELP!!!!!!!

[racheluk]

Hi All my name is Rachel and I have got a problem with my very large
oval Olympic kiln I think its the largest kiln they make not sure if
this will be relevant or not just wanted you to get the size of the
possible problem which is.........


I make ceramic torso's life size and have always used a bronze glaze for
them, I also dabble in Egyptian paste containing Copper Carb and Soda
Ash the egyptian paste I have always fired in my test Kiln with out any
problems arising or any adverse effects of other glazed bodies.

I decided to make a torso in Egyptian paste and made 2 life size casts
and fired them in my Olympic electric Kiln all went well until I needed
to fire some bronze torso's some weeks later and the bronze glaze came
out near black with a glitter effect, shocked at the results I did fire
another 2 torso and got the same black results I did test the Bronze
glaze first in the test kiln and all was well

I presume now that the kiln is contaminated as the Egyptian paste was so
large not sure if it was the copper or the soda ash my question is how
do (if I can) counteract the damage or will it diminish with time or
maybe take the kiln to stoneware and hopefully burning off the damage or
is it new elements, if I replace the elements will the bricks/shelves
etc still be contaminated.

Happy New Year to everyone
Rachel

[tbobker]

Im not sure that contaminated elemet can put black marks onto your work, especially if its copper.
It sounds like carbon is soaking in, maybe something is burning at the back. Contaminated bricks certainly wont do any harm, glaze will just melt and drip down but never jump for the side to your work....
The clitter effect sounds like the bronze just showing through or mixing with the carbon. SOunds pretty nice actually i would be happy with it if it looks how i see it!

Look at the elements and check the back for smoke when it is on.

[GT3000]

Wasn't it a happy accident then, it doesn't sound as though it looks bad. Any pictures?

[toppotter]

Hi, personnaly I don't think your elements of brick work is contaminated.

Hi, personnaly I don't think your elements of brick work is contaminated. Rember that different thickneses of your glaze will givedifferent results. Also the finnished apperarance of the glaze will be affected by the rate of cooling, very fast in your small test kiln, more slowly in your large kiln, which may allow some crystals to grow in the glaze giving a different look.
Maybe next time try two tests in your large kiln one with a single layer of glaze and one with two or three layers of glaze. Can i ask, did the eygptian paste get onto the kiln shelf? and by the way you didn't change the type of clay from the one you used in the test?

regards
Robin