Blues From Raku Firing

[judithl]

I have been using some very nice commercial raku glazes that are supposed to have blues and greens in them, som e with very delicate pinks. UNfortunately I seem to get coppery colors most of the time. A friend has suggested that my timing between kiln and cobustibles is off, but cant add any more information. ANy suggestions?

[janwallace]

I have been using some very nice commercial raku glazes that are supposed to have blues and greens in them, som e with very delicate pinks. UNfortunately I seem to get coppery colors most of the time. A friend has suggested that my timing between kiln and cobustibles is off, but cant add any more information. ANy suggestions?

 

I have done a bit of raku myself over the years, but only formulated glazes from recipes in books, not bought commercial raku glazes. Seems to me that if your glaze says it produces blues and greens and is producing coppery reds (i assume you are getting red), then your commercial glaze contains copper oxides. In which case, under heavy reduction, copper oxide will produce copper reds and under less reduction/more oxidation you will achieve blues and greens (turquiose glaze). Sometimes both colours on the one pot. There are so many great and very simple raku recipes to be found (on this website too), that i would recommend you try some. They work out to be very inexpensive to make too compared to purchasing commercial ones. Have fun experimenting, that is part of the fun!

[HAUKSBEE]

I agree with janwallace, less reduction, more oxidation.

[Guest JBaymore]

I have been using some very nice commercial raku glazes that are supposed to have blues and greens in them, som e with very delicate pinks. UNfortunately I seem to get coppery colors most of the time. A friend has suggested that my timing between kiln and cobustibles is off, but cant add any more information. ANy suggestions?

 

 

Let the piece cool well off between pulling it from the kiln and getting it into the combustables. Simple fix. It still will get the body and any craze lines impregnated with carbon, but the glaze will be below the reactive temperature for the CuO getting reduced to Cu.

 

best,

 

................john

[Seasoned Warrior]

I have been using some very nice commercial raku glazes that are supposed to have blues and greens in them, som e with very delicate pinks. UNfortunately I seem to get coppery colors most of the time. A friend has suggested that my timing between kiln and cobustibles is off, but cant add any more information. ANy suggestions?

 

 

I find that a lot of time if one uses commercial glazes you don't really have good control of your process. I like to know what is in the glaze so that I can determine what part of the process is not functionoing the way I want. Try what was suggested and make up some of your own glazes from published recipes. I like to search for glaze formulas from educational institutions; many of them have excellent glaze recipes (Augusta State University for one) and they are readily available. As in cooking I like to start off with a baseline recipe that I know works and then vary quantities of individual constituents to see what happens. I like to do a lot of testing before I settle on something I actually work with.

 

Bes regards,

Charles

[Marcia Selsor]

I have never used commercial raku glazes..but I agree with previous commenters. Try letting them cool a little before putting them into the combustion material. If you are getting coppery colors, you're getting a strong reduction in the combustibles.

 

-Marcia