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vivk

Copper Phthalocyanine In Glaze

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vivk    0

Hi all.

I am quite new to ceramic glazing- still very much in the experimental stage, always looking for alternative pigments. I recently found in my local hardware store a blue oxide powder used to colour cement,

It is an intense blue pigment which I think is copper phthalocyanine. has anyone out there used this pigment in a glaze. I would love to know as I am looking for another blue oxide other than cobalt oxide which is expensive.

Look forward to some replies.

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PeterH    87

Sorry Vivk, but copper phthalocyanine is largely organic, and will just burn out

in a glaze firing, leaving a little copper behind. Regards, Peter

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Chris Campbell    1,086

First off, I want to say how impressed I am with PeterH who knew what this was ... once a chemical gets beyond three sylables I am lost! :rolleyes:

 

Second, to Vivk ... cobalt oxide is expensive but nothing can match that blue!! A little really goes a long way.

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PeterH    87

Chris, Thanks for the undeserved complement. Although I was aware that many/most modern artists pigments

are organic I certainly didn't recognise the name (although I've bought Monastral blue artists paint).

However, the wonder of wikipedia gives:

http://en.wikipedia.org/wiki/Copper_phthalocyanine

... which gives a formula C32H16N8Cu, and even a picture of the molecule/complex

http://en.wikipedia.org/wiki/File:Copper_phthalocyanine.svg

[in chemists shorthand: the unmarked vertices are carbon atoms, and any attached hydrogen atoms are not indicated.]

 

Surprisingly the wiki entry suggests that the complex doesn't decompose until about 600C.

Regards, Peter

 

PS really just a plug for http://en.wikipedia.org/wiki/ as a line of first resort. While I believe it can be a bit iffy for matters

of opinion, it's really rather good for matters of scientific fact.

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vivk    0

Thanks Peter for your response. I did a test firing today and guess what- it burnt off as you said- completely bleached result.Oh well, I tried. I suspect this is the stuff they use in washing powder called "blue" or something like that- makes your whites whiter. Anyway I am still curious as to see what it does if I combine it with other oxides- grind it with say, iron oxide. It must be very volatile and if I could find a way of removing the water from the molecule other than using heat?? any chemists out there who can advise? Or just stick with good old cobalt!

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neilestrick    1,381

There are several reasons we use the metallic oxides we do: they're well tested, non-soluble, inorganic, and familiar enough that we know how to handle them safely. Not to be a bummer, but chances are anything you find at the hardware store will be less than ideal. But if you do go that route, and I think it's great that you're thinking outside the ceramic box, make sure you know enough about the chemicals to handle them safely.

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vivk    0

Thanks for all the advice. Have given up on the phthalocyanine, but recently did a pit firing using copper sulphate (dissolved in pool acid!) and got some interesting results. So I will keep experimenting.

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oldlady    1,323

i bought some copper sulphate and found that it works well but it will not keep in the liquid glaze.  if i remember right it went so stiff as to be a solid after sitting on the shelf mixed into a glaze.

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bny    5

With reference to laundry products, many detergents contain organic brighteners that are organic dyes that fluoresce blue in UV from sunlight. Some old style laundry bluings are Prussian blue, iron bed act an over rate. I would not fire this, guessing that it could release cyanide and would come out brown to black anyway.

 

Other bluings are/were synthetic ultramarine. This is a very interesting substance that is made in a kiln: a zeolite / aluminosilicate that contains a trisulfide ion within a cage. Sadly, what is made by the kiln is also destroyed by it. The sulfur goes away, taking the quantum magic, and thus the color, with it. It would be interesting to see if it could survive some very low fire fluxing environment, maybe with a bit of gypsum added to keep sulfur nearby.

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bny    5

What is more fascinating is the fact that this arose in nature from lapis lazuli, then made its way to synthesis through accidental discovery in a lime kiln.

 

Bluing is an interesting use for a zeolite.

 

I think they're primarily added to to detergent as a water softener, by capturing cations like Darvan does.

 

 

 

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