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Week End Puzzler Any Guesses

glaze colourants

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#1 Babs

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Posted 28 February 2014 - 07:33 PM

I have a number of jars acquired from various sources, some unlabelled.

i am trying to establish what they contain.

I did a test tile, ignore lumpy glaze a rush jobbie, the glaze is a C03 Majolica.

I had two known and 3 unknown. Nos. 1 nd 3 are cobalt carb and ritle, dark, flour respectively, No. 2 looks like rutile?? but can you help with the guess.... or any further tests I can do.

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#2 Babs

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Posted 01 March 2014 - 03:06 AM

Too hard, not enough info?

No 2 in fact all were mixed part volume equal with gertsley Borate, then water added and applied to the raw Majolica, the colour is a ligh pink/beige 

WOn't hold anyone responsible for a guess!!

Thinking light rutile, htough  the pinkish tinge suggests chrome.. but the powder is a darkishbrown  

any othe test suggestions, don't really want to chuck this out as colourants are getting more expensive.



#3 Chilly

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Posted 01 March 2014 - 04:40 AM

Friday night/Saturday morning.  They're all still asleep !


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#4 High Bridge Pottery

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Posted 01 March 2014 - 05:02 AM

Iron!

 

I should be asleep... just finished work  -_-



#5 Pres

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Posted 01 March 2014 - 08:34 AM

Yellow Ochre.


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#6 Chris Campbell

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Posted 01 March 2014 - 10:11 AM

Oh Babs!
You are heading down the slippery slope of getting an absolutely fabulous result with no idea of what got you there.
Enjoy !! : - )

Chris Campbell
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TRY ...   FAIL ...  LEARN ...  REPEAT


#7 Min

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Posted 01 March 2014 - 01:12 PM

Is there tin in your majolica?



#8 Bob Coyle

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Posted 01 March 2014 - 02:41 PM

I'd go along with Prez and guess Yellow Ocher.



#9 Babs

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Posted 02 March 2014 - 01:16 AM

Oh Babs!
You are heading down the slippery slope of getting an absolutely fabulous result with no idea of what got you there.
Enjoy !! : - )

sounds like my life :)  Ready to pick up and start the next test.

I'll keep testing, the powder is nowhere near the colour of yellow ochre. Got some of htat so I'll test it alongside the unknown

THe glaze uses tin amd zirc.

Powder doesn't resemble chrome oxide but are there othe r oxides of chrome which are a brownish colour.



#10 Biglou13

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Posted 02 March 2014 - 05:46 AM

I'm with Chris
Sorry to be a downer but I'd throw them all away. Lest you fall in love with...then can't repeat.
Unless chasing ghosts is you're desire
Enjoy your mystery bottles, don't get attached
Better would be to ask how do I make these, try and copy them.... Test test test.
I'm sure someone here will set you in right direction
At least it's repeatable. PPP

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The beige is blinding!!!!!!
The middle of the road is boring

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#11 Min

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Posted 02 March 2014 - 08:52 AM

I'm guessing a low grade of Burnt Umber. The raw colour is dark brown, it contains manganese so that would account for the pink/purple tinge.

 

edit: I would keep the cobalt one, no doubt about that, and toss the rest. 



#12 C. Banks

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Posted 02 March 2014 - 09:48 AM

Hey all,

I'm with Chris and Biglou.

Beautiful mystery glazes are indeed ghosts that will haunt you for years and eat through time and supplies while adding to ever growing limited edition buckets

But...maybe just one more line blend...

:)

my guess is rutile(tio2) though I have no experience with majolica. I do know that tio2 + zno2 + sno2 will show pink tinges but the effect is dependent on glaze thickness.

sorry I don't have more to add other than a shared interest in glaze adventures.

*and with Min re. manganese and maybe keeping the cobalt
"All this of Pot and Potter — Tell me then, Who is the Potter, pray, and who the Pot?" (Omar Khayyam)

#13 Babs

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Posted 02 March 2014 - 07:15 PM

Hey all,

I'm with Chris and Biglou.

Beautiful mystery glazes are indeed ghosts that will haunt you for years and eat through time and supplies while adding to ever growing limited edition buckets

But...maybe just one more line blend...

:)
 

The potter's grail, just one more test!

Already have  a beautiful glaze with this mystery powder,  used because I thought it was cob.carb as labelled, but know that I'd better mark the pots limited editions! 

Going to do some more tiles with this powder against knowns. By which time, hey I may not have any left and still searching :)



#14 jrgpots

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Posted 03 March 2014 - 07:18 PM

How about Erbium oxide (Er2O3) ?  It produces a nice pink color at concentrations from 4% - 10%.

 

Jed



#15 Babs

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Posted 05 March 2014 - 04:42 AM

How about Erbium oxide (Er2O3) ?  It produces a nice pink color at concentrations from 4% - 10%.

 

Jed

Yes, I googled as you suggested. L Arbuckle describes it as a pink powder which this is not. Also says it needs 8-10% in a glaze. I'll keep testing and reading till I can/cannot decide but in the mean time I will treat it with caution.

Thanks for the lead. Great L Arbuckle handout on colourants.

http://lindaarbuckle...-opacifiers.pdf






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