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Looking For A Gray Glaze (Picture Included)

glaze stoneware oxidation

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#1 Mart

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Posted 22 November 2013 - 12:47 PM

I am looking for a good "dark" grey glaze I can fire in oxidation on light stoneware clay. We wire around 1249C (cone 9)

This the tone (or shade) of grey I am looking for (forget it's b&w image):

Attached File  gray-clay.jpg   22.2KB   3 downloads

Do you have any good recipes?

 

I am thinking about experimenting with white satin glaze I have and adding some black stain I got (Co-Fe-Cr). Am I even on the right track?



#2 Mart

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Posted 22 November 2013 - 05:29 PM

Norm, thank you for your advice. Sounds like I need very specific base glaze to get the final result I need.
BTW, I have no idea what Zircopax and Gerstley Borate are. Must be brand names for something. I'll google it. :)

Closest place to get some Mason stains (really good stuff, btw) is UK. No problems, I can order from there.

Other black paths to grey develop funny overtones of purple, green, brown, orange etc.

 
Oh no! Not purple. Purple is one of the most disgusting shades of colour ever. Especially in ceramics. I hope I never screw up any glaze to end up with purple. brrr.... horror!

#3 Mart

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Posted 23 November 2013 - 04:14 AM

Here is another example of really nice grey.

Attached File  grey-2.jpg   14.2KB   0 downloads
 
Maybe I am going at it the wrong way. Maybe I need to add stains to my clay or use grey engobe and really thin layer of glaze.
 
From local shop, I can get:
1) grey 161 (Zr-Ni-Co-Cr-Fe-Zn)
2) grey 156 (Zr-Co-Ni)
3) grey 3108(Sn-Sb)

They probably have none of those in stock, so I'll get my stuff faster by ordering from UK and going with Mason stains.

#4 Marcia Selsor

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Posted 13 January 2014 - 06:50 PM

Mart,
Mixing a Black Glaze with a white glaze will work IF they are the same base recipe.OR you could mix your white glaze and add a small amount of Mason 6600 Black following reference code.. By small I mean somewhere between .5 to 1.5 %. You may need to do tests in .5% increments to find what you want.
I have used Nickel Carb. and cobalt, Iron and cobalt, Iron and Nickel, Copper and Nickel, Manganese and Nickel to get grays.
Try some color blend tests #1=base with rutile 1-2%% in the base or not ,#2 maybe Nickel 0.5-3%,#3= Iron 1.0-5%, #4=copper carb.2-6%, #5=manganese .5-3%
#6=cobalt carb. try .5 up to 1%

If out of these 21 tiles you see potential, try refining the color you desire. And try again.
1,2,3,4,5,6
1-2, 1-3,1-4 1-5, 1-6
2-3,2-4,2-5,2-6
3-4,3-5, 3-6
4-5 4-6
5-6
The results will depend much on your base. Find a base with the texture you are after.Use texture on your test tiles to show breaking (color variation)tendencies,
Marcia

#5 Biglou13

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Posted 13 January 2014 - 10:28 PM

Mart are you also looking for it to be matte?
Caution big brother is watching.
The beige is blinding!!!!!!
The middle of the road is boring

The true sign of intelligence is not knowledge but imagination.
-Albert Einstein

#6 Mark C.

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Posted 14 January 2014 - 12:05 AM

Mart

That pitcher looks to be reduction fired with the iron burn outs.

I used to make dentists spit bowls in a cone 10 shark skin grey -it was shiny-I had a very stable white base glaze and added the mason stain 6600 that Norm spoke of. This was back in the 80's when I had a small whole sale thing with a dentist cabinet maker . I shipped these to them in various colors and as a cone 10 porcelain product they like the hardness of them.-They plumbed the rotating water supply so they washed the spit down the drain. They all had to be sized to fit their drain specs.

It was the easiest to get a good grey color with stains-Looks to be the same today.

If you have no mason stains Marcia has spelled all your choices out well above

For me I had a great white base so mason stain only added the color I needed and was so easy to do test blends till I got what I needed.

 

Good luck


Mark Cortright
www.liscomhillpottery.com

#7 Marcia Selsor

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Posted 14 January 2014 - 09:44 AM

Tests are still required to nail the color you want.And you will learn a lot from doing a series of tests. Since we don't know your clay body, the chemicals in your shop, you need to come up with the base. If you are using a stoneware, you might get what you want using gray celedon recipes.

Marcia

#8 timbo_heff

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Posted 14 January 2014 - 03:03 PM

 

Gerstley Borate is an inexpensive locally-produced (California) self-suspending low-fire clear fluxed with Boron.

Sorry Norm but this is not true at all: and very very misleading:

Gerstley is a mined conglomeration of minerals "...an aggregate of minerals and therefore it has qualities that cannot be duplicated by frits. GB form in evaporite basins where water and sediments collected. The ore mainly contained the minerals Colemanite (Ca2B6O11 : 5H2O), Ulexite (NaCaB5)9 : 8H2O) and Hectorite. " "...A thick layer of pure material will run right off the ware at cone 06 producing a glossy completely transparent glaze."

http://digitalfire.c...escription.html







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