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Converting Reduction Temmoku To Oxidation Firing


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#1 Mart

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Posted 18 November 2013 - 06:09 AM

We fire our stuff around cone 9+ and we have a electric kiln.

Here is a Temmoku glaze recipe for reduction atmosphere:

Mark's temmoku

Custer Feldspar	45
Silica	27
Whitining	17
Kaolin	11
Red Iron Oxide	10

(sp gr 150)

Can this be converted for oxidation atmosphere? How?

Reason I like this is it's almost black. I like deep dark/black shiny temmoku. Red thin brown is not what I am looking for :)



#2 ayjay

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Posted 18 November 2013 - 07:22 AM

Custer Feldspar	45
Silica	27
Whitining	17
Kaolin	11
Red Iron Oxide	10

(sp gr 150)

Can this be converted for oxidation atmosphere? How?

Reason I like this is it's almost black. I like deep dark/black shiny temmoku. Red thin brown is not what I am looking for :)

I don't know the answer:  but I plan to follow this with interest, it's something I've just begun to research myself.

 

I don't want thin red brown either, but some breaking over corners etc. would be nice. B)



#3 phill

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Posted 18 November 2013 - 07:49 AM

I know our studio temmoku turns deep dark green, almost black, in oxidation. looks great! have you tried it in oxidation yet?



#4 Mart

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Posted 18 November 2013 - 08:06 AM

phill, no I have not. I rather not make a glaze I can not use. :)

#5 Denice

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Posted 18 November 2013 - 09:00 AM

You can make as little as 50 grams by  cutting this easy  formula in half, I hate waste but testing is something you have to do.  I test a glaze on a small tile and if I think it's a glaze I will use I will make up a bigger batch and test it on a pot that has problems like a crack or chip.  Denice



#6 Wyndham

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Posted 18 November 2013 - 09:37 AM

Testing is needed but you may also want to lookup some Kaki glazes to test in electric as they have bone ash as an ingredient that gives the character you might like.

Wyndhamn



#7 neilestrick

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Posted 18 November 2013 - 10:30 AM

You may need to increase the amount of iron oxide to get the darkness you want. You may also need to flux it out a bit more, since the reduced iron contributes to the melt. Test, test, test....


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#8 Mart

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Posted 18 November 2013 - 03:59 PM

Am I correct to say that red iron oxide will turn back in to red again if cooling is too slow?

Thanks Norm, I'll replace red (Fe2O3) with black (FeO) in a small patch and see what happens.

BTW, the one we use right now, has mostly Fe2O3 and tiny bit of black.

#9 jrgpots

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Posted 19 November 2013 - 01:44 AM

Norm, you suggest that extra red iron oxide that remains after firing might be the reason for the red hue. Does that mean that by reducing the amount of RIO one could get a better/darker color or did you just mean that extra time is needed to reduce the RIO?

Jed

#10 Bob Coyle

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Posted 20 November 2013 - 11:40 AM

Here is a glaze that works for me it is a deep chocolate brown with reddish flecks.  cone 5-6 oxidation shiny... holds well on vertical surfaces of  MR5 and B-mix

did not test for absorption.

 

Flint -  25

EPK-  17

Neph Sy - 17

Gertsley -8

Dolomite - 8

Talk - 8

Bone Ash - 7

RIO -10



#11 Biglou13

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Posted 24 November 2013 - 02:55 AM

I'm surprised no one has a cone 6. Alberta/albany based glaze?
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#12 Mart

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Posted 24 November 2013 - 04:58 AM

Looks like the whole Tenmoku business is more complicated but this is for another topic.
 
Types of Tenmoku
(for images, see http://www.est.hi-ho...ou/eindex3.htm)(from http://prometheanpot...tenmoku-glaze/)
 

Here is more tenmoku examples http://www.oostuudio...g_2399_v1/#main
Those are tiny espresso cups I made

My original question was, how (or is it even possible) to convert that recipe so it works in oxidation, around 1249C (cone 9). I like the way it looks. It has very little of red/brown and is more like deep dark shiny piano paint.

Actually, converting is not necessary if you have something else that does not depend on USA specific ingredients and works in 1249C range (about cone 9,oxidation)

#13 Biglou13

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Posted 24 November 2013 - 09:38 AM

mark back to OP (original post)....   no i dont think you can convert that recipe to electric.   reduction is the KEY.   however i do think it is possible to find a make a glaze that is similar, an new formualtion not a RE-formulation   in the few experiments ive done. Iron oxide in oxidation never look like iron oxide in reduction.  like mart said the chemistry is is not the same.   and there is no replacing wood fired  effects.

 

 

the amaco cone6 (which i unfortunately paid for)  became a an under layer, i found it flat and boring.....  definitely not a tenmoku.  with this one i think they are way overstepping the boundaries of name usage.      i can appreciate the gaijin versions of japanese glazes  but this is not in same ball park.

 

this raises a whole nother topic, off topic from orginal post... "american shinos"  aka gaijin shinos   vs japanese shino...   gaijin temoku vs.............

 

the reason i mentioned albany, alberta  is ive seen recipes where people say its tenmoku LIKE. and they looked more like the "japanese tenmokus" ive seen on  the internet.

 

norm... im interested in your albany/alberta slip recipes please pm me.

 

mart please send me above links   they dont seem to work.  


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

The true sign of intelligence is not knowledge but imagination.
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#14 Mart

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Posted 25 November 2013 - 12:17 PM

mart please send me above links   they dont seem to work.


Strange. All those links point to correct sites and work. Here are handmade links, just for you ;)

...for images, see www.est.hi-ho.ne.jp)

...Haikatsugi (ash covered, often applied over a yellow underglaze – link)

... Taihisan or Taihi = Tortoiseshell www.kyohaku.go.jp

#15 Biglou13

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Posted 25 November 2013 - 12:54 PM

Thanks those all work and have been bookmarked
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

#16 Wyndham

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Posted 25 November 2013 - 04:17 PM

Electric cone 9-10 will need overlapping glazes , some more breaking/running over stiffer slip based glazes to re-create a similar or even better look than cone 9-10 temoku. Oil spot glazes would be a good area to start exploring because of the movement of these glazes. As in my other post, bone ash, kaki type glazes  can add to the texture that can be pleasing and possibly  used under or over slip glazes for what you are looking for.

There might be some cone 6 temoku electric that might overlap well.

Wyndham






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