Converting Reduction Temmoku To Oxidation Firing

[Mart]

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	45Silica	27Whitining	17Kaolin	11Red 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

[ayjay]

Custer Feldspar	45Silica	27Whitining	17Kaolin	11Red 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.

[phill]

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

[Mart]

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

[Denice]

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

[Wyndham]

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

[neilestrick]

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....

[Mart]

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.

[jrgpots]

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

[Bob Coyle]

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

[Biglou13]

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

[Mart]

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.ne.jp/kenyou/eindex3.htm)

• Honan = Brown and Black
• Yohen = literally, Stars Glistening in a Night Sky, where each spot is iridescent in color
• Bizen = Hare’s Fur
• Yuteki = traditional Oil Spot
• Haikatsugi (ash covered, often applied over a yellow underglaze – http://www.miho.or.jp/booth/html/imgbig/00005410e.htm)
• Taihisan or Taihi = Tortoiseshell (http://www.kyohaku.go.jp/eng/dictio/data/touji/tenm03.htm)

(from http://prometheanpottery.wordpress.com/tag/ems-tenmoku-glaze/)

 

 

Here is more tenmoku examples http://www.oostuudio.ee/tenmoku-espresso-topsid/img_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)

[Biglou13]

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.  

[Mart]

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

[Biglou13]

Thanks those all work and have been bookmarked

[Wyndham]

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