Reliable Cone 6 Temmoku Glaze Recipe Oxidation

[Joseph Fireborn]

Awesome stuff. Mountain Meg has anything in here helped you? Lots of good information for creating a tenmoku.

[Joseph Fireborn]

Update:

 

Original Tile for Reference with the 1742F 1 hour hold:

 

 

Most successful modified tile: 

 

 

As you can see the crystals are very much the color I want. Plus they are in places that I want them to be and not directly in the middle of the tile. The only issue is that the black is not very solid over the whole tile. But at least it is getting to the spot I want it to be. Further batches need to be made.

 

I added 7% bone ash, and 3% EPK. For this tile. I did a few other tiles that had bone ash and EPK, however none of them were as successful as this tile. 

 

So at this point my plan is to make a lot of test glaze revolving around changing bone ash and lithium. I also might try adding small mounts of cobalt, and 6600. 

 

Lots of testing to come. Gotta go throw a ton of test tiles, and mix a ton of batches. Supposed to rain tomorrow, so it will be a good time to do it.

 

[glazenerd]

Joseph:

You have the one glaze ingredient that will make it all work- determination.

I question the bone ash only because you are adding yet another flux to already fluid glaze. The EPK will give you a glaze hardener, as well as some much needed alumina. The tile I had up contained 0.10 CoCarb, which deepened the dark color. I have no doubt that you will get it dialed in.

Nerd

 

Ray-- interesting recipe you shared.

[David Woodin]

I am firing one single cup. The worst yunomi I have made in a while and kept. So plain and ugly. But it will be a good glaze testing cup. Poured the inside with one pour and triple dipped the outside for thickness. I am firing to 2165 with a 50 minute hold, should put me to cone 6.5 then I am dropping 9999 til 1742 and holding for an hour. It will be interesting to see.

 

I didn't have time to modify my glaze I keep all my test batches in small 100 containers. My garage literally has over 100+ small containers of test glazes lol. I went and found my modified V's gold and I am firing it now. I will post results tomorrow afternoon. 

 

I hope yours comes out good. I would love to have a beautiful tenmoku.

 

I think Mountain Meg is laughing at us, she asked for a recipe and we are trying to find one for everyone! haha. lots of great information in this thread though.

I am curious about firing to 2165 F with a 50 min hold.  Even with this hold you will only get to about 2217 F which is less than cone 6 at a 108 F ramp.  I am missing something?

David

[Joseph Fireborn]

@David:

 

The first attachment is when I did a one hour hold. I went past cone 6. 

 

The second attachment is with a 50 minute hold.

 

These are orton self supporting cones. I don't know where you get that calculation from, but my heat work seems to be accurate with that schedule. I have a little kiln 2.7CUFT. Maybe that has something to do with it? I don't know much about this topic. I just test schedules with cones to make sure everything is right when I change schedules. 

 

I didn't post the cone 5 because it was completely flat melted. 

 

Maybe I slightly under fired. I dunno, looking at ortons examples of properly bent self supporting that second picture is about dead on, maybe a little less than what they have. Maybe I should go to 55 minutes.

[Tyler Miller]

David, it does the equivalent heat work of cone 6 without raising the temperature. Sometimes desirable for glazes with a narrower window between over and under-fired.

 

Joseph beat me to it, lol.  His answer's better.

[Joseph Fireborn]

@Tyler and David: I actually tested my glazes both way. A straight firing to cone 6, and a firing to cone 5 with that hold. The results of the firing to cone 5 with the hold produced much better glaze surfaces as well as better colors, more variety. So I decided to go with the cone 5 + hold firing schedule. Not all glazes are the same, but the ones I am using I had much better results with the 2nd schedule, thus that is what I am going with for now. My current schedule is as follows:

 

150F/h to 250F

 

400F/h to 1915F

 

120F/h to 2165F- 50 minute hold

 

150F/h to 2065F - 30 minute hold (drastically improves my surfaces of glossy gassy glazes.)

 

9999F/h to 1742F - 60 minute hold (brings out more variety from my glazes rich with iron.)

 

 

As far as the tenmoku goes, I have looked over my test tiles from the previous firing and my best results with the bone ash are where I lowered the amount of lithium to 3%. In fact now that I look at it. I have slight crystals where the glaze pooled that are red, not as big as when I have a heavy dose of lithium(which I don't want anyways) and bone ash. So I think this is the direction I will be going, and moving away from the lithium based tenmoku recipe I posted above. Also removing the lithium greatly increases my SiO2 to a much harder glaze surface, as this one is barely hitting 2.25 which is way below function use with that much lithium.

 

In the attached tile, near the middle and on the side you can start to see faint red crystals coming in through the glaze. The bottom of the right side of the tile has the colors that I want the most. Slight red crystals with a dark black drip of glaze.

[David Woodin]

@David:

 

The first attachment is when I did a one hour hold. I went past cone 6. 

 

The second attachment is with a 50 minute hold.

 

These are orton self supporting cones. I don't know where you get that calculation from, but my heat work seems to be accurate with that schedule. I have a little kiln 2.7CUFT. Maybe that has something to do with it? I don't know much about this topic. I just test schedules with cones to make sure everything is right when I change schedules. 

 

I didn't post the cone 5 because it was completely flat melted. 

 

Maybe I slightly under fired. I dunno, looking at ortons examples of properly bent self supporting that second picture is about dead on, maybe a little less than what they have. Maybe I should go to 55 minutes.

I am sorry,  I thought you were trying for 1/2 more than cone 6 when actually you wanted cone 6 @ 45deg So you are within 3 deg F of 45 deg.  the calculation comes from Orton Cone Calculation program.  I am glad you use the self standing cones.

David

[Joseph Fireborn]

David I probably mistyped something somewhere along to mislead u. I meant my first firing was somewhere around 6.5 because of those cones in that picture, this was with the hour hold. I get confused sometimes myself.

 

Edit: actually I see the confusion I did say cone 6.5. My mistake. I will edit that when I get on my computer later.

 

 

Orton cones are a lifesaver when trying new schedules and doing test things. Once I use them I pretty much trust my controller for a while then I will test again down the road to make sure.

[Crusty]

I live and die by Orton cones.. Manual kiln I have lol...

 

I like what you have so far, very interesting to see how small changes in the recipe affects the final outcome of the color... I am a huge Temmoku fan as well as Albany slip... i like to layer them together as well ,  get some interesting results.. Very feathery ...

 

Our plans as of now are to get a smaller kiln to test with and then get into making our own glazes... Our bigger kiln will be a bisque kiln or maybe convert it to gas... we just got a price hike from our electric company... UGH

[neilestrick]

Manual kiln I have lol...

 

Our plans as of now are to get a smaller kiln to test with and then get into making our own glazes... Our bigger kiln will be a bisque kiln or maybe convert it to gas... we just got a price hike from our electric company... UGH

 

If you run tests in a small kiln but fire work in a larger kiln, you will not get the same results. Little test kilns cool really fast. IF you plan to go that route, I highly recommend getting a digital controller on both kilns so you can do the same cooling cycle on both kilns. At the very least you'll want a digital controller to control the cooling on the small kiln to mimic the cooling cycle in the large kiln, even if you don't have a controller on the large one.

[Rex Johnson]

I realize the OP was asking about oxidation, but I f fire with gas and mix use this recipe in bith atmospheres just to see what happens, and it turns out nice either way.

It's a pretty forgiving and dependable recipe so far.

 

It's the Tem recipe available here as a PDF download.

"Making the switch from cone 10 to cone 6 ceramic glaze recipes"

 

Temmoku Glaze Cone 6, reduction
Whiting. 20
Custer Feldspar . 35
Kentucky Ball Clay (OM 4). 15
Flint. 30
Add: Red Iron Oxide. 10 %.

"A Cone 10 recipe that works equally well at
Cone 6; yields yellow “tea dust†crystals in
reduction. Not as interesting in oxidation;
just lies there and looks brown."

 

 

A single coat and then a Pete's Black in the dark areas. The Tem has a nice redness to it.

 

Tem inside with some treatment on the lip...

[Chantay]

Rex,

This might give similar results in electric with a three hour cool down after 1900F..

[Marcia Selsor]

I have lots of ^6 reduction recipes. I fired ^6 reduction for over 20 years while I was teaching in Montana and again in Tx.Here is my handout for a ^6 reduction workshop I taught in 2012 in Corpus Cristi

Some of these glazes have been used in Oxidation. Try the slow cool an holding.

 

Marcia

^6 Reduction workshop.pdf

^6 Reduction workshop.pdf

[Joseph Fireborn]

So for local reduction in a glaze, I was reading about all those copper reds using silicon carbide. I was thinking about tinkering with this for some tenmoku glazes in electric cone 6. Has anyone ever tried this? 

 

I read that you need to use a really fine silicon carbide. Do you guys think 325 mesh will be good enough to start? 

 

Edit: I was reading that 325 should be good enough if I screen it well. Looking forward to testing this out. I have always been curious to tinker with this and try to get a local reduction through chemistry. I love tenmoku so much and I can't stand not having it in my glaze options.

[Roberta12]

Joseph, I used the Selsor Tenmoku out of John Britt's book.  Added 5% Magnesium carb....it was pretty nice!

 

Roberta

[Joseph Fireborn]

Yea I have tried all of them in the book. The selsor is nice but it isn't want I am looking for. They are just too transparent for me under direct light. I want a dark black one like the picture I posted somewhere on this thread topic. Something dark with rust breaking. I have tried everything I know how to do over a bunch of test and I just can't get rid of the transparent at oxidation. So I am on to the next part. Local reduction.

[High Bridge Pottery]

Sounds like a good direction to explore. Digital fire seems to say its possible for iron but could have gas issues.

 

'SiC powder has some curious uses in ceramic glazes. It is employed to make crater and foam glazes. The silicon part takes up available oxygen to make SiO2 and the carbon combines with oxygen to make the CO2 that creates the blisters and bubbles. Using this mechanism it is possible to create reduction effects in oxidation firings, but with obvious challenges (blistering and bubbling). The carbon that silicon carbide particles release acts to reduce metallic oxides like iron and copper. Additions of tin oxide will aid color development, especially for copper reds. The Potters Dictionary has a good description of this.'

[synj00]

Grype! Great to see youre still at it! I had to take a break for personal reasons but I've picked up where I left off. I came to post the question "Does cooling have an affect on Tenmoku (Temmoku)?" and here I find some great information as you are already treading this territory.

 

Here is my testing its at cone 8 oxidation with quite a hold time. The leach 4/3/2/1 recipe and it works but its not anything like temmoku at all in oxidation even with a long ramp down in cooling. It looks cool but its not what I'm after. Its the journey not the destination right? :-)

 

[Joseph Fireborn]

Sebastian! Good to see your still at it. I tried all types of cooling if you go back through this discussion. I got some really neat effects and I have tried more since then and had more success, but still not what I am looking for. I really love the black that comes from the reduction tenmoku, I am sure its going to be hard as crap and a lot of testing, but I enjoy that part. 

 

That glaze is really nice where it pools at the bottom. I have had that same effect on almost all my attempts at oxidation tenmokus. The places where the glaze pools is always so beautiful and dark, but the rest is too transparent for my taste.

 

@Joel: I have no idea what will happen, I am sure the first attempts are going to be a disaster! But I will keep working on it. Now I just have to find a place to start looking for cone 6 reduction tenmoku's that I can start applying the carbide too!

 

One of the things I am excited about is I do indeed get a good tenmoku from this effect, what else could i do? maybe a beautiful shino? I dunno. I just feel like this area offers a lot to be explored! 

[High Bridge Pottery]

It certainly says bubbles will be an issue and it can result in long firing times and lower alumina glazes to try and let the bubbles through the glaze. I think the problem is it does nothing till the glaze is molten and starts attacking the silicon carbide so all the gas has to escape through molten glass, which pointed in the right directions gives the crazy craters.

Is it sold at pottery supplies?

[Joseph Fireborn]

I just bought a pound of 325mesh at uspigment. It was only $4.75 or something. I am not sure if 325mesh will be good enough, but if it isn't I will have to start searching for suppliers for a finer mesh. On the articles for copper reds they are using 800 mesh, so this could fail horribly, but for $4.75 it wont cost much to find out.

 

I am super excited to test it all out. I am going to make like 100 test tiles tomorrow and start drying them under a fan, then I plan on finding 10 or so recipes for cone 6 tenmoku reduction. Mixing up 3 batches of each, so 30 in total, then putting in different amounts of carbide in the 1-3 batches and testing to see what happens. 

 

Hopefully I can get a good result? 

[High Bridge Pottery]

My preference for any glaze test is now currie tile method. There is no quicker way to crack out 35 different test tiles, I can go start to finish in under an hour. Well when I had the studio  damn.

[Joseph Fireborn]

My preference for any glaze test is now currie tile method. There is no quicker way to crack out 35 different test tiles, I can go start to finish in under an hour. Well when I had the studio  damn.

 

I really need to learn how to do this. It would save me a ton of headache probably. I am gearing up to do a lot of work this summer. I have had so many health issues in the past, but I have slowly been taking care of them. I am probably in the best health that I have been in the last 10 years. 

 

My plan is to use my current glazes to get my etsy shop populated with tons of items, and test for other glazes while I fire those for sell. I guess I should figure out this currie stuff cause mixing 30 batches of 100g's is a waste and takes a lot of time. You should do a video on youtube explaining your process and how to set it up!!!     

[High Bridge Pottery]

I did record a little bit of footage once of testing but that never made it anywhere, I do have a few tests that I need to run so I will keep it in mind and try to make somekind of tutorial for you to watch right now I am a little confused being out the studio with how pottery fits into my life but I will slowly find its place.