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glazenerd

Porcelain Survey

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Well I was a recipient of Tom's porcelain testing. I have been throwing it and balling it up for many weeks now to keep testing forms. I have fired a few pieces and the glaze was pretty much as expected for a porcelain single fired. The pot's were nice and glossy and the colors were bright and beautiful. 

 

Throwing properties:

 

1. It was soft. I thought it was going to be too soft until I actually threw it. It held together just fine as good as any commercial porcelain I have thrown that was much stiffer in the bag. This was nice because it was so much less effort to throw and still resulted in the same ability to make odd shapes with shoulders and thin walls.

 

2. I noticed that when I wedged the clay back up and did a crappy job I would have air bubbles while throwing. However the bubbles popped as I was throwing. You can literally hear the bubbles popping between your fingers... Never had that happen before as I was throwing, usually had to take a rib to the pot to rid myself of a bad wedge job when I was in a rush.

 

3. I throw pretty dry already anyways. I use the slip on my hands and not much else, so I can't comment on how it would work if I added a lot of water. I add water to center and open, then never use anymore water. So I had no issues with over saturation. 

 

--

Drying properties:

 

1. Tom told me to not cut the pot off the bat. I was pretty skeptical at this. I tried it. The pot was a little past leather hard when it released but it was still plenty trimmable. I guess this could be different depending on everyones studio though. I have a drafty garage studio. So my pots dry pretty fast when left out. I can throw in the morning and trim in the evening. 

 

2. No cracks at all, no matter how fast I let it dry. 

 

--

Glazing properties don't really have much to say besides the glazes looked beautiful and surface was high quality. 

 

Just wanted to report this back to nerd and for others to compare if they got a sample. Maybe we have different opinions. I liked the clay. I don't use white bodies for most of my work so I have no practice use for it, but if I threw white clay I would probably try to use this clay. I loved how thin I could throw it and not have to be so gentle.

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Joseph:

 

Thank you for the feedback. Sounds like the only adjustment I need to make is lower water content by 3% or so. I am using an old loaner pugmill that is on its last legs: it cannot handle much back pressure from stiffer mixes. However, I will have new equipment coming up this way shortly: first of August or so. Think maybe I need to remove an additive all together, meant to increase drying time: but sounds like it is holding water in the clay. Will have to test that. Very interested in seeing how the redstone body turns out.

 

Nerd

 

** I have made one final change to the formula since everyone has received samples: it is slightly firmer, with even more durability on the wheel.  

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Douglas:
I have been reading up on wood/ salt firings. Marcia Selsor is getting ready to torture my porcelain in raku and a wood fire I think? Not sure how much it would flash, it is a very low sodium body. At some point in the future, I will be making specialty versions for those uses.
Nerd

*** the Redstone body will do some interesting things in a salt/ wood firing. I am picking up some clay from a brick factory in Missouri next week, that has nearly 8% iron content! with high titanium as well. My cousin sent me a few pounds to play with. It turns reddish brown at cone 6, and purplish red at cone 10. They do not sell it on the market, I have to take five gallon buckets down there and fill them by hand. It is some pretty cool stuff to play with. It has a lot of tooth: 20-80 mesh particles. You get some natural speckling just from the clay.

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*** the Redstone body will do some interesting things in a salt/ wood firing. I am picking up some clay from a brick factory in Missouri next week, that has nearly 8% iron content! with high titanium as well. My cousin sent me a few pounds to play with. It turns reddish brown at cone 6, and purplish red at cone 10. They do not sell it on the market, I have to take five gallon buckets down there and fill them by hand. It is some pretty cool stuff to play with. It has a lot of tooth: 20-80 mesh particles. You get some natural speckling just from the clay.

 

NOM NOM NOM. ME WANT.

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Stoneware?

 

C6 Almond Porcelain

 

Pure porcelain with colorants to produce a stoneware looking body.

RON: This is a crystalline glaze with no seeding agent. Typical crystalline glazes run around 8. + COE, on my porcelain at 6.78 COE. There are no visible crazing lines, even though the test kiln drops from 1950F to 200F in about four hours.

 

After inking the piece, cording lines did appear that were not visible before.

 

Ink 2

 

Now to investigate the reasons why they did not break through to the surface.

Note: COE was amended to reflect HiExp. Body: 6.12 is standard Nerd porcelain.

Nerd

 

Pictures, comments, and responses after this post were moved to the COE Study thread, under Clay and Glaze Chemistry section. Forum guidelines also request that content stay on subject. The topic is porcelain clay, not crazing issues.

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Stoneware?

 

 

 

Pure porcelain with colorants to produce a stoneware looking body.

RON: This is a crystalline glaze with no seeding agent. Typical crystalline glazes run around 8. + COE, on my porcelain at 6.12 COE. There are no visible crazing lines, even though the test kiln drops from 1950F to 200F in about four hours.

 

Nerd

If its not crazing, what I am seeing in the glaze when I zoom in on the photo?  

 

-SD

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Stoneware?

 

 

 

Pure porcelain with colorants to produce a stoneware looking body.

RON: This is a crystalline glaze with no seeding agent. Typical crystalline glazes run around 8. + COE, on my porcelain at 6.12 COE. There are no visible crazing lines, even though the test kiln drops from 1950F to 200F in about four hours.

 

Nerd

If its not crazing, what I am seeing in the glaze when I zoom in on the photo?  

 

-SD

 

Yup, I'm seeing it too when viewing in the gallery as large image.

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You are seeing micro crystals: very common for crystalline glaze.  I looked at it under my microscope before I made the claim of no crazing.  Anything else?

 

Nerd

 

 

Interesting. So from your image on post 83 the aqua glaze doing this is crystals?

post-747-0-19132500-1500779006_thumb.png

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Nerd,

 

I've been following this thread since I posted my question on July 22 asking what was I seeing in your photo if it wasn't crazing.  It now appears that the discussion has been edited.  Specifically,

 

  1. You original post dated 7/22 (post 83) now contains an additional photo of an "inked pot" with the following new content  After inking the piece, crazing cracks did appear that were not visible before...Now to investigate the reasons why they did not break through to the surface. (italics added for emphasis)
  2. All of your posts in response (e.g., explanations of micro crystals, threading, felting, higher titanium level in the clay body, etc. ) to me, Min, RonSa, Neil and Mea were deleted except to the extent that these responses survive when they were quoted by other forum members).

I'm assuming good intent on your part to try and "clean up the record".  However, I think the undocumented way in which it was done creates confusion for future readers and distorts the substance and content of the thread.   First and foremost, the additional information substantively modifies the content and context of the original post. Now it appears that the series of questions and comments posed by me, Min, RonSa, Neil and Mea are off base.  In fact, new readers of this thread would likely think that we misinterpreted your 7/22 post, and might even conclude that we were unfair in our comments.  Certainly, they would not get the sense of the healthy discourse and process that opened up a new path of investigation for you.

 

Secondly, the learning and thought processes contained in the now deleted responses have been lost, I learned something about micro crystals, got to see some cool stuff happening in the glaze and contemplate possible alternative explanations to what I was seeing.  Now all of that is gone.

 

Going forward, I think all forum members should be mindful to use "best practices" when their edits impact the content, flow and logic of a thread. It's one thing to correct a spelling error, close an open thought or change a dangling participle without documenting it.  However, if members are going back in time and supplementing older posts with new information (especially if it impacts the subsequent conversation), it needs to be changed in a transparent manner with good supporting details of what was changed and why. Likewise, when deleting information that impacts subsequent conversation, we should use a strike through and/or provide an explanation of what and why it was struck.  

 

 

-SD

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With all due respect this is very selective re-writing of the conversation, not editing for clarification. What's the point of having an intelligent discourse if it's only to be deleted if the conclusion isn't satisfactory? In the grand scheme of things this is all rather silly, it doesn't matter a toss if the glaze crazed or not, it can be fixed to be craze free if necessary.

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Ron:

Final results with the colored porcelain inlay work.

C^ porcelain, colored porcelain banding

 

I like the banding/inlay idea, just need someone with better artistic skills than me to make something with it.

 

100 0717

 

Almond porcelain with colored porcelain inlay. Clear glaze. Color is from the clay. Once fired.

 

Nerd

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New cone 11 porcelain body:

 

I test fired my experimental cone 11 porcelain body:

C11 cone

 

I only had a cone 10 cone: from looking at the melt I hit cone 11?  Never fired this high, will let others who have judge that result.

 

C11 Porc.

 
Crystalline glaze, but I only did a ramp hold for 30 minutes. Just wanted to see how the body would hold up to the high fire.  Peak temp 2345F, held for 30 minutes.
 
For those who have the cone 11 samples for wood-firing- go ahead and light it up.
 
DW.. notice anything unusual about the catcher?
 
Nerd

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For those who have been following, here are the most recent porcelain tests. All four have the exact same crystalline glaze, mixed and applied from the same batch. 3% copper carb. And 0.10% cobalt carb. The four porcelain bodies have various levels of oxides and opacifiers: creating the different glaze reactions:post-73441-0-73784100-1502313348_thumb.jpgpost-73441-0-19230100-1502313363_thumb.jpg

 

Nerd

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