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Member Since 18 Dec 2015
Offline Last Active Today, 07:25 PM

#127089 Qotw: What Movie Best Describes Your Adventures In Clay: And Why?

Posted by glazenerd on Today, 06:39 PM

Terri" there are two classic scenes in Blazing Saddles: if you are thinking of either>>>. I'm telling!!!


When I first started in clay:  "Field of Dreams".... I was full of hope and possibilities.


After a few years it was: Forest Gump... seems like I kept fumbling through until I found success.


The last two years: " A Beautiful Mind".. I wake up in the wee hours with clay talking to me..... someone book me on Dr. Phil please!



#127042 Filling The Kiln With Tiles

Posted by glazenerd on Today, 07:03 AM

Inversion temperature is when the first phase change of silica ( flint) occurs: alpha quartz changes to beta quartz. An extensive vibration of molecules at an accelerated rate, which can crack larger pieces if this phase change occurs too quickly. Matthew v started a thread called " inversion temperature". Do a forum search, you will find the info.
The largest flat work I have done is 24" x 24" x 3/4" thick. ( counter top slabs).
I work with porcelain almost exclusively. I do however blend in 15percent of molochite to kill plasticity.
I used straight alumina hydrate under them, so they would move during the firing. Yes, drag (friction) can also split them.

The other possible issue could be how you use your slab roller. You have to make smaller compressions as you, as well as roll in both direction instead of just one. On large pieces, I roll way past the width and length I need, and cut my piece out of the center. The ends and sides are the weakest, so I avoid cutting tiles on the edge of the slab.

I have pictures in my gallery, but I am on my wife,s I- pad, and have no idea how to use it to post pictures.


#127025 Filling The Kiln With Tiles

Posted by glazenerd on Yesterday, 06:22 PM

I do not think your problem is with stacking,or drying, or with forming technique. I think your problem lies in your firing schedule; I think you are blowing through the inversion temp too fast. On the edges of the tile in direct contact with the shelf, I would expect to see small stress cracks.

From 1000f to 1100f, you should not ramp any faster than 100f (60c) an hour. I fire tiles up to 24 x 28 inches.
Inversion temperature is 573 celesius.

#126958 How Clay Has Shaped You?

Posted by glazenerd on 20 May 2017 - 06:35 AM

After reading these two posts: perhaps I will just stick with experimentation and research. After 44 years of construction, all I really want to lift is my 44 oz. coffee mug.

#126907 Will Lowering Specific Gravity Always Make A Glaze Less Likely To Run?

Posted by glazenerd on 18 May 2017 - 04:56 PM

Recently we changed bentonites "

The beginning of your post is the answer to your question. Most bentonite sold in the pottery trade is sodium based. Sodium bentonite has a high cation exchange rate: it becomes gelatinous quickly/ instantly. So what seemed thicker to you with less water was actually electrophoresis. Fancy word for " man that stuff got thick quick!" After stirring awhile and some timed passed: not so thick no more. My guess you have purchased calcium bentonite, which has a much lower cation exchange rate. Now it seems it requires more water to hit the same viscosity. Calcium bentonite clay (smectites actually) will hold more water in its particles without becoming gelatinous. So what you perceive as a change in viscosity is actually a change in chemistry.
Calcium bentonite is a much more stable product than its cousin,just make the adjustments in water and go from there. You will also find calcium bentonite a much better suspension agent.

#126748 Qotw: What Do You Listen To While Working In The Studio? Music, Tv, Talk Radi...

Posted by glazenerd on 15 May 2017 - 10:55 PM

Ms. Bea


Hi Bea...... having lunch with me on the deck.. She is chewing by the way, not snarling.



#126668 How Clay Has Shaped You?

Posted by glazenerd on 13 May 2017 - 11:11 PM

How has clay shaped my life?  Hmmm.. I was thinking more in the terms of "ruined my life." I had a life, was happy, content, and went fishing often. That was until I saw a crystalline vase in Williamsburg, Va. back in 2007. I spent over a year doing online searches trying to figure out what I had seen. After I figured that out, I spent a few months researching it until I dropped a rather tidy sum buying kilns, rollers, chemicals, and the other necessary sundries required to make crystals.


I went from never working with clay to firing crystals on porcelain clay. I learned to make my own glazes, and have never bothered with premixes. In 2012 or so I began to realize through extensive experimentation, that the clay was effecting crystal growth. So I began researching clay formulation, only to realize there was no such thing as clay formulation.  Hey- that was fun. So I spent several years reading research documents on any and all aspects of soil sciences and elemental studies. In 2015, I had the pleasure to met and study with Ron Roy at the NCECA conference in KC. I have spent the last two years working on formula limits for porcelain and stoneware clay bodies. I am currently writing a book on clay formulation, which I fully expect to sell ten copies.


I prefer to look at it as: shaping the future of clay. My only other option is to accept the fact that I have become overly obsessive about clay.



#126667 Gray Areas In Fired Glazes

Posted by glazenerd on 13 May 2017 - 10:53 PM



Brown / dark stoneware bodies have high levels of iron / titanium / and magnesium. It is also common to find large particles of feldspar minerals: along with high levels of carbons (primarily sulfur from lignite coal). The very same elements that make these bodies all warm and toasty; are the very same things that cause problems.


MGO test2
In testing magnesium levels in clay, you can see the grey cast in bar #3 and titanium in bar 5. High levels of these elements can certainly leach into a glaze causing discoloration/s. Magnesium levels are the more probable cause as seen here:
Mgo Test 2


There can be other reasons, but if you are using a dirty/dark stoneware body; then Mgo is the most likely culprit.



#126574 Alumina Hydrate, Alumina Reactive & Aluminium Hydroxide

Posted by glazenerd on 12 May 2017 - 07:20 AM

You have been mixing glazes for less than a month, and you are asking chemistry questions? Going down the glaze rabbit hole already: be advised it is a very deep hole.
Hydrate- contains a form of water
Reactive- reactions, typically used to cause a chemical reaction, usually a testing regent.
Hydroxide- potent stuff, all hydroxides are. Oxygen and hydrogen molecules are bond together, which creates strong reactions when broken. I have some lithium hydroxide out there, it will melt the clay body if used in high percentages- highly caustic, 12.95 ph.

Potters do not pay much attention to ph, but it plays a major role in clay and glaze chemistry. We almost always deal with alkalinity, all fluxes are alkali. Plasticity in part is based on ph. Soluble salts ( pearl ash) runs up to 13.95, while most fluxes except lithium run between 8.5 up to 9.2. The higher the ph, the faster something melts. Years ago I bought a ph meter, and mix my crystalline glaze to a ph level in lieu of percentage. Pieces in the colder part of the kiln are slightly higher and pieces in the hot area, slightly lower.

See what happens when you go down the glaze rabbit hole? You make posts in forums that makes everyone reading go huh?


#126507 How Clay Has Shaped You?

Posted by glazenerd on 11 May 2017 - 06:28 AM

Glad to see someone from the next generation that will carry the torch forward.


#126506 Qotw: The Psychological Ups And Downs With Clay

Posted by glazenerd on 11 May 2017 - 06:26 AM

Woke up this morning with a qotw in my head

What movie best describes your adventures in clay: and why?


#126414 Qotw: The Psychological Ups And Downs With Clay

Posted by glazenerd on 08 May 2017 - 10:19 PM

I have a truck load of tenacity and endurance: I can and have gone for years with little to no successes. I know it takes times, and very long hours to figure out how the chemistry works in specific terms. If I wanted to know in general terms, I would just buy some books. However, my personality requires me to know in exact terms.  After nearly a decade, I know.



#126413 Nine Warning Signs Of An Amateur Artist

Posted by glazenerd on 08 May 2017 - 10:15 PM


Not everything that has value has to be a monetarialy profitable pursuit.

Glad to hear that, spend much of my time researching and studying clay and glaze properties. I find my joy in discovering how it works, rather than making if work for me.



#126348 Clear Glaze Chemistry

Posted by glazenerd on 07 May 2017 - 09:03 PM

After rereading my post, I get your reply.

Let me rephrase: give us a list of other available materials that you have access to. Perhaps something else will be useable.


#126325 Nine Warning Signs Of An Amateur Artist

Posted by glazenerd on 07 May 2017 - 02:57 PM

Art evokes an emotional response. Given the responses, this article therefore should be viewed as such. Passion is a key part of any artist; so the reactions to this piece should have been expected. Even the goal of educating emerging ceramicists has been met, now they realize there is no one set path to achieve success in this industry. Pottery can be a business, it can be art, and it can be hobby. Being an old farm boy, my view point tends to be more simplistic: you will reap what you sow.