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#3228 Amaco Ancient Jasper Question

Posted by Steve Lampron on 22 October 2010 - 03:17 PM

ANCIENT JASPER: Hello all and stay with me as I am and old guy and not blog capable. I am the VP of Technical Services here at AMACO and the engineer that developed this glaze. I am very sad to hear that some of you are having difficulty with this glaze. It is actually a very easy glaze to work with and will yield excellant results. Let me give you a few tips on this type of glaze in general an then some specifics about ANCIENT JASPER.
Many midrange and high fire glazes used by ceramic artists are what I call FLOAT glazes. These are the pretty glazes that tend to seperate out different colors in areas where the glazes are thicker. ANCIENT JASPER is this type of glaze and what it floating out is iron oxide. Iron is one of the more interesting colorants simply because it can be in so many different oxidation states. This simply means that it can make a ton of different colors. With any float glaze, enough thickness of glaze must be applied in order for the excess iron to float to the surface. If the glaze is thinly applied, the glaze will tend to be drier and a very unpleasant color.
This glaze was not developed where any massive amount of glaze needs to be applied. If it had needed this I would have told everyone on the label. We actually never had any issues getting red at all. I always try new glazes on all of our clay bodies to make sure there isn't some issue I need to know of. We also fire them at cone 5 and cone 6 to check stability. We found no issues with this glaze on either account. By now you probably saying, great but it didn't work for me. I will list some good parameters below for you to follow and I am 100% sure you will find this glaze simple to use and that it will yield great results.
1. Temperature: The red color is actually the first color to float and the use of more heat will tend to make it turn to the purples, yellows, browns and black. This means you will tend to see slightly (and I do mean slightly) more red at cone 5 than cone 6. No soak is needed for this glaze and actually soaking it will cause more red to fade into the other colors.
2. Thickness: The glaze must be applied with enough thickness to float the iron.
3. Kiln cycle: I fire all the glazes we develop in an electric kiln at fast, medium and slow speeds. Red color will be developed at all speeds but the faster the firing ~6 hours (tons of red) the better the results. I always quality check each batch at cone 5 in 8 hours. 10-12 hour cycles will cause more red to fade to the other colors. This is most critical within 200 defrees of peak. If your elements are weak and it takes the kiln a long time to achieve the last 200 degrees, you will find less red.
4. Cool down: No special cool down is needed nor will it help develop any red color. Letting the kiln simply shut off and cool naturally is all that is needed.
4. Clay Body: I have tested this on porcelain, typical stoneware bodies, bodies with grog, bodies without grog, brown colored bodies, etc. I develop red on all of them. I have found that when using our #1 Porcelain slip that the color transition away from the red tones is very pronounced (although it makes a rainbow of the other colors). This is because for a cone 5 porcelain slip alot of soft flux is needed to tighten the body. The flux in the body mixes with the glaze and actually makes the glaze softer (simulating more heat).
5. Texture: This glaze loves texture and will make some incredible colors. The texture makes the glaze get thinner and thicker in areas. The thicker the glaze the easier it is for it to stay red. The thinner the glaze gets the hotter that area of glaze gets and it shifts to the other colors.

These simple tips should help everybody that wants to make ANCIENT JASPER work. I suggest running a few tests of glaze thickness in your next kiln load and follow the firing rules above. Three nice coats on any typical stoneware body, fired to cone 5 or 6 in 6-8 hours with no soak and no special cooling curve will yield pieces just like the ones we showed in the ads. These were just pots we made in the lab. Honestly I have never actually made a pot that didn't make colors just like those pieces.
I will attempt to post a few more photos here today and next week we will post a board I made with all of our clay bodies fired at slow, medium and fast so you can see the slight differences.
Let me know if this helps.
The photo files are too big to upload. I will have someone help me make them smaller for next week.

#56617 The Dangers Of Advice Without Experience

Posted by ChenowethArts on 14 April 2014 - 03:03 PM

There is an African proverb that applies to taking/giving advice: "Never test the depth of a river with both feet."

#18863 Was: Etsy or Ebay? Now: When Should You Start Trying to Sell?

Posted by metal and mud on 02 July 2012 - 01:55 PM

I've been thinking about this thread a lot this weekend. I've been having a wonderful time making gift items out of clay--2 and 3 inch lidded boxes on feet, textured and glazed in pretty colors, little Indian rugs hanging from metal racks that my son makes, plates carved with our local Organ Mountains and a moon and glazed to look like moonlight--etc.--different things that just come to me. I had so much fun making them that I couldn't NOT do anything with them. I also know that I need to do a work many times to get better at it; already the lids on my clay boxes fix much better. I am a small business owner and it only seemed natural to sell my items, so last December I got "certified" as a vendor at our Farmer's and Crafts Market. I get such a kick when someone buys one of my--admittedly--imperfect items. They make them happy and me even happier. I use my revenue to buy supplies, thereby supporting my hobby. It's disturbing to me that someone should suggest that we shouldn't put our items in public until many years have passed, implying that the works shouldn't be in public until much better in quality and near-perfect. I view my craft as an incredible relaxation whose result brings happiness to both the maker and the purchaser. After reading some of the posts I started to doubt myself in my decision to put my works in public and my ego on the line, but I had a good firing over the weekend and I know that on July 4th, my next market, some local folks will get a kick out of my little items and I won't stop bringing them to market, for one, nor trying to make them better and better each time. I hope I never achieve perfection because then I might stop.

#54842 Video "a Love Story In Clay"

Posted by Isculpt on 17 March 2014 - 03:28 AM

My husband Bill and I are very private, low-profile people, but when Piedmont Crafts Guild, the oldest crafts guild in NC, asked us to participate in a series of short videos about guild members, we couldn't say 'no' to a guild that has done so much for so many.  Consequently, we spent a day last summer with a mini film crew at our rural South Carolina home near the Catawba Indian Nation, whose thousands of years of pottery tradition my husband carries on.  In contrast, as some of you know from the outpouring of help that I've received from this forum, I am a self-taught sculptor.  What I really like about the video is how it shows that, like everyone who chooses to work in clay, our love for the medium enriches and defines our life.  (What I don't love, having just seen the film, is that it now occurs to me that taking a few minutes to apply cosmetics (on me, not Bill) might have been a good investment of my time before the crew arrived to make a high def video!  :huh:)  Oh well.... 




Added note:


Thanks, all of you for your kind words and warm response to the video.  I have to say that the decision to focus the video on our relationship along with our work was the choice of the makers, and it struck us as slightly ironic.  After the intensity and intimacy of a shared life in craft, we were adjusting to a new reality that took Bill away from home and studio for all but a few hours a day.  After 25 years of working side by side, our new reality is that his days as Chief of the Catawba Indian Nation are filled with administrative duties for a tribe of 3,000, lobbying Congress on Native issues, and handling intense political pressure as he works to regain some of the sovereign rights lost to his tribe. Meanwhile I keep the homefires burning and look forward to the day when his crucial work on behalf of his tribe is done and I regain my studio partner.


The video shows us working on several pieces that are pictured in their completed states below.

B Harris small image.jpg Bill Harris Pottery_054 small image.jpg BLUEBIRDS SWIRLED AROUND HER clay sculpture by Jayne Harris.jpg JAYNE HARRIS SCULPTURE 46 SMALL IMAGE.jpg

#46175 12 Inch Club

Posted by neilestrick on 19 November 2013 - 10:03 PM

Membership has it's rewards.....I'm not sure what they are, but I'm sure they'll be awesome.


#37769 What do you collect and why? | June 19, 2013

Posted by trina on 26 June 2013 - 07:18 AM

oh man and i was so clinging to that one positive rating point.....T

#56596 How Are You Managing Your Web Resources?

Posted by Chris Campbell on 14 April 2014 - 08:11 AM

Here is a facebook posting of an image that was presented during the "Using Social Media" session. It explains in simple terms what every site is for.


As I commented on facebook, there is NOTHING here about "Look at the sales I made and the money I received from using all these social media sites."


With me, the jury is still out on the usefulness of spending valuable studio time in the short attention span theater.

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#55814 An Apology

Posted by Tyler Miller on 30 March 2014 - 10:22 PM

I suppose I should come forward and say that I was the one who asked TJR to apologize.  I'm very impressed with his humble and cordial response.  TJR's a good guy and a great potter. I wish my teapots looked as good as his.  He's also Canadian, a fine quality in anyone ;).


My feelings about not pointing out spelling and grammar mistakes come from my experience with languages.  I was a classics student for a long time and I'm still an all-around word-nerd.  I know my rules well, but after a time, you learn that spelling and grammar are very artificial constructs that have no bearing on artistry, intelligence or the ability to communicate. They are merely indicators of your schooling and skill with words.  Shakespeare had a vocabulary of well over 20K words, and invented a significant portion of our modern lexicon.  He also is known to have spelled his name five different ways in his own lifetime.  His own name!


Not too long ago, a gentleman posted on The Bladesmith's forum inquiring about making a knife for his son with only his limited hand tools.  Literally every word was spelled wrong and he used no capitals or punctuation.  He likely had the legal minimum of education for his state.  But he wanted to learn now.  People jumped on him, but the truth was he was perfectly legible, if you bothered to say what he wrote out loud.  He didn't need punctuation, he had a built in cadence to provide sense to his words.  He was writing in poetry, not prose, poetry.  To understand him you needed to read his rhythm and cadence.  After everyone had jumped on him, he never posted again.  eye wud hav reely lykt to no how his nyf ternd owt  eyem sher it wuz grate Very rarely does poor spelling and grammar amount to nonsense.


Then there's the fact that a lot of people have dyslexia and struggle with spelling pathologically--not to mention all the other learning disorders out there.  I once knew a perfectly brilliant man who was rendered illiterate because of Reye's syndrome in his childhood.  He was physiologically incapable of reading.  He had very real cognitive problems because of his illness, but he was an excellent carpenter, machinist and labourer.  At 45 he's finally learning to write his numbers with great difficulty--he could read them, but writing them used a part of his brain that he struggled to muster.  He was very proud that he painted his house number on his mailbox.  You don't need to read to make a pot and some of the most brilliant artists I know aren't the greatest with words.  Ann Rice, author of Interview with a Vampire etc.  is dyslexic and held off writing because of it.


That said, I'm all for orthography. It's necessary for science and modern communications.   To the argument that precise spelling makes search engines easier, I recommend using  Google with "site:http://community.ceramicartsdaily.org/" and entering your search terms after that.  No offence to the mods/admins, but the IP boards search engine is difficult to use at the best of times, and you need to be actively trying to misspell words to miss a term with Google.


I'm also not so sure language degradation is a bad thing.  Bad Latin eventually turned into La Commodia Divina, Don Quixote, Les Miserables, etc.  English is past due for a change, IMHO.


I guess my point with all this is to maybe ask everyone to think about where their preoccupations with spelling and grammar come from, and what they really mean.  My own feeling is that unless you're a teacher in a classroom teaching students, or you're helping someone achieve some sort of goal (resume, essay, publication, etc.), or you feel you're helping someone, it's unfounded.  I can think of at least three teachers I've known (one a neighbour, one a professor for whom I worked, and one who taught me) who used pointing out spelling and grammar mistakes as a way to cover up their own insecurities.  Google the phrase "sine nobilitate," and read about what holding someone to an arbitrary standard can do.


I hope none of this offends anyone or comes across as accusatory.  These are simply my feelings on the subject.

#55314 Why Decorate Pots?

Posted by TJR on 24 March 2014 - 02:52 PM

I am actually in a group of artists called the GAWMYS. Good art won't match your sofa. We have a group show coming up in 2015. All of us are art teachers or retired art teachers. None of us make work to match furniture.


#55263 What Has Been Your Worst Re Encounter Of A Piece Of Your Pottery?

Posted by Marcia Selsor on 23 March 2014 - 11:23 PM

OK this is at the same time the funniest and embarrassing reencounter of an old piece. It defines the need for the hammer but also can keep us humble and shows we all start from somewhere..
selsorcarbondatedsmall.jpg This was posted above the sink in my classroom by a student who cam across one of my very first teapots in california in possession of an old classmate from 1967.The pot was made in Philadelphia as a sophomore in college. I kept this posted above the sink for years. I think it is one of my most cherished possessions.I had to wait til I was home because it is one my larger laptop.
I added a slightly closer view. I hope you can read the writing. My students had a good sense of humor.


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#52707 You Know You're A Real Potter When....

Posted by bciskepottery on 16 February 2014 - 10:58 AM

When you wedge one-handed . . . follow the link to June Perry's blog and watch the video posted Brett Kern. If you see yourself in the video, you're a real potter.


#52514 You Know You're A Real Potter When....

Posted by Wyndham on 14 February 2014 - 10:25 AM

When you're so disgusted by a glaze test that turned out so totally off that you smash it in the shard pile, THEN.......

six months later while walking to the kiln you see this GREAT shard on the ground. You race back to your notes only to discover that page is missing.

You put that shard on a shelf to remind you to let the glaze live long enough to talk to you.


To err is human but to lose a great glaze is unforgivable.


#49945 Opening

Posted by neilestrick on 11 January 2014 - 01:45 PM

The problem (one of many) with the strong arm tool is that it doesn't center the clay well at all. It may well get it spinning in the middle of the wheel without wobbles, but that is not centering. Centering is a state of being for the clay, not just a position on the wheel. For clay to be truly centered, it must be well mixed and uniform, which is accomplished through coning the clay up and down. Without the coning process, the clay will go out of center when you open it, because the clay is uneven inside, which you can see happening when he opens the 'centered' ball. It will just get worse as you try to pull up the walls. While these types of tools may work for people who have certain physical limitations with traditional methods, they are poor substitute for practice and will limit the growth of your throwing skills.

#45898 What Do You Like Making Vs. What Sells

Posted by neilestrick on 16 November 2013 - 04:05 PM

If people see an obvious use for something, it tends to sell well.



Bingo! Even with something as simple as a bowl, which has a million uses, people seem to need to be told what it's for. I can't count how many times someone has come into m y booth and said 'That's a beautiful bowl, but I just don't know what I'd use it for.' Food, maybe?!? Of course, as soon as you say 'ice cream bowl', they say 'I don't like ice cream'! How about salsa? 'I thought you said it was for ice cream'. AAAAAUUUUUUGH!

#44874 Why New Blisters On Re-Fired Glazed Pot?

Posted by JBaymore on 30 October 2013 - 10:14 AM

This is almost for sure a body outgassing issue.  Likely caused by the BISQUE firing from a lack of enough oxygen present for enough time, not from the glaze firing.   The cumulative heatwork from the second glaze firing just allowed the more melted pyroplastic clay body to show what was hiding inside the body to start with. 


You likely can't fix it at the glaze firing point.


Many "glaze firing defects" come from the bisque firing, not from the glaze firing.  They only SHOW UP in the glaze firing.


Tightly stacked bisques, particularly fired in electric kilns, often have the issue of two things that combine to cause issues in the GLAZE firing.  On is poor oxygen flow and dispersion in the load.  The other is the thermal lag of the load.  Put em' together.... and whammy.


There are numerous reactions that have to happen to the clay body in the bisque firing.  Some require oxygen to be present (inside the clay body walls).  Others just need to have enough time for evolving gases to migrate out thru the clay body.  Some just need to have herat energy applied.   All have a specific temperature or temperature range at which these reactions happen.


Cones are usually out in an "exposed area" (in the open) where you can easily see them.  Thermocouple probes for controllers are also.  These devices are measureing the heatwork and temperature in a location very different from the interior of the walls of a piece of ware, particularly if the loading of stacked up wares is densely packed.  Therfore, sometimes the work is not fired to the heatwork that you THINK it is, no matter what you cones or controller are telling you.  This issue is called "thermal lag".  That's the amount the load is "lagging" behind the indicated temperature on a measuring device.  There is ALWAYS some thermal lag.


Then there is the penetration of oxygen into the load.  The edges of a stacking get this O2 pretty well.  The interior of a dense load does not.  If the kiln does not have good air circulation from an active draft of some sort, this issue gets worse.  Electric kilns without local pickup vents are very difficult to get "right" with a dense load.  Local pickup vents improperly installed or too small for the kiln unit are also causing issues with inadequate airflow.


If you tend to nest bowls one inside the other in large stackings in an attempt to have an efficient use of space... this can make this issue worse, affecting both oxygen penetration and thermal lag. It can also impede necessary outgassing.


This stuff is an IMPORTANT understanding to mastering firing operations.  A main point from my ceramic materials and also kiln design and operation courses....... There is no such thing as a cookbook firing schedule.  Firing is specific to the particular material being fired, the particular kiln being used, and the specific stacking job.  You need to know when you have to alter thngs to get optimum results.


SOMETIMES, you can fix the poor bisque by dragging out the lower (bisque range) part of the GLAZE firing.  Effectively you are doing what you should have done in the first place.  Glaze firings are almost always stacked more openly....so heat penetration into the load and air circulation is better.   However if you have a glaze application on the pieces that tends to become gas impermeable (particularly to O2) at a low temeperature (like American soda based shinos in highfire), then this can block the gas exchange.


Slow down your bisque firings, and make sure the local pickup downdraft vent is actually working as intended to get airflow.  If this happens to you a lot, don't cram in as much ware in the bisque loads.  If it is the occasional piece........ it likely was a happenstance of the way that one particular piece was located in the bisque firing....and comes under the category of "%$#@ happens." ^_^ .


Hope that explanation helps.





#43401 12 Inch Club

Posted by Benzine on 29 September 2013 - 09:06 AM

I suggest anyone, who accomplishes this feat, takes the cylinder, attaches a handle and uses it to drink in their awesomeness with their beverage of choice.

#40845 What Time Of Day Do You Fire?

Posted by Doulla on 15 August 2013 - 05:38 AM

We installed solar power a couple of years ago so I fire during the day. I set the timer to start at about 5am which means it is ready for the bung to be put in when I get up. I try as far as possible to fire on nice sunny days and my smaller kiln will fire entirely on solar power so for free!!

#38799 Have you ever used clay in mixed media pieces? | June 26, 2013

Posted by justanassembler on 13 July 2013 - 02:12 AM




#31019 Wanted to share this tile technique...

Posted by Paula Patton on 15 March 2013 - 01:18 PM

I found a broken light diffuser (grid) at our recycling center and tried a project I had read about before. I couldn't find the article, so I winged it and it worked out! I rolled a slab of clay out, pressed the grid into the clay all the way down and let it dry that way. The next day, tiny tiles fell right out of the grid!! It was like magic! No cutting, no marring, no sanding! They were all perfectly cut to the same size. I glazed them and can now make a great mosaic trivet or, if I make more, something bigger! There are other sizes of light diffusers, I just haven't found one yet!

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#18703 Was: Etsy or Ebay? Now: When Should You Start Trying to Sell?

Posted by Chris Campbell on 28 June 2012 - 09:09 PM

Just one last comment if I may ...
No one wrote that you could not sell your work until you had eight years experience.
The eight years I was referring to was the potential 4 years BFA undergrad and another 4 MFA since I assumed you would be training for your career.

The only advice I read from all of us was to make the most of this time in your pottery life when you do not have to make marketable work in order to pay the bills.
I don't understand why the message came across negatively but that's what happens sometimes on the Internet.
I hope you have a long and rewarding career in pottery.