Jump to content

Crystaline Slow Cool Commercial ^6 Glaze


LeeU

Recommended Posts

Any idea whether regular commercial ^6 matte or gloss glazes, or commercial ^6 underglazes can be mixed, and/or put under or over, commercial slow clool ^6 glazes with crystaline features? Especially near white in color or with some translucency (ex. Coyote's Ivory Crystal)? I know-test-test-test, but before I spend the money--and it does cost-cost-cost, I thought I'd ask first if anyone has any feedback based on experience. This would be going on greenware for single fire unless bisque is really required for some reason. Thanks in advance.

Link to comment
Share on other sites

I would say no just from my past experience with crystalline glazes (MFA thesis topic) . 

The crystalline glaze is a zinc base and very specific chemistry to make crystals. Combining with another glaze would change everything. 

The glaze must be very fluid to begin with. Adding something else would change that too. 

I am sure Glazenerd will chime in here.

 

Marcia

Link to comment
Share on other sites

lee, why not go to the source and ask the glaze manufacturer.  crystalline glazing is so complicated that the maker of the glaze must have done something special to make a glaze for the usually ignorant (not an insult, just an observation on education) public so they can use the product safely and be back to buy more.

Link to comment
Share on other sites

Lee:

Marcia covered the main points pretty well I thought. Crystalline glaze has a very specific chemistry, and the chemistry from typical glazes can and will interfere with it. At cone 6, there should be 3-4% (dry weight) of lithium carbonate; which would make standard glazes excessively fluid. You can however glaze the upper portion in crystalline, and allow it to run into standard glazes below.

 

Black Clay with crystalline glaze.

 
** clear glaze on black clay below the crystalline on top**
Post a link to this glaze, let me take a look at it.
 
Lady: actually crystalline glaze is not that complicated chemistry wise. 3110 Frit, zinc, silica, lithium and titanium seeding agent. There are certain color combinations that are more predictable result wise than others: which is all this manufacturer did. When potters try to tweak or improve the basic recipe is when the results change: and usually for the worse.  It is the firing cycle that is complicated; and attempting crystalline glaze without a kiln programmer is nearly impossible.
 
Edit note: about a year ago a potter was asking about this type of glaze. Do a forum search for crystalline, that topic should come up. I recall talking about it rather extensively then. If you want to proceed, PM me and I will help you as much as possible.
Link to comment
Share on other sites

(It is the firing cycle that is complicated; and attempting crystalline glaze without a kiln programmer is nearly impossible.)

 

This is not may area of expertise but I will add that crystalline glazes have been around long before programable kilns. Not a big deal but they can be done in gas kilns at cone 10 or manual electrics-the thing is its not easy and takes work with a pyrometer to get the temps/cycle right.

​I have friends who did this in the 70's and 80's long before programable kilns came along. Of course thats about all they did -cystalline glazes that is.

Now its much easier with computer programed kilns.But you can still grow them without that-its knowledge of the cycle of temps thats key.

Link to comment
Share on other sites

I agree, Mark. I did my research and production of crystalline glazes in the early 70s. I research the library at U of Ill. Ceramics Engineering in the basement where there were kiln logs and notes from the early 1900s. Great source of information. I used a pyrometer. In the early 1900s Adelaide Robineau's husband, Sam, fired her crystalline glazes by eye. Later went blind from that. There were some amazing glazes created in the Arts and Crafts era around central Illinois and St. Louis.

Marcia

Link to comment
Share on other sites

Mark:

 

Note: I did not say impossible; I said nearly impossible. If you want to sit in front of your kiln from peak, through all the ramp hold cycles (4-8) hours: you can do it. Add to that, a 3-6 month learning curve for adjusting crystal temps, learning fuel control adjustments, etc.

Perhaps I should have stated: it is nearly impossible to find a modern potter who has the time and patience to learn how to control their gas kilns in order to grow crystals. The fact that only 4-5 members among a 29,000 member forum who have even attempted crystals sums it up pretty well. If you think zinc crystals are tough, try growing molybdenum crystals.

 

Marcia: the University Museum where Taxtile Doat worked still stands, and his pieces on display. 1905-1917? Dates are close.

2nd. Edit: first crystals were grown sometime in the 1880's, if memory serves. Taxtile Doat working at Limoges is considered the father of modern crystalline glaze. When Louis Tiffany discovered them in an exhibition, they became prized pieces during the Art Noveau period.

Link to comment
Share on other sites

I thought Taxile worked at Sevres. he is one of my heroes...he worked with Adelaide Robineau at the Women's University in St. Louis in the late teens  1oo years ago.

I know he did at some point in his career and wrote grand feu ceramics..I have a copy.

PS I still have some molybdenum!

 

Marcia

Link to comment
Share on other sites

Back to LeeU's question, let me add to Marcia and Nerd's comments something about stains and underglaze colors. Some of the students in my crystalline classes have tried different things with stains and underglazes, and most did not have a desirable outcome. If these commercial crystalline glazes are truly zinc orthosilicate crystallines, then the caustic glaze base will attack the underglaze or stain  and draw the colors into the crystals in the usual order of precedence, leaving behind whatever is left over. For example, a blue stained slip or underglaze intended as a background will not remain blue. The cobalt will be leached out into the crystal leaving who-knows-what as the ground. Further, many stains (and probably underglazes too, there is less manufacturer data about underglaze colorants) rely on chrome green in the color production. Chrome and the zinc in the crystalline glaze do not play well together.

Link to comment
Share on other sites

Marcia:

You are right, it was Serves.... could not remember exactly. I had in France.. that count.. :) I have a lb. of moly out there myself. I have made a dozen attempts or so....all I can say is -------.I have a decade of firing only crystalline glazes, and moly still drives me insane.

 

Dick:

I try hard not to do information dumps anymore, but thank you for adding just a glimpse of the daunting chemistry involved. I could add several more paragraphs, but that would serve no purpose. Easy to talk about crystalline, another thing to dive into the crystalline rabbit hole. ....and it is a deep one. Took me almost two years to get control (laughs) over formations.

 

attempting crystalline glaze without a kiln programmer is nearly impossible.  by which I meant, you have not fired crystalline before .Still trying to figure out how people read things in, that I do not say.

Mark: I only know of two guys who fire crystalline in gas kilns, and both are old school potters: 40+ years.( 2 among 10,000 gas kiln potters??) There are many who do reduction fires in gas, after they do the primary crystalline fire in electric.

 

 

 

Nerd

Link to comment
Share on other sites

 

PICT0414.JPG

silver nitrate reduction by James Fox. C@ James Fox.   Jim is one of  two potters I know who fires crystalline in gas kilns.

Jim does some amazing reduction work, some of the best I have seen.

 

Moderator Note: this image has been marked "public domain/public viewing: by its copyright owner: James Fox

Link to comment
Share on other sites

Glad I asked!!!   I have a programmable electric kiln and will follow the slow cool guidance for firing this particular glaze--without thowing in other glazes! I am so averse to chemistry these days, and due to certain "issues" of Self, I absolutely must keep my entire clay-world as simple and rudimentary as possible if I am to stay in the game. I so much appreciate the freely shared info and experience in these forums, with never-ever the slightest whiff of negative judgment of someone like me who just is not going to dig deep at this point, and who is often looking for the easier, softer way LOL. Thanks! All "youse guys" are treasures! 

Link to comment
Share on other sites

Nerd I was a just pointing out that this type of glazing has been going on long before programers where on electrics. I have a few crystalline pots and they where done before controllers. Controllers have made this a much easier effect for potters theses days .You can even buy this glaze remade now.

 

I even know a few potters who only do this type of work.It sells ok but has to have high price point as its so time consuming.I have only personally known gas potters doing this work.One dream may use an electric-I will ask them next week .I recall they said gas kilns but that was a decade ago.

You can goggle one dream ceramics they are all crystalline work-sinks to bowls a whole line of this work. We do many of the same shows.They will be my neighbors at the Big show next weekend as they to have a double booth next to my double.

The thing is the process is firing pots on pads and grinding all the bottoms smooth as the glaze runs off. A soft brick make as a great pad. You will need the right grinder setups to smooth the bottoms.Nerd can spell this process out better.

Link to comment
Share on other sites

Wow, that is a beauty by James Fox. One of mine with Molybdenum and cobalt is in the Illinois State Museum of Art in  Springfield. I will look for an on image. Midnight blue with bright blue crystals. from 1973 Illinois State Craftsmen show, Purchase award.

smaller scale crystals but the color was beautiful.

 

Marcia

Link to comment
Share on other sites

Mark: now I got it.

 

After WW 1, crystalline glaze disappeared off the open market: there is no historical record of it. Herbert Sanders (I believe) was responsible for reviving it in the 60's. Crystalline glaze took hold more in the UK/France area before the potters in the US started. There were but a small handful in the 70 and 80's. It was not until the 90's and the advent of controllers that crystalline became more accessible. Even now, I would estimate somewhere in the 600-800 potters worldwide who actively fire crystalline: with others who dabble with it from time to time. Although, it seems be gaining traction, and those numbers will increase (and probably already have.)

 

Historically, like Marcia; Taxtile Doat stands out to me as being the most adventurous potter of his time. (1880-1920) I always wondered how he figured out what the recipe was, and how to fire it? There was no one before him firing it, no glaze calculators, not even kiln sitters: how did he figure it out? He fired in a three story bottle kiln that was like 1000SF of so.? Took three days, men manning shifts around the clock to fire it, and up to four days to cool. He fired crystalline and other specialty glazes in large saggars. I have his original recipes for crystalline, which read way different than what we use today.....no such thing as frits back then.

 

We sit in these forums hashing out formula and techniques: Taxtile Doat and Maria Longworth Storer invented them. How did they figure it out?.... boggles my mind to think about it.

 

Nerd

 

Edit note: Marcia: I wish you or one of the other female potters would write a book called: "Women in Pottery." Tracing the contributions of women in the pottery biz. I think some would be shocked to learn that it was women who invented a lot of the modern techniques used to make and decorate pottery. Maria Longworth Storer (Rookwood Pottery>) 1890-1920's. Adeliade Robineau.  etc. ... thinking my spelling and dates are close.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.