Phil Hamling

376 County Route 1

Warwick, NY, USA 10990

e-mail: (change the -at- to @)

Zinc Silicate Crystalline Glaze Pottery

A chronicle of my recent progress and a way for me to keep it straight in my head!

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 Info I've been asked to keep in confidence.

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Crystalline Glaze Info

Electric Reduction Symposium
Molybdenum Crystalline Glaze

Friends' Work

8-2-12     .5% Black Copper Oxide, .05% Cobalt Carbonate, .2% Red Iron Oxide and .1% Manganese Dioxide







  Mo glaze recipe found in Sprechsaal, vol 122, No 4, 1989, written by Walter Kerstan. I do not know how it works.

7-20-12      Effects of titania content and hold time.


7-18-12      Gordon's glaze

7-17-12     This is the first time I've seen any crystals come from one of Sanders' recipes. At this glaze loading 3% MoOx seems to be the trick.

The crystals and iridescence are almost impossible to see unless in reflected white light. Studio Camera
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From at the barn:
Open Firefox on the laptop and go to
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It looks like 4 1/2% red copper oxide, 1 1/2% cobalt carbonate and 1 1/2% manganese dioxide is more than this wimpy ^4 glaze can digest.

7-15-12     Revisiting one of Herbert Sanders' ^4 recipes and trying to get the moly content right, plus looking at the influence of rutile in another.

I need to get some real kiln furniture for this small kiln. This set up includes reticulated alumina plates and sapphire bars. This test has samples with a line blend of from 0 to 4% molybdenum oxide.   A different moly glaze with 1.5% black copper oxide, .75% cobalt carbonate and .75% manganese dioxide and varying rutile content.

7-13-12     Yesterday Phil and I made a quick stop at the new building.





7-4-12     Feri has been making some tremendous work. It is good to see him back at it again. He has to be in that group of 3 crystalline artists.

One of my favorites Before and After A view from behind the scenes

6-25-12   I made a mixture of ~100g tin chloride + 100g isopropyl alcohol and used Jamie's booze bag to drip it in while I held the kiln at ~1200F by adjusting the hi - med - low knobs. I had to add ~40g water to get all the salt to dissolve. For the first 20 minutes it was going at ~ 1 drip per second, then for the next 20 minutes ~5 drips per second.

It smoked pretty nastily - I guess putting out HCl but I don't think there was enough reduction to make much of a reaction. Pieces had a white dust all over them which wiped off easily. I guess it is tin oxide. This silver containing piece seemed to change slightly and show some iridescence..

The green copper piece at 9 o'clock did not change. The partially red, previously reduced, copper piece at 11:30 seemed to re-oxidize and lost most of the red color. I'll do it again at 1300F with much more alcohol.

I recently spotted these at "Art on the Green" Savannah and Kat

I had to do some Photoshop work because Kat was wearing these ridiculous heels which put her up in the stratosphere making Savannah look like a dwarf.



Crystal Glazes, 2012, Hans-Joachim Wehnert. Stuttgart

Original German...........Rough English Translation

I took this down at Hans' request. I'm looking forward to when it is complete.

This silver containing piece was fumed with tin chloride.       
Andy Boswell has been making some great looking tea sets lately.  After raku (if that's a verb). 

Andy wrote: "Wow Phil, Your photos look better than the actual pots! It is amazing how a little bit of sunlight really gives that glaze the spark of life. Technically raku is a noun. Proper English would be to say "it was raku fired" but I know the words "I raku-ed it" have come out of my mouth and quite a few other potter's mouths as well. Andy


Spring is one of my favorite time of the year in the yard.  These are the last pallets of finished goods being moved from our old warehouse into the new place.


This is a good reason to bisque fire things. It helps minimize breakage in transit. Stuff from Jamaica.

6-1-12   We are going back to Jamaica for a while!




5-13-12  Maybe I'll just pack it in and concentrate on the bait and tackle shop.

  Molybdenum, disilicide heating element holders, Block fiber insulation and 2 sizes of finer insulated heaters. A sintering fixture for powdered metal components precision machined from an alumina fiber composite board. Although pure white when fired in oxidation materials like these, pre-fired in a hydrogen atmosphere, often take on a grey to charcoal appearance.


  Short Wave UV   Short Wave UV
  Short Wave UV   Short Wave UV
Natural Light + (a little) Short Wave UV Short Wave UV Natural Light  then Short Wave UV  
  Natural Light + Short Wave UV Short Wave UV  
  Natural Light + Short Wave UV Short Wave UV  


5-8-12  We are expanding at work. This new building will add an additional 50% to our operating space.

Hopefully we can get through this so I can move on to some studio time. I've only been able to get 5 to 10 minutes at a time into designing and building my gradient kiln for firing samples. It should help compress the crystal learning curve tremendously.
I know Frank Lloyd Wright didn't have a hand in its design.  It's hard to believe we started looking at this place 6 months ago and today is the big day - closing.   Phil took me fishing for my birthday on May 6. I was born 56 years ago on 5-6-56. All we caught were 6 sand sharks. This poor baby was "delivered" (prematurely) on deck.

5-3-12   The best tile was the one with the thickest, mud cracked glaze application.

  Patti and I celebrated our 25th anniversary with dinner at the Glenmere mansion tonight.
Now I just have to learn how to get these bigger and up out of the glaze catchers.

5-1-12    I finally pushed the START button again!

    Reconstituting dried glaze was a PITA. I had no clue what the water content was and the gelatinous effect of Veegum Cer was nowhere to be seen. The glaze application of 4 coats shrank and cracked like a pig.
Fuming with tin chloride lightened the pieces slightly and added a fringe of iridescence in the lowest temperature rings of copper, but gave essentially unremarkable results.   David and I gave Dad his final buyout check for the business. I can't believe 10 years went by that fast. Cole got his first tom this morning out back with Phil.

4-29-12   I read that fuming can enhance the iridescence of some crystals. So I got the stuff ans set the old oil bomb unit up outside.

Tin chloride, iron chloride and barium nitrate seem to be pretty nasty stuff. 20g of tin chloride Before Afterwards I saw a slight discoloration of the ceramic fiber block supports.

4-25-12      Mental note: Working on understanding "molybdenum glazes" with a group of collaborators has taken more time than expected.

A sad day indeed. Powellite crystals 4-28-12
I get a strange feeling from modifying other people's work.


      What were you thinking about 30+ years ago?


How Wizardly!     I guess he meant it when he said "I'll send you some tile to play with". of Marsha's unglazed pots... Alumina Hydrate and glue is the way to go. Flowering peach  

Anne Melvin wrote: "Hey Phil,   Here is a photo of one of Marsha's unglazed pots, picked at random off her shelf. I used to check out the proportions. One can also use the French Curve tool and the basic curve of the pot fits exactly. Anne" 

Pieces from the Ginny Conrow / Marsha Silverman Workshop


F413 base and 5% yellow uranium oxide with (from left to right) 0, 1, 2, 3 and 4% titania (back row) plus 1% green nickel oxide (front row). They've started planting onions. It's very dry. I've never seen the irrigation going in April before. Ceramic Fiber Settling Test


3-29-12 3-31-12  
We visited Bill Boyd on Galiano Island, British Columbia, Canada.
Click to see more photos from our visit.
Sturgeon Fishing on the Fraser River with Bill & William Campbell and Joe McKeen

3-25-12    Ginny Conrow / Marsha Silverman Workshop, Seattle Washington   Workshop Index

3-28-12 3-26-12 3-25-12 3-24-12
Throwing / altering demonstration and pieces from the first kiln firing. A little talking plus a full day of glazing. Helped setup, saw some sights and the evening slideshows. Got to Seattle at noon and spent the time getting acquainted.


3-18-12    "Molybdenum" crystals are illusive to say the least. Plus anyone with a clue has zipped lips.

    UV suggests they are not exclusively moly oxide.  
 Drippy white glaze tests with 20, 15, 10, 5 & 0% zinc oxide additions. . David Turner delivered this 5 DVD set on Sunday. Now all I need to do is get a DVD player and a free day to watch them Sushi Deluxe



3-16-12    Speaking of fishin'..... we plan to go for sturgeon on the Frasier River near Holly's, after Ginny's workshop and a trip to Bill Boyd's. I've got my license and sturgeon tag all ready to go.

Bill Campbell The Wizard Still cleaning up after Irene.

3-10-12    My fishin' buddy Bill sent me a bisque platter and some fired pieces.  If I want to grow up to be just like the best I see there's a long way to go.

Metallic Glaze Recipes

3-7-12    Still working with F413 glaze with red copper oxide, manganese dioxide and cobalt carbonate additions - with a few variations.

A new clay body with glaze containing my batch of F413 (2 on left) and one of the Wizard's F413 batches (after adjustments to get similar background) on the right. His 413 glaze comes out much darker than mine on that clay. I like the eyebrows. With  tin - indium oxide added.
With neodymium oxide oxide added.
With 11% red copper oxide and 10% manganese dioxide added viewed in 2 different lights.


  . Line blends in this area should tell a lot. Drippy white glaze tests with 20, 15, 10, 5 & 0% zinc oxide additions.


Finally......finally.....glazing some older work. Cuprous oxide (red) does not like to stay in the glaze. Test pucks of a high chromium castable alumina  refractory. My Toyota 4 Runner turned 100K the other night.
It has been an unusual winter with "warm" weather and little snow. I think a late fall application of Quicksilver for moss control is responsible for the odd blotchy coloration on the greens this year. The moss sure has been loving it on the rocks this winter.  


2-27-12 2-22-12    
I call this one "Clueless" Pictures of man made crystals by SurfaceNet. Thermal Technology, llc - Crystal Growth Technology web page


Avi's laps are also good for cleaning up the bottom of bubble alumina cylinders, like this one which will be on its way to a customer that grows industrial crystals. Bulldog Pottery.....Iron red molybdenum crystalline Too much something and not enough background?

2-18-12     Anhydrous Molybdates and Tungstates

Colorant Sources Revised colorant_sources_revised.xls


Did he call this glaze "Sunrise Blue" Or "Morning Blue"? AFU has a nice foamy kind of look to it.  
Uranium oxide engobe in carvings covered with clear F413 base glaze (left) and  F413 base +1% green nickel oxide (right). Left: F413 base with10% yellow uranium oxide + 1% green nickel oxide. Right: F413 base with 1% green nickel oxide. Both on uranium oxide engobe. Clear F413 base glaze on (L to R) yellow, orange and black urania engobes. Who said bikers are stupid?



Zinc Molybdate, SiO2 - ZnO2 Phase Equilibria, Calcium Molybdate, Calcium Tungstate, information.





2 Blue - New      
L to R: "bad" frit, 50:50 mix, "good" frit.    

A friend recently took delivery of a new batch of frit that plain old gave crappy results. It's just not the same. Glazes made with it come out over nucleated. It just didn't melt the same or grow crystals the same. The manufacturer says it matches their specifications but it just didn't work. Eventually a fix was found (I think by increasing the amount of it in the recipe, lowering the zinc and possibly tweaking the silica content). This formula adjustment process, I'm sure, consumed a bunch of time and money and caused many, many problems including agita.

I know this was after the fact but I ran a test to confirm the stuff was "bad". The 3 identical pieces above were thrown by The Wizard. They are made of the same clay and are the same size and mass. Triplets so to speak. I mixed a batch of this latest blue glaze using this problem frit and one with the frit I have been using, plus a 50:50 blend of the two. I applied equal amounts (weighed to within a gram of each other) to each piece and fired them side by side. I feel the results were conclusive and showed yes indeed the new stuff is crappy.




    Tonight's Firing   

2-6-12    Andy Boy came to play yesterday. It was Superbowl Sunday so we didn't get it all done. He came back today to finish up the last coats.

This piece has some nice carving in it.      When I fist met him I couldn't remember his name. Then I found some help in the refrigerator. 

2-6-12    NY Giants     Superbowl Champs

The fans were chomping at the bit for a Giants' victory. Eli Manning was coaching Madonna during the halftime show Bradshaw showed us how easy it was to win by just plopping your butt down over the goal line. In the end it's all about taking the Lombardi Trophy home.

2-4-12     Some interesting information on water crystals

Elementary Meteorology Online
Chapter 7 - Clouds, Precipitation, and Weather Radar

Ice formed overnight on a car. Here's a combo where the crystals fluoresce yellow.

1-31-12     After posting the question "Does anyone know Jon Dunlavy?" on The Crystalline Glaze Forum Greg Beckman (mohawkpiper) replied "phil, i know jon dunlavy. he works at the local clay store (clay planet) on saturdays and the rest of the week works as some sort of chemist working with glazes. ......... that piece you posted looks just like his work. G"

1-31-12     1-30-12
Does anyone know Jon Dunlavy? I found this photo on Flickr after searching for "Molybdenum Crystals" Here's another of his pieces I found on someone else's Flickr account.
Then I found his website but didn't see any molybdenum crystalline glazes.
Today, after everything had cooled down, the olive drab from the original yellow uranium oxide colorant is back. The most curious thing is that the original engobe sample, which was sitting wet for ~2 months, turned a bright yellow color after bisque - which is what I expected to see in the first place. @450C the sample using the original engobe, which appears yellow in the photo at the left, seemed to be an orange red color.
What a tweaky, fickle trail this seems to be!


1-29-12   1-28-12 pm  
Then I thought maybe my notes were flawed and I actually mixed them at a 20% level. While adding more powder I realized the yellow material I used in the second and third trial was from a  different container than from the first. I went back to the original stuff for this trial and made one trial using the original engobe. Although the 2 preparations looked different before bisque, afterwards the difference were unremarkable and still no olive drab. I remembered that the first time I mixed the engobes by hand and passed them through an 80 mesh sieve . The next time I blended just the uranium oxide in water first and passed it through an 100 mesh sieve (Y1 thru B1). Maybe particle size was the difference - so I went back to the original method (Y2 thru B2).
Patti and I went to see Andy Boswell at an exhibition in a gallery in Princeton, NJ. He had some very nice work there including some celadon green and blue glazed pieces.

1-28-12 am    My plan was "Today I'm going to go back to exactly the same clay combinations and see if I can reproduce my original results". Then I realized I had already tried those combinations and got olive drab so it must be something else ....... but what?

1-27-12     Jamie wrote "I’d say the (base clay) is definitely the difference, even if the engobe is the same. I notice differences in results when the body is different, even if it has the same engobe...."

1-24-12     I've been working with uranium oxide engobes and are perplexed by the results compared to my last attempt. I was expecting, after bisque, that the yellow engobe would turn to olive drab (as it did before) and the black to stay black. Neither happened. Although after bisque there were subtle differences there was no olive drab and no black. They just tended towards looking more like each other, in 2 separate kilns. I'm not sure what happened but would like to get a handle on it. This is one of the rare times I feel like I am unable to reproduce previous results.

Before After Before After
Previous experience from 11-25-11, left to right, 10% yellow uranium oxide engobe covered pieces turned to olive drab after bisque firing. Left to Right: 10% yellow, 10% orange and 10% black uranium oxide engobes on some of The Wizard's pieces. Left to Right: 10% black, 10% orange and 10% yellow uranium oxide engobes on vertical test tiles.
Some innies and an outtie. Engobe placed in surface incisions.    
    New bottles by Glenn Woods
 (I have to give him a real camera for Christmas.)
And one by Marsha Silverman who I can't wait to see at Ginny's in March.


I'm looking forward to this piece from Matt Horne. Joerg Baumoeller and Peter Ilsley in Joerg's studio. Photo courtesy of Josť Mariscal. An unique blue glaze by Paul Brown. Another interesting number.


This stinker took 5 firings. A post fire reduced piece of Gordon's. I wonder if the deeper gold crystals and pink background are from silver flashing from other pieces or if he added some magic ingredients in his glaze.    
  Now just to get this to stay on the pot!    


With the lid shut the Geiger Counter barely ticks.   Feri pointed me to this book on luster glazes Yellow, orange and black urania powders before (bottom) and after (top) a ^11 oxidizing crystalline glaze firing.



Bailey has a nice new SS barreled extruder which I set up on a quick disconnect mount. Fabricating a lead lined ammo can, with copper foil liner, for storing uranium oxide powders.



Back to Crystalline Glaze Information Page

Recently I had the good fortune of importing many very interesting crystalline glazed pieces from Beijing, China.

The source of all my good fortune---my day (and night, 24 - 7) job. ZIRCAR Ceramics, Inc.
One of my other passions - landscaping, gardening, greens keeping, etc..