Zinc Silicate Crystalline Glaze Pottery

Phil Hamling



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Ian's Glaze

Pickling.....Crystalline Glaze Factors - Pickling Solution

Dr. Arnie's 644 Base

Andreas Widhalm's Porcelain


Fallonator Firing Schedule Grapher .... firinggraph_8.xls

Paul Lorber Red Recipe        Paul's Piece

Terry Fallon
secret/terry_fallon/ Fallon gold.xls secret/terry_fallon/ Brown Eyes.xls

The frit 007 is DE powder  

The DE powder I use is pool grade its 86% silica, other DEs from feed stores or garden supply may only be 40% silica with as much as 20% calcium   

Kris Friedrich's Glazes.......Kris Friedrich

Fallonator Picasa Web username philhamling, password terryfallon

Red Copper

Gordon Czop

Lasse stman, potter. Stoneware and Porcelain. Glaze list

     Russell White    

John Tilton's porcelain

Ian Childers Before and After

Kris Friedrich Fusion 644

Denis Caraty

Jamie Koslowski

Michael Eastep

Dick White Re: F413

And here's another of mine that worked very nicely on the first try.

Richard the 3rd:
Fusion F644 - 41
Zinc - 24
Silica - 27
Ghastley Borate - 1
Lithium Carb - 3
Titanium - 6

(And if it looks vaguely familiar to anybody, it is an adaptation to ^6 of Peter Ilsley's Base I favourite on p62 of his book...).

Here's one from a small load on Thursday (some mugs, which didn't work as planned, and some more vases...). This one is 9" tall with most crystals 2 -3" across. It was more of the now-infamous Richard the 3rd, fired to cone 6/7 (2200F max, but my kiln crawls at that temp so cone 7 was soft).



http://www.puttgarden.com/crystal/KANTHAL ELEMENT CLC.xls



Jesse Hull & John Tilton on Reduction

Steve Davis Copper Reds

Element Analysis.........................L&L's Analysis.........Dialogue with Steve Lewicki..............L&L's Proposal to Jesse............Jesse's dialogue.....More Dialogue with Steve

Steve Klinski (Uneven Firing) Large plates and bowls fired in my large gas kiln have been turning out pretty nice on the inside, but spectacular on the outside. Is it because ....."




Hi Steve,

The outside of your bowls have enough draft to allow the glaze to shear enough to behave like a vertical surface. The inside doesn't and is behaving like the horizontal surface that it is. You might like to try slightly different versions of the same glaze for the interior and exterior. Adding 3% flux to the interior glaze may be a good starting point. Good luck!

On all our flatware we increase the glaze amout by 50%, fire to a cone hotter (^11), and the last ramp goes up at 115F per hour to top temperature. Hope this helps.
Best, Kris (Friedrich)

Digital Fire Ceramic Articles Database

The test tile and the pot have the same look to them, I'm pretty sure I made them at the same time and the clay in the tile and the pot are the same.
I reviewed my notes tonight and the way I believe to make it is:
-Make an engobe using a thick slip of Tucker's HHP. This is one of the 2 types I sent to you. Add 10 wt% Cerdec Degussa Inclusion Stain # 279496 (Brilliant Red). (Do you have this stain or should I send some?) I determined the solids content of my slip by drying a 15 gram sample in the microwave. Mine was 42.7% by weight.
-Apply the engobe to softish leather hard pieces . I think the thicker the better, but at least enough to cover. Make it nice and smooth.
-Make the glaze with
51.8 3110
24.5 ZnO
1 Rutile
1.2 EPK
14.4 Flint

(Adds up to 92.9)

1 Nickel Oxide

1% CMC
I added 400 ml H2O to a 5X batch
Glaze and fire the puppy to ^10.
My holds were  1 hour 1050C, 3 1/2 hrs @ 1080C, 1 hour @ 1000C and 1 hour @ 900C


5-18-05 John Mankameyer http://www.crystallineglaze.com/index.html

73 year old? Been doing this since 1973 - used to be electronics Engineer. Lives with 102 year old mother in Montana. Formerly lived in California. Every firing is an experiment. Herbert Sanders PhD, Syracuse Ebberson Museum told him 20 years ago he has mastered crystalline glazes and it's time to move on.

Uses Pemco 283 frit. Unavailable for 10 years now. Has 500 lb. from original 3000 lb stash. Claims 3110 is too shiny for his taste. Uses Mile High Ceramics "Zen" porcelain. Fires between 1500 and 2000F. ^10 flat, ^11 1/2 way down then drops to 2000F. Agate look is formed by ramping down to ~1600F then coming up again staying on low end. First he said 1500F, then corrected it to 1600 and added if you go to low you may stop the crystal growth and can't get it started again. Multiple times? He fires at low end of crystal growth range to get rounded crystals. Higher temps yield larger, but spikier crystals. He's made some 5" in diameter. Used to go for size (when he was younger). Now goes for Agate look. He uses a 2.3 cu ft Cress kiln with 2 1/2" brick. Fast kiln. Has rebuilt many times. Winds his own elements. Canadian wire? Gets ~40 firings per element. Fires everything by hand. No programmer. Reduces in this kiln. Adds oily rags.


5-18-07 Jay Dubiel (collector) 434-575-5781 called saying he has one of everybody's except mine. Wants Chris Groat purple vase. Couldn't believe it's not for sale. Kept asking "why do you do it if it's not for sale?"

Avril Farley
2 Bayhead Cottages
Lower Soudley
GL14 2UD
United Kingdom

Tel from states (UK  international code) 594 823241




 I packaged 3 1/3 kg Ferro 3110 in 3 each 1 gallon plastic buckets (for a total of 10 kg) and sent it via the United States Postal Service's "Global Express Mail" this morning. They guarantee delivery in 3 to 5 business days. Hopefully you'll get it by the end of the week. This service cost me $107.25. For ~$5 less I could have gotten their 5 to 10 business day service, but figured you could use the material right away. The USPS Label Number is EB201949993USThe Customs Declaration Form is # CP970396662US. I will hold onto the paperwork here. Please let me know when it arrives. I labeled it as a gift (a birthday present). How old are you.....28???

 I looked at UPS first and the price was insane! It would have cost ~$200+. I am sure DHL would have been about the same.

 This turned out to be more time consuming than I had expected, but if it helps you out of a bind that's great and hopefully you can be my "Knight in Shining Armor" someday.

 As far as "any preference for shape/size/colour"  is concerned I have 5 requirements of the piece(s) you send. They include:

1) It is (they are) beautiful

2) It is (they are) beautiful

3) It is (they are) beautiful

4) It is (they are) beautiful

5) You made it (them) so I will always have something I look at and say "Man, isn't it (aren't they) beautiful! It (they) was (were) made by my good friend Avril Farley.



No problem. I can send it Monday. Is your ship to address on your web page? Can you copy me regarding your answer at work too? My e-mail is pdh@zircarceramics.com I'm sure I can send it FedEx or DHL. I will call it a gift, but probably will have to declare some nominal value. If you want to pay me, how do you feel about sending some of your work, as a gift of course? Phil

-----Original Message-----

From: Avril Farley [mailto:crystalpotter@btinternet.com]

Sent: Sunday, April 08, 2007 5:06 PM

To: Phil Hamling

Subject: FerroFrit

Phil, that is so kind of you. I would be very very obliged if you could send me 10 kilos. of FF3110. How can I pay you? International money order? Credit Card? let me know please. If you do send it can you call it a gift,

please. Best wishes Avril

Phil, the recipe for this glaze is 3% light rutile and 1% cu carb.  The iron came from the rutile, although Limoge special porcelain is also in itself quite high in iron. This would have been fired ( as I remember, my recipe book not being to hand) in a 1250 firing,  coming  through  a crystal forming period of about 5 stages the last of which would have been a slight raise, probably from 1045c up to 1055 for 10-15mins.  Unfortunately since I ran out of that particular batch of rutile , I have  come near to , but not  able to reliplicate the exact results for this particular combo.

Best Avril

Phil, For encouragement, this is an example of a three times fired 15" flat dish - one of my best early pieces which started out scaled - there is a particularly nice huge crystal in the base.  I often refire, it is surprising how  things can get better. I like Jesse's idea of the hole and 'jewel' base.  I've not tried this but may now.
Jorg, Welcome. I am not sure what you mean about 'blank spots' but this is the result of 3% strontium (which I use as a substitute for Barium) and 2% cobalt in my FF3110 base glaze.
Avril in the forest UK
Terry Fallon



Terrence Fallon
875 N.W. 65th Ave.
Plantation, FL 33317

Cell: 954-444-6983

Home 954-321-1403



3071 N.W 64th AVE


Terry's Work

ramp up as you like to 1990f and add hold at this point for 10 minutes or longer to reduce number of crystals, the glaze should be completely melted at the start of this hold if not increase up to get full melt
400f up to 2350f hold for 15 minutes (yes 400 not 9999 to fast)

9999 dn to 1840f hold 15 minutes this should take 30 to 40 minutes.

50 up to 1980f hold 10 minutes (nice round crystals if glaze is not to thick, more flowery and transparent where thick. More flowery if over 2020f

9999 dn to1840f hold 50 minutes this gives a halo


new mix 02-21-2007.xls Use "Rainex" to improve shine and "POP" of finished pieces.
Blue on an orange ground is primarily nickel by it self, try 2% Nickel Oxide or carbonate
to get more orange in the ground add manganese dioxide, more yellow ground add black iron, green in the ground add cobalt.
MOST  IMPORTANT  KEEP   TITANIUM  at less than  2% and maybe less than 1%
Titanium makes nickel turn either brown or green you will not get blue crystals with the 8% tio2 in your base glaze!
for your eyes only

 Glazing lids for that all over effect.
#1 cut the end off a ceramic stilt, needs to be the ones that have steel pins. Shape to 3/8 square with pin in the center.   
#2 need a stand to prop lid in the air and to catch drips if they occur.
#3 glue square stilt pin on top with the Kaolin glue as for glaze catchers

#4 glaze inside and out of lid go easy on edges that might drip. Balance lid perfectly on top of pin check for level ( must be perfectly level ! ) Fire as usual, I fire to 2350f without a single problem yet.



A little lithium with iron will make the iron "Pop" and bring out the gold color.



I do have some new greens. Some low holds. first halo1800f , second halo 1750f last black halo 1690f

ps. FallonClassic clay


Mr. Phil
I thought you would like this one, you like green.
Im making pieces for when I get my reductionator going again.
3% Lithium Carbonate
if you don't ball mill don't use it
3%  Alumina Hydrate
(you could use 10 or 12 % Spodumene for the lithium and alumina just cut the sio2 a little if you do or use 6% Spodumene and dont worry about the add alumina or cutting the sio2.)
2% Titanium Dioxide
4.5% black copper oxide
1800f. 10 min
1950f  10 min
1850f  30 min
1950f   5 min
1800f  30 min
200f down to1700f 10 min (all four last halos come from this ramp) black ring, brown ring, light tan ring, last black ring.

Very nice! Are you linking 2 programs to get all these holds? The last 4 rings are real cool. I wonder if you went down from 1750 to 1700 @100F/min., held for 20 minutes, then repeated it if you could make them broader and get them to repeat broader green, brown, white, black rings?
I just took some sneak preview shots of last night's load. I'm putting them up now.

Mr. (   )

 Latest one out the kiln.
showing firing schedule the low holds give a very light color but only when followed by a hotter one, an increase in the hold time from 10 min to 20 min did not increase the width of the halo.
this base has 10% 3134frit and only green nickel carbonate 2%


William Melstrom Forum Password: Sc00ter


Denis Caraty


A very good and reliable white liner:

Custer feldspar 34.7
Dolomite 19.6
Whiting 3.1
EPK 23.6
Silica 18.9


The colorants for the purplish glaze are 0.42% Co (carbonate), 1.0% rutile and 1.33% Mn (dioxide).  This is a super secret recipe, and although I know that everyone is going to get different results, I don't want you to share it.

The key is the Mn, which can do very weird things, such as blush reddish, in the right conditions.

 That glaze is the basis of my super secret "ruby."  Where POOLED, it usually turns ruby or orange when STRUCK

These are before and after pictures.  Note that where the glaze pools in the first pic it becomes an unappealing transparent grayish-blackish purple-blue.


Phil, Here's my base:
 3110    38.29
zinc ox    19.1
Ball clay    1
silica    16.77
titan. diox    4.76
bentonite    4.5
CMC    1.5
 does not add up to 100.
-- William

-----Original Message-----
From: William Melstrom [mailto:william@handspiral.com]
Sent: Sunday, March 04, 2007 10:58 PM
To: Phil Hamling
Subject: Re: Post 1098

My final segment is a long hold at 1000C.  My cooling consists of rate 85 to 940C, then rate of 60 to 800C, then I crack the kiln.  That's comparable to your 2 hour cool down ramp.  The difference in color remains inexplicable to me.
When I'm striking, I usually have plates, so my strike rate is extremely slow to avoid fracturing.  Rate of 65 to 690C, then a fire-down of rate 65 to 300C, then off.
-- William


Horizontal Firing


I was trying to remember what you told me regarding changes to make when firing horizontal ware and am drawing a blank. Did you say to lower the growth hold by ~40C? I thought there was a 2nd point but feel like an Alzheimer's victim.




to avoid the spikiness, and get back to nice, round crystals, lower "all" (if, for example you have a schedule with growth rings) of your lower temps by 35 degrees.  Raising the peak can also sometimes reduce spikiness.  Lower your overall growth time so some background remains.  Lots of people have tremendous problems with pooled surfaces.  It might take a lot of work.

-- William


William uses Coleman porcelain

Fast firing up and down in ~8 to 9 hours. Important to have 1/2 hour hold at 800C to prevent bloating.


Dwight Dwight's comments on Chris Groat's work


Chris Groat
1809 Nottingham Rd.
Greensboro NC 27408




Chris Groat
St. George's University
School of Medicine (PO Box 7)
St. George's, Grenada
West Indies


Hi Chris
A vast majority of my work is flatware and bowls. I am very familiar with the crystals at the bottom of your bowl. It took me a long time to figure out how to get good crystals in a thick flat glaze. From what I can see it looks like the crystals at the bottom are underfired by about a cone, maybe more. Glazes on flat surfaces require more heat or flux than on veritical surfaces.The crystals on the side look only slightly underfired. It's not hard to both underfire and have all your glaze run off at the same time. I'm a big fan of peeking during my firings especially when I'm using a new formula and I know that glazes begin to sheer long before they finish boiling and smooth out. A slow ramp to the top can give you both a thin and underfired result. If your kiln is up for it you may like to increase the speed at which you reach the required melt. Judge your melt be cone not temp. readout.

On flat pieces I raise my temp. at 80 degrees per hour from 2100 to 2350 then soak until ^12 is nice and flat. The I drop to 2150 and soak for 35 minutes then drop into the crystal window. This with a ^10 glaze. The result is a thick sea of glaze with nicely shaped crystals with good seperation floating on the surface.

With bowls I load the majority of glaze at the rim with just a paper thin coating to the bottom. I ramp up from 2150 to 2350 at 600 degrees per hour then hold until ^10 drops then crack my kiln 1 inch and drop to 2150 where I hold for 35 minutes to desolve seeds then drop naturally into the crystal window.

I've found that although good for plates and bowls, both of these firings are pretty much worthless for vases.



John Tiltons Glazes




I just chose a very simple schedule as we were pressed for time and I wanted to be able to show some principles.
I think the schedule was:
150 to 150 hold 20min
265 to 2350 hold 0
9999 to 2000 hold 2 hours
9999 to 1850 hold 1 hour
Cool. As in cool the kiln.
In this way you can see that:
1>There were 2 main places where the crystals were growing.
2>But there are more than 2 places where the crystals were growing so they had to be also forming as the kiln was heating and cooling. That is, the crystals are also forming as the kiln is trying to get to the temperatures we have programmed. We had a lot of pots in the kiln (I like to fire with just a few pots) so we were not going to be able to get to a different temperature quickly.
3> Crystals are different colors at different temperatures. The soak at 1850 was to put a ring around the basic crystal. I think this is really important as it allows someone who is energetic enough to know what colors any particular glaze can give.

John on crazing

Hi Anne,
Crazing is the result of the glaze shrinking more than the clay in cooling. The usual way to look at it is to either add silica to the clay or to the glaze. It is always easier to add silica to the glaze, so this is where we start. By adding silica to the glaze. It usually works and you are done. But sometimes it doesn't work and here you have to change the clay body. But you did change the clay body. I'm going to guess that the Minspar has less silica than the Kona. Yes, it matters. Which Kona are you talking about? However, you have some samples that crazed and samples that didn't. What is the difference? You will notice that TiO2 and SiO2 are both O2s. By adding titanium you were adding something that acts like silica and this is the reason that your glazes did not craze with the rutile. It should also give you an idea of how much silica to add to fix the crazing. My suggestion is that you do a line blend of silica into your glaze. Pick one of the crazers and add 2% silica to it 5 times, glazing a tile each time. My guess is that by 8% you will not have any crazing.

Anne Gary wrote ;
I am baffled. Some of my vases have crazing and others do not. Same base glaze fired on the same program to 2230 (cone 8 at 9 o clock when done). They are applied to the same slip cast body.
 The glaze recipe I use is Fara's BORY 1 Recipe
> Ferro Frit 3110 50
> Zinc Oxide 27
> Silica 16
> Titanium Diox 4
> Gerstley Borate 3
> The slip cast body is:
> Kona F4 20
> Minspar 16 (supplier ran out of Kona and substituted Minspar, does this matter?)
> Grolleg 31
> Flint 200 17
> EPK 15
> Bentonite 1
> This crazed sample has 1% tin, 3% Ilmenite, 0.5% cop carb
> http://i177.photobucket.com/albums/w235/annegary/IMG_4268.jpg
> Next crazed sample: 1.5 cop carb, 1.5 cob carb
> http://i177.photobucket.com/albums/w235/annegary/IMG_3019_1.jpg
> Crazed sample: 1.5 nick carb, 1.5 cerium
> http://i177.photobucket.com/albums/w235/annegary/IMG_4362.jpg
> Uncrazed sample: 4% rutile, 1% Ilmenite, 3% Cop Carb
> http://i177.photobucket.com/albums/w235/annegary/IMG_4377_1.jpg
> Final uncrazed sample: 4% titanium
> http://i177.photobucket.com/albums/w235/annegary/IMG_4190_1.jpg
> Should I tweak the base for the crazed glazes. What would you do to it to stop the craziness!
> Last question, is there any way to not have crazing on the bottom of a platter. If there are not crystals covering it, I always see crazing.
> Thanks much for the help
> Anne
> On my 25th firing and looking forward to John's workshop in February!

Post Firing Reduction Dialogue


Bill Schran

I plan on setting some of my fired crystalline pots aside for some post firing reduction - firing in a small gas fired updraft kiln to a lower temperature.
I've read various information in the past about reduction firing in an electric kiln during the cooling phase, but I'm not keen on introducing combustibles into my electric kilns.
I was thinking the 1600 - 1800F range with fairly heavy reduction (flames & smoke like back in the old days of firing kilns) but suggestions for a target firing temperature are invited.
I will need to get the glaze to the start of melt to allow the carbon monoxide to react with the oxygen contained by the copper, but not so hot that I reach a temperature that would affect the crystals.
Any suggestions for percentage of copper in the glaze?


According to Peter Illsley take the kiln up to 800c then slow HEAVY reduction to 600c then pray.

For post-fire reduction:
Have a good talk with the Kiln Gods
Come up slow in oxidation so as not to stress the pots to 800c
Put it into heavy reduction by restricting the primary and secondary oxygen intake and the exhaust
Heavy flames should be shooting out the exhaust.
Be careful of a flame-out!!!!
Reduce temp slowly to 600c
Shut it down and close it up
Have a good talk with the Kiln Gods


Larry Anderson

I have had my best luck in the .5% to 2% range of Copper Carb. Varying the reduction time from 45 minutes to 10 minutes can yield some nice variety also. Try it with a high Titanium glaze with no colorants and see what happens.

As Avi mentioned, Peter Ilsley suggests firing down from 800 C to 600 C (1472 F to 1112 F). I think it is important to make sure you finish at a low enough temp. that it cannot reoxidize at the end.


Holly McKeen

try also adding a small amount of copper to a cobalt blue glaze, and if all is well with the kiln gods, the copper may go to the crystals for red on blue. Good luck.


Jesse Hull

c/o Wiseman~Marie Ceramics
8399 Roelke Rd.
Blue Mounds, WI 53517

You already have the basics... beyond that there is no simple "how to".
The obvious first hurdle will be in finding the peak temp. for your glazes.
You should reduce at the highest temp possible. The higher your glazes will let you go, the deeper the reduction effect will be achieved INTO as well as on the glaze surface.

*Here's a short cut*:
The quickest and easiest way to find the peak temp. to take your post-fire reduction kiln up to is to ...not fire it.
Although the reduction atmosphere will have a marginal effect on the glaze softening, you can find your temp. maximum more simply by using your computer controlled electric kiln. By programming successive firings, you can find this w/o having to manually fire the gas kiln. Once you've established the highest temp you can take your glaze to before it's aesthetic is ruined, you can reduce at the highest temperature beneath that. That top temp is going to be defined as much by your own opinion as anything else. I personally like the "dryer" matte surfaces I've been getting with post-fire reduction as much as the color effects:

It took me 3 firings to find my own temperature window for just one base glaze, and that will vary with additions of titanium, colorants, etc.
We've already had conversation threads concerning outside temp's, wind gusts, and barometric pressure... all those extra variables sometimes just make you look at the firing results, then your own notes, and just laugh. No matter how much you learn, the kiln gods will always have the controlling shares.
Even after all this, experiment within the entire temp range and with varying amounts of reduction. Believe it or not, the following pictures are the same glaze recipe:

Last mention:
If your kiln is outdoors or in an unheated enclosure, take advantage of the cooler part of the year. The quicker you can drop out of that temp./ reduction window, the less chance you have of the glaze re-oxidizing...

i am planning on learning crystalline glazing (i must be mad ) Welcome to the tea party then...
The most common frits I've used or currently use in the ^8-12 range are:
Ferro 3110, 5301, 3304/3403, 3485
Degussa 90208m
Glostex GF-106
Fusion 75, 413, 466, FZ-24
Pemco P-IV05, P-1084
Mondre and Manz 4067, 1233
Some of the frits listed above can be direct substitutions for each other (3110=75=P-IV05, GF-106=413, 90208m=466, 5301=FZ-24=P-1084) and some are no longer manufactured, although there are quantities still around. Not knowing what's available to you, I listed them all.
I've also used Ferro 3124, 3134 or Hommel 14, 90 as additions to the frits above to get certain results, but because of their boron content they may not produce the best when used alone.
Frits are easier to work with, but aren't your only solution. As far as raw material fluxes, I've used Sodium Carbonate, Kona F4 Feldspar, Potash Feldspar, Sodium Silicate, and Nepheline Syenite along with additions of Lithium, Strontium, Barium, and Calcium Carbonates.
Use Peter and Fa's books to guide you in the initial use of these materials, and then expand on your own as soon as your comfortable with what each does.
Go crazy!

Purple.........Hey Sherry-

Try these as line blends:

1st) Small amounts of manganese and cobalt (less than 1% of each).

2nd) A blend of Erbium and Neodymium offers shades of translucent purple... -I avoid titanium with lanthanides for "cleaner-looking" results...

3rd) Kris gets some of the nicest deep purples I've seen in his Geil with blends of iron/manganese-bearing titania (rutile and Ilmenite) in reduction. Plain titanium (at 6-8% total) gives a nice soft purple.
I've been getting these various forms of titanium to go purple using post-fire reduction as well. Silver with rutile often yields a pinkish purple.

These are starting points, have fun!


Kirk Morgan

17340 Bridgewater Circle

Minnetonka, Mn 55345


yes of course--4/11 I'll be home about 7pm cst or tonight till 9. As you can imagine my time is messed up. Or I can call you.   952-449-0926 home or work 952-993-1950 or beeper 952-231-4268. You should be interested in how this fluorescent thing happened.   Kirk


Not just yet on the photo. These pots are going to the Thomas S. Warren museum of Fluorescence in New Jersey and I'm working on an article for Ceramics Monthly in the Up Front section. I was going to wait until I hear back from them. It was your site that got me experimenting with this area--the red in the pot comes from Samarium-a rare earth oxide-but it does not show much. The fluorescent mineral collectors are very excited by these pots and since you have to have an expensive light to view them they might be the only ones who would buy them. Your daughter Katerina does get the prize. The crystal structure that you see under short-wave UV is much more than you could ever see in light. The light is coming out of the crystals---truly amazing.
The pot in light for you to see.  Kirk

This is Kirk Morgan in Minneapolis,Minnesota. I remember my son when he was 6 we went to San Diego during winter and as we were driving he looked at us and said "are we still on earth".
So the cracks are upon you---I agree that slow drying helps but you still see them after the cone 10 fire. Not all of them and maybe they started because of the drying and I did not notice. So I will try again some day.
I work as a retinal surgeon but wanted to be a potter in high school and worked in South Pasadena with my teacher Rollie Younger for a few years in a studio we put together. Now I am starting to think about  the end of working and want to get good if that is possible. There are so many variables with this stuff that I am going very slow---titanium really changes the results and is not talked about very much. I have really enjoyed looking at your work---it is saving me time.  Thanks  Kirk

I worked on jars for a time and found the variables of size of the lid for the jar drove me nuts. Then there is the knob or handle. They crack along the brim of the top where you push the bowl out to size the lid. So I stopped making them. I'll put a photo.  Kirk


Franklinite Link


Info from Kirk

-You need manganese activated willemite for it to fluoresce.

-Franklin Museum....Earl....Curator

-Short wave UV Light....UV Systems.....Don

    ~$400 - Super Bright

    ~$900 Triple Bright

-Florescent article...John Singer...Clay Times 2005

        "Fluorescent Glazes" (Jon Singer), 2005 May/Jun:48-52

-Book....Crystalline Glazes....Donald Holloway.....Louisiana

        THE ART AND CRAFT OF CRYSTALS, Donald R. Holloway.



I sent the following via UPS today:

Piece # 27 Small pot containing 2% Manganese Dioxide
Piece # 29 Small pot containing 4% Manganese Dioxide
Piece # 36 Small pot containing ~ .18% cobalt carbonate and 1% copper carbonate. I know you said cobalt is death, but this piece developed a haze I have not seen before and I thought maybe.....just maybe....
Piece # 64 Test piece containing 0.5% Strontium Carbonate, 0.2% Green Nickel4.5% Black Iron and 1.0% Manganese.. (Another maybe.....maybe).
Piece # 79 Test piece containing 1/4% CoCO3+ 1% MnO2 after 900C heat treatment. (Another maybe.....maybe. Again I know you said cobalt is death, but this piece developed the nice robin's egg blue in the background after heat treatment).



The green is 5% black copper, 1 tit,2bent, snair #2base  The blue on gray is 1/4 co, 2 Mn, 1 tit, 2 bent, same base.







Molybdenum Crystalline Glazes

  Little is written about molybdenum as a glaze material. Our limited research has turned up a bit of information. It was discovered in the latter part of the 18th century by a Swedish scientist, Carl Wilhelm Scheele. We are unsure who brought the technical use of molybdenum in glazes to the U.S. from Europe. We do start seeing its use during the Arts and Crafts pottery period made during the turn of the twentieth century. The potters of whom we are aware who experimented with molybdenum crystalline glazes are Adelaide Robineau, Charles Fergus Binns, Frederick H. Rhead, Otto and Gertrude Natzler, and Herbert Sanders.
   An excerpt by Phyllis Ihrman, from Peggy Weiss book about Adelaide Alsop Robineau gives a good description, The molybdenum crystal is very elusive, less predictable, and more difficult to achieve than most other types of crystal. It differs from the zinc silicate and titanium crystal in that it is usually quite small and shaped like a rectangle, star, or diamond. In multitude they are double refracting, separating light into different colored rays. They seem to float on the surface of the glaze and display all the iridescent colors of the rainbow as light plays over them. The matrix is usually very lustrous and opaque. Often the crystals are very subtle only being seen when the pot is tipped to catch the light.(1)

(1) Weiss, Peg, Adelaide Alsop Robineau Glory in Porcelain, Syracuse University Press, New York, 1981, page 150


> I would like to expound upon what Terry and Fara have said, and what might be confusing about it.
> Terry is talking about adding moly to a typical recipe. Supposedly, doing this yields a pale yellow, but for me, it is so weak that it can be seen, except for sometimes in the halos. But moly added this way has a significant effect on the shape of the crystals. It makes them more complicated and/or frillier. You might like it, or not, it a personal taste thing. In conjunction with other colorants, it makes them whiter, meaning pastel-like.
> The moly crystals that Fa is talking about, which are explained in the Sanders book, are a completely different animal from zinc-silicate macro-crystalline glazes.
> Here a link:
> http://www.bulldogpottery.com/Mo%20description.htm
> Fa mentions growing moly crystals in a tight kiln. I have been told that the moly becomes a vapor, and the crystals don actually form until the kiln is shut off and cooling, and the moly re-attaches to the glaze. My thought has been that the best way to make moly crystals would be in a sagger.
> William Melstrom

Thank you for the help on this. I am still unsure what percentage to use in a zinc-silicate glaze. If I want more color should I try 4%. Terry indicated max 5%. What would you suggest as a first try. I have 4% Titanium in the glaze (if this matters).
Sounds like it does not work well with colorants. So I think I will try it alone.

5% max.
2% nice
less than 2% not much change
2% no colorant, nice white crystals
strange results when I used iron
nice with 1.5% nickel
I use very low Tio2 in my glazes.



I've had great success with Moly, using the glazes in Sanders' book. 4% of the oxide or 5% of the sulfate is usually enough, but keep your kiln tightly closed when you fire. The only colorants I've tried are iron and cobalt; cobalt is okay, iron combines with the moly and while what you get is very interesting, it's not what I'd call pretty.

Fara Shimbo