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Comment by Norm Stuart on October 25, 2015 at 9:00pm

Brenda - Randy McCall's Warm Jade is a winner, shown slow-cooled and without slow-cool. One of the most popular glaze at our studio, and it does very interesting things layered as a base coat with another glaze over the top, like the Clear Blue which is the subject of this topic.

Send a message to George Lewter at this link to join the Insight-Live Users Group which has this and 750 additional glaze recipes. - http://cone6pots.ning.com/groups/group/show?groupUrl=insight-live-u...

When using the Insight-Live database you can click on these thumbnail photos to open full-sized photos of each glaze.

Comment by Brenda B Hardt on October 25, 2015 at 8:37pm

Hello.  In a related post there is mention of WARM JADE.  Very lovely glaze.

Could some please post the recipe for that one?  Is it slow cool too?  Thank you in advance.  I am jsut 3 months into trying to make my own glazes... not an easy journey.  Thanks so much.

From a Texas new to this potter. 

Comment by Norm Stuart on April 23, 2013 at 12:28am

I think we're slow-cooling in the 1,800F to 1,500F twice as slow as you are. One of the problems some glazes develop with cooling this slow is over-crystallization.

I think the only ingredient in this glaze that sometimes sparks crystallization is rutile, which is why this glaze works so well with slow-cooling. Granular Ilmenite really sparks crystallization, especially in iron glazes, which this isn't.

Trying to create crystallization is the opposite of what I'm usually faced with. What would I add to make it crystallize? Zinc oxide would work but it will probably change the look of the glaze. I sometimes add 5% or so of tin oxide to matte out the shine in a glaze and make it look smoother and richer, while titanium usually just adds whitening. The wollastonite version is already more opaque due to the calcium semi-matte aspect it adds. But I making the glaze more clear with the Minspar or Kona Feldspar is what makes the glaze look so much better in person.

The crystallization caused by very slow-cooling can draw the glass down below the top of the crystals leaving an ugly matte glaze. So I add 10% or so of a frit like 3401 or 3269. Here are a couple of examples.

This is Gold Brown Transparent - BG1 C/6 

http://www.wpapotters.blogspot.com/2010/11/cone-6-oxidation-results...

At our slow-cool the glaze yellow crystals show only where the glaze is thickest, there's too little glass and the glaze is brown rather than gold.

I added 10% more Minspar and 10% Ferro Frit 3269 produces the glaze on the right which is closer in concept to the original glaze. One ingredient which made this glaze over-crytallized at very slow cool is the 5% Zinc Oxide.

This Sapphire glaze at different cooling rates shows how the glaze ends up needing more silica and flux to maintain the look.

McCalls Great Grey needed just 10% Minspar to give the glaze the correct flow on the right, but it still looks quite different to the original.

http://mccallsc.tripod.com/pottery-glaze-testing.html

Comment by Jeff Poulter on April 22, 2013 at 8:27pm

I really like this blue. I will have to mix some up. If you wanted to make it variegate more with areas of matt crystallization, what could we add? Jeff

Comment by Norm Stuart on April 22, 2013 at 7:34pm

Variations of Clear Blue at ^6 with 50 degree F per hour cooling between 1,800 and 1,500.

The original Clear Blue with Wollastonite, nice but a stiff glaze which crawls.

On the left below is the same glaze with Wollastonite replaced with Minspar on the left but on a different clay than the original,

On the right below is the Ron Roy revised recipe on the right so it doesn't bust pots - but almost the same look.

Three coats on top, two in the middle, and one on the bottom.

Comment by Randy McCall on April 14, 2013 at 1:22pm

Post a picture of it as I will try it but it may be a month or so before I get anything fired.

 

 

Comment by Norm Stuart on April 14, 2013 at 11:25am

I'll try the revised formula out today, but it won't be fired until next week.

Comment by Randy McCall on April 14, 2013 at 11:12am

I checked on clayart about the durability of this glaze.  Ron Roy said that it may cause shivering on some clays and be a pot buster.  He revised the glaze for durability and fit.  Here is the result of his suggestion.

 

Recipe Name:  Blue Clear

Cone:  6     Color:  Bright Blue Firing:       Surface:  Glossy

Amount     Ingredient

29          Frit--Ferro 3134

23          Feldspar--Kona F4

6          Talc

28          Kaolin--EPK

14          Silica

100         Total

               Additives 1.5          Cobalt Carbonate .5          Rutile

Unity          Oxide .293           Na2O .051           K2O .18           MgO .476           CaO 1.000          Total

.582           Al2O3 .38           B2O3 .005           Fe2O3

3.881           SiO2 .004           TiO2 .001           P2O5

6.7          Ratio 68            Exp

Comments:  ----------------------------------- Calculations by GlazeMaster™ www.masteringglazes.com ------------------------------------

Comment by Norm Stuart on April 14, 2013 at 11:06am

Thank you both. When I started making glazes two years ago I was greatly assisted by your website Randy.

http://mccallsc.tripod.com/pottery-glaze-testing.html

This is how your "Warm Jade" glaze comes out on white clay with our ^6 firing with 50F slow-cooling between 1,800F and 1,500F - it's one of the most popular glazes at our studio. My tiles are three coats on top, two in the middle and one at the bottom.

Comment by Robert Serva on April 14, 2013 at 7:13am

Thank you for your efforts, it is research like this that helps us all in the glaze jungle.  Great work!! I am just starting to work on mixing my own glazes and this helps with good direction.

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