Cone 6 Glazes WITHOUT Gertsley Borate?

Just curious how people are doing on coming up with glazes without Gertsley Borate. Does anyone have a favorite out of the "Mastering Cone 6 Glazes" book? All of the glazes we use in the studio I have worked in are based on the various Gertsley formulas. The glazes I like are the Randy's Red, Honey, and the copper glazes that can't be used on the inside of pots (Pennels with Erins green)...

I have just bought an electric kiln and have "Mastering Cone 6 Glazes" . I was schooled in reduction ^8-10 and am more than a tad nervous about the whole endeavor of oxidation firings at cone 6. To me even the Gertsley Borate glazes often look flat with oxidation ^6. My favorite glazes that I learned on were Albany slip with rutile oxide decorations, the iron based celadon when it went blue sea green, and Shino. I do not want to carry on the error of using GB. I'm working in a very small space and don't really want to buy more that a half dozen bags of ingredients. In any case I can't seem to kick start myself into beginning. I find that even though I used to make up our glazes for reduction firings that I don't know what silica to use for the base glazes out of MC6G... We never used silica as the ingredient "Silica" and my catalogs don't have anything listed in that form that appears to be a glaze ingredient. Now I have given much more information that anyone cares to read or is interested in..... Mostly I'm looking for some kind of nudge to get me in gear.

Reply to
dkat
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Hi dkat, I have started playing with cone six glazes by adjusting my favourite cone

10 glazes... however, I was always firing oxidation, so it was a bit easier. Anyway, If you add 10% frit 4108 ( used to substitute gerstley borate) to cone 10 glazes, you are likely to get simmilar glaze maturing at cone
Reply to
A&V

Hi dkat,

That's how I started. Frustrated with the firing results at school, I bought an electric kiln and "MC6G". Before that I had never mixed glazes or fired a kiln. It took alot of work and alot of trial and error but I have finally started seeing it pay off. Since you already have experience in glazes and firing, I am sure that you won't have the amount of issues to overcome that I did. Check out my site for some results and let me know what you think. Just keep in mind I have only been potting for about a year and a half.

Bert Gibson

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Bert Gibson

Reply to
dkat

It is not becoming for a woman of my age to feel .... well ... green with envy and jealousy.... Those are really lovely and it is really impossible to believe that you have just been doing this a year plus.

The reduction pieces brought back many memories.

Thank you.

Reply to
dkat

Most cone 6 gerstley recipes, if the content is not too large, can be adjusted for frits. Ferro frits 3124,3134 and 3195 are all boron bearing frits. As far as glazes go you have to decide what kind of work you want to produce and what surface and colors you think would be appropriate for that work. You can use ash or fake ash glazes for one look, transparent glossy glazes that can be used alone of over slips for more depth and variation is another way to go, or matt glazes or all of the above. Oxidation glazes can have depth by layering, using slips underneath, etc. Any or all of the above can give you a good body of work. You just have to put in the time and start testing. I just finished spending several days batching glaze tests and now have over 60 tiles that I'm getting ready for firing. You just have to be willing to put in the hard time. You are the only one who can give yourself the jump start. The web is filled with glaze recipes, pictures of glazes and pots, etc. One good base glaze can give you an unlimited number of colors to choose from. Make sketches of the pots you want to make and then decide what claybody you want to use and what kind of glaze you would want to see on those forms and start testing. As far as silica, I use 200 mesh just because I feel it's a bit safer than dealing with finer, air born, silica particles of 400 mesh. The finer mesh will melt sooner and often it is used because if a glaze is borderline crazing the finer silica or amorphous silica can sometimes prevent that. I'd rather alter the expansion of the glaze in most cases rather than resorting to using finer silica. Lastly, I think it's a mistake to think you have to make oxidation glazes look like cone 10 reduction glazes. There is some wonderful work coming out of cone

6 oxidation and I just think it's waste of energy to try to make it something it isn't. At best you can only expect a poor substitute for the most part. You can get beautiful matts at cone 6 with firing down, which permits crystal growth. With cone 6 oxidation you have a vast color pallette to work with and with some creative endeavors can get interesting looking work. Maybe incoroporate more texture in your pieces and then those transparent glazes will pool beautifully, giving them more depth and interest. You just have to get in there and start working. If you're using Randy's red you might want to test it since with all that gerstley and high iron it might leach and may not do well over time in the dishwasher. It's a glaze that may best be saved for non functional work that won't be subjected to the harsh environment of the chemicals in a dishwasher. You can do a quick vinegar test by putting some vinegar in part of a shallow dish with this glaze and let it sit a couple of days and see if it changes color. It's not a definitive test if it doesn't; but if it does, it shows you that it is leaching and won't be food safe or dishwasher safe.

Regards, June Perry

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Reply to
ShantiP1

Bert, Just had a look at your site. Love the "Sky Blue" any chance of you sharing the recipe with us all. Kind Regards

Kevin.

Reply to
Kevin Baldwin

Hi Kevin, Sorry, if it were my glaze I would share, but it's not. It belong's to John Hesselberth and Ron Roy. They asked that the recipes not be given out because they published the book at thier own expense. They have a website (masteringglazes.com) through which you can get it. Well worth the cost and they have been more than generous when answering my questions. Also, "your mileage may very" as they say. Though I followed thier formula and thier firing schedule, my results were different then they showed in the book.

Regards, Bert Gibson

Kev> Bert,

Reply to
Bert Gibson

I might add that it is a very nice book and well worth having.

Reply to
dkat

If you were to live across the Atlantic in the UK, for example, you would never have bothered with Gertsley Borate in the first place.

If you want cone 6 glazes without this material than you will find plenty of recipes in Mike Bailey's book 'Glazes Cone 6', some without either Gertsley Borate or a fritt.

ISBN 0-8122-1782-9

David In article , dkat writes

Reply to
David Hewitt

You are getting some very nice results with those cone 6 glazes. I especially like the waterfall brown over licorice, and bright blue over licorice. You might try the licorice over the bone as an experiment. Excellent work for only a year and a half, and even for 4 to 5 years. I don't remember making anything decent looking for quite a few years.

Reply to
Brad Panek

Thanks Brad. I will be glad when my throwing skills match my glazing results.:) You know in a picture you can't tell how small or heavy the pot actually is. At least the confidence in my glazing and firing helps keep me motivated when I start getting frustated at the wheel.

My last firing I tried that combination. I got a very dark green color. The licorice wasn't applied thick enough to give much flow down the sides of the bowl, but the results were enough to make me want to try it again.

Bert Gibs> You are getting some very nice results with those cone 6 glazes. I

Reply to
Bert Gibson

I set up a page with my test tiles from "Mastering Cone 6 Glazes". These were done a year or so ago. This was a "hot"cone 6 firing and I was learning about mixing and applying glazes so they are not the best results. Three different clays were used: white, buff, and a dark in that order as you look at the screen.

Bert Gibson

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Reply to
Bert Gibson

I think your purple is very attractive - a nice modification of the raspberry.

- Kobey

Bert Gibs> Hi dkat,

Reply to
Kobey

Dear Bert,

You were wise to test on different bodies and your site is a very good one; and particularly good to direct people to who are just starting out on glazing and could benefit from seeing the variations in the different clay bodies, as well as your combinations. I tested the spearmint and mine came out looking a lot like yours and nothing like the book, where it looks like a soft, lovely green. My test was done on a white stoneware. I don't like the green, as it turned out, but liked it as it is shown in the book. I should ask Ron if that picture is representative of the fired result. At times, with certain glazes, I have tested them on 3 or 4 bodies (particular transparent glazes, chuns,etc.) and the color was different on each one. Even porcelain and white stoneware can give quite different results. Viewing your tests one can clearly see why the old adage "Glazes don't travel well" applies. People often don't realize that the claybody selection can make a vast difference in the color of the glaze, as well as other factors, i.e. the water used, firing time, firing conditions, raw materials used,etc.. You're doing very, very well for someone only throwing a year and a half! You either had a great teacher or practiced a lot or have done this in a past life or one or more of the above! LOL

Warmest regards, June

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Reply to
ShantiP1

Their FAQ page on MC6G states

" 6. I am having trouble with glazes like Bone and Spearmint turning out a yucky yellowish and yellowish-green respectively. Any ideas? Yes. Several people have had this problem. In every case so far we have traced it to rutile that is different from ours or, in the case of Spearmint, to using a non-white clay body. Try replacing the 6% rutile with about 5% titanium dioxide (rutile is an ore from whiich TiO2 is extracted) and your colors will probably be closer to ours. "

but the book seems to suggest that it is more an issue of rate of cooling in this case (time necessary for the crystals to form to give a matt finish). It very much looks like the difference in the slate blue example under firing rate

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like how the green on Bert's page looks as well as the one in MC6G (thatis - I like them both).

Reply to
dkat

I tested it on a white stoneware and used ceramic grade rutile. When I get time I'll make another test with light rutile. I also fired down, so it wasn't the firing or the claybody.

Regards, June

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Reply to
ShantiP1

Reply to
D Kat

I think she means she controlled the rate of cooling. The key to success with John and Ron's glazes is slow cooling. From 1900F down to 1500F they suggest a temperature drop of about 125 degrees per hour.

Bert Gibson

D Kat wrote:

Reply to
Bert Gibson

Hey Wayne,

If you check out John's slide show from the conference he show's his current firing schedule. It's different than on the website for the book.

I must have missed the element thread, thanks for alerting me, I'll go check it out.

Bert Gibs>> I think she means she controlled the rate of cooling. The key to

Reply to
Bert Gibson

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