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mrs_christopher

Help me, Glaze gurus!

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I was very fortunate enough to have one of my favorite potters give me a small insight to how they glaze their pieces, but the only tip they left me with glaze wise was that they used a very "runny" or "melty" glaze. This potter also will mix mason stains into that glaze from time to time. I have been reading up about raw materials, and frits, because I noticed it's a common material used in clear coats to get the "melt" factor of the glaze. (Please correct me if I'm horribly wrong)

 

Anyways, would anyone out there happen to have a good "melty" clear base glaze recipe that mason stains can easily be mixed into? This is a guess, but I'm probably looking for one that doesn't have too many materials that work as suspenders in the glaze. I am planning on adding cmc gum to this base glaze to make it partially brushable.

 

I'm a total newbie to this whole "mix your own glaze" thing, so explanations are amazing for the newer people like myself!! :) I seriously gave myself a headache one day trying to calculate mixing glaze in a 5 gal bucket, but that is a WHOLE other story!! LOL!!

 

I'd be happy to send you pieces of the potters work in private if you have questions about the look, but I didn't want to tarnish, or spill the beans publicly in case they enjoy reading these boards as much as I do! :)

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Guest JBaymore

The piece of missing information we need is the end point firing cone that you want to work with. Without that.... can't answer at all.

 

best,

 

.............john

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The piece of missing information we need is the end point firing cone that you want to work with. Without that.... can't answer at all.

 

best,

 

.............john

 

 

Ooops!! I guess that is really important!! I'm looking for something to fire on porcelain, so probably anything between ^03-^6.

 

Thanks ahead!!!

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I think you should have a look at the porcelain body you're using and what its parameters are in the firing range. Talk to your supplier for starters. You mention ^6 but seem a bit vague about firing range. Usually a "true" porcelain needs to vitrify at a quite high temperature. But there are bodies which maintain some porcelain qualities (whiteness and a surface vitrification of sorts) and fire in the ^04-^6 range. You won't achieve seductive translucency at ^6, but it's a start. So, given your level of experience and interest in making your own glazes have a look at Mastering ^6 Glazes by Ron Roy and John Hesselberth. Another excellent reference is Michael Bailey's Glazes ^6. These books will provide you with wonderful recipes and exciting jumping off points for further testing. I must emphasize that a porcelain body will afford you quite different results from let's say a body which has a bit of iron in it, or some manganese flecks firing at ^6. Protect your shelving and wipe glaze tests on a porcelain body quite high up! Read these two books through several times to catch the nuances and inferences as to which body they've described using under their cited glazes. Also, follow the recommended firing schedules, and check the websites proferred for updated versions of preferred firing shedules, especially via John Hessleberth's website. You'll do well to develop a separate suite of glazes for a "fast" downfiring and then another one for a slower which will help you develop lovely crystallization and variety within a glaze. And don't forget to combine glazes using blending and overlapping which is exquisite and intriguing. Using fine tipped slip trailers to make inglaze decoration also provides a huge scope for decorative techniques, as does hot wax. Enjoy! Use self-supporting Orton Cones to determine heat work on at least the bottom and top levels of kiln, keep a yearly Studio Journal and keep a Kiln Log -- makes selling on any kiln easier because you can state hand on heart that you never fired the kiln up to ^10. Ever. Faithfully. Make notes about your firing results so you don't duplicate silly mistakes.

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Here is a ^6 clear that I am currently using:

 

So Clear (^6 Oxidation)

 

Frit 3124, 32.2%

Kona F4 Feldspar (Soda Spar), 25.8%

Silica, 19.4%

Whiting, 12.9%

EPK, 9.6%

 

The recipe is one that Michael Sherrill handed out at a workshop; he stated that he adds stains to it.

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Guest JBaymore

Ooops!! I guess that is really important!! I'm looking for something to fire on porcelain, so probably anything between ^03-^6.

 

As has already been mentioned, if you truly mean porcelain, in the truest sense of the word, then the firing range is typically something like Orton cone 8 to 12. Procelain is a high fire clay body.

 

There are also white clay bodies readily available that fire in the range of Orton cone 04-06, and then there are mid-range white "pseudo-porcelains" that mature in the Orton cone 5-6 range. So is a white clay the goal, or actually the use of porcelain?

 

The range you mentioon... cone 03 to 6........ is a HUGE spread of effective heat work (what cones actually measure...... applied heat energy over time). A glaze formula/recipe that works for cone 03 will not be appropriate for cone 6, and vice versa.

 

SO first off, you really need to really figure out/ understand to what cone you will actually be firing. The goal is to have the glaze match the maturity or end firing point of the clay body that will underlie it. So check the matuiring point of your clay body, and also the capabilities of your kiln to decide on this situation.

 

You mention both the terrms "clear" and "runny" in your glaze description. "Clear" is easy to understand, but why did you specifically mention "runny"? Is there a visual characteristic that shows that the glaze you desire is "moving" a lot during the firing? Like showing little rivulets within the glaze surface? Or maybe the glaze shows that it has actual drips coming down on places that have been left unglazed and the drips are deliberately allowed to go there?

 

Was the potter whose work you looked at firing to the came cone range that you plan to fire?

 

You can mix Mason stains into any clear base glaze )or even ionto non-clear glazes) and get color rendition. Sometimes the chemistry of the base glaze is important, because some such colors react to the base glaze chemistry, but a lot of the stains are "stabilized" to a point that the base glaze chemistry is pretty unimportant. Some colors have termoperature ranges above which the color rendition changes or even basically ceases to work. Reds, oranges, and yellows are typically the most problematic in this regard.

 

best,

 

....................john

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I'm currently using a slip casting method for my work using Columbus Clay's porcelain slip. ^4-^6 (I personally fire to ^5, because I think my kiln fires a bit too hot, which causes the porcelain to sometimes get caught on the shelves)

 

http://columbusclay.com/Slip.htm

 

 

The reason I mentioned the lower fire range was because I tend to glaze my pieces at a lower range than what I bisque them, but I now just realized that I would be doing a "One time firing" after applying the glazes on to green ware. (<--- maybe... if it'll work) I have no clue what the potter in question fires their pieces to, but I'm guessing since they slip cast, then it can't be too terribly high for fear of the thin walls melting, or slumping.

 

I've attached a picture of a couple of Ayumi Horie's pieces that use a very similar effect to what I'm looking for, so you can understand when I say "melty" or "runny". Just add more colors in the the mix.

 

The potter I am looking at said they pile on their stained glaze very thick, which causes it to run, and that they use a very "melty" clear base then add mason stains to it.

 

I have NO idea what the potter fires to. I think that was one thing they wanted didn't want to let out, so I'm giving my firing ranges in hope someone can figure out, or know of a base glaze that could work in my situation.

 

I hope this helps a little bit more.

post-6532-131929345804_thumb.jpg

post-6532-131929345804_thumb.jpg

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Guest JBaymore

Here is a ^6 clear that I am currently using:

 

So Clear (^6 Oxidation)

 

Frit 3124, 32.2%

Kona F4 Feldspar (Soda Spar), 25.8%

Silica, 19.4%

Whiting, 12.9%

EPK, 9.6%

 

The recipe is one that Michael Sherrill handed out at a workshop; he stated that he adds stains to it.

 

 

Since you seem to be firing to cone 6 (your "hot" cone 5), bciskepottery gave you a clear recipe to try out already (above).

 

For more, look up cone 6 clear glazes in ceramic glaze texts or online and then test, test, test.

 

Note that this glaze is not suitable for once firing. Adding in that particular problem complicates things greatly. I'd say first, just find a clear that works for you.

 

 

best,

 

...................john

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Here is a ^6 clear that I am currently using:

 

So Clear (^6 Oxidation)

 

Frit 3124, 32.2%

Kona F4 Feldspar (Soda Spar), 25.8%

Silica, 19.4%

Whiting, 12.9%

EPK, 9.6%

 

The recipe is one that Michael Sherrill handed out at a workshop; he stated that he adds stains to it.

 

 

Just curious... in your experience does this clear work with most clays and over other glazes, or are there some know "sensitivities" (eg, color changes, crazing on certain clays, other glaze interactions, etc.). Certainly I'd test for my particulars, but I don't have soda spar on hand and there's no use purchasing some if there are known limitations which I might not want to accommodate... the last thing I need is another bucket of once used chemical. Like most clears, I assume a thin application gives best results?

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I use this clear mostly on Highwater's Little Loafers and Highwater's Buncombe White, both ^6 white clay bodies. On ^6 bodies, I've not noticed any crazing. Covers underglazes well; seems to interact with other glazes okay -- I mostly use Mastering Cone 6 glazes. A thin coat works fine; seems forgiving if you have runs or drips and holds well to wax lines.

 

Our studio previously used a MC6 clear, but that had a tendency to yellow; this one seems to be pretty clear on whites. I've gotten some distortion on browns and reds.

 

I did try it on Highwater's Loafers Glory, a ^7-10 clay body but fired at ^6 and did have some crazing.

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Here is a ^6 clear that I am currently using:

 

So Clear (^6 Oxidation)

 

Frit 3124, 32.2%

Kona F4 Feldspar (Soda Spar), 25.8%

Silica, 19.4%

Whiting, 12.9%

EPK, 9.6%

 

The recipe is one that Michael Sherrill handed out at a workshop; he stated that he adds stains to it.

 

 

Since you seem to be firing to cone 6 (your "hot" cone 5), bciskepottery gave you a clear recipe to try out already (above).

 

For more, look up cone 6 clear glazes in ceramic glaze texts or online and then test, test, test.

 

Note that this glaze is not suitable for once firing. Adding in that particular problem complicates things greatly. I'd say first, just find a clear that works for you.

 

 

best,

 

...................john

 

 

 

 

Thanks for the help, guys! I will test and see what I can find out.

 

So far all my commercial test glazing hasn't given my the results I wanted, so maybe this'll do the trick!!

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ACTUALLY, I DO have one more question...

 

Is it possible that if I swapped the Frit3124 for Frit 3195, do you think I would get more of a runny effect, or just more of a mess?

 

I'm trying to decipher the differences between the two raw materials, and what the outcome might be. Digital fire described the frit 3195 as "fluid".

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I have looked at your example images and here is one point that might help you ...

 

I believe Ayumi's runny-ness comes from the underglaze color reacting with the clear overglaze and bleeding into it. Potters who wanted crisp clear lines would throw their hands in the air and call it a failure ... but she celebrates the effect and manipulates it in her decoration. I bet she even tweeks her glazes to react more with the underglaze decoration.

 

In my experience I have found that commercial glazes have been 'improved' to the point they don't do this because not many potters want it to happen ... so you would need to make your own. The most bleeding with color mason stains that I have noticed in my own work occurs when there is Gerstley Borate in the clear glaze. Now using Gerstley also has the effect of changing some colors so it is not a clear cut choice and your results may vary from mine.

 

My best suggestion for you is to make some glaze tile samples and experiment ... these tiles are often an italic "L" shape with a pattern somewhere on it so you can see how the glaze pools and breaks.

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I have looked at your example images and here is one point that might help you ...

 

I believe Ayumi's runny-ness comes from the underglaze color reacting with the clear overglaze and bleeding into it. Potters who wanted crisp clear lines would throw their hands in the air and call it a failure ... but she celebrates the effect and manipulates it in her decoration. I bet she even tweeks her glazes to react more with the underglaze decoration.

 

In my experience I have found that commercial glazes have been 'improved' to the point they don't do this because not many potters want it to happen ... so you would need to make your own. The most bleeding with color mason stains that I have noticed in my own work occurs when there is Gerstley Borate in the clear glaze. Now using Gerstley also has the effect of changing some colors so it is not a clear cut choice and your results may vary from mine.

 

My best suggestion for you is to make some glaze tile samples and experiment ... these tiles are often an italic "L" shape with a pattern somewhere on it so you can see how the glaze pools and breaks.

 

 

Thank you, Chris! That was extremely helpful!!!

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I use this clear mostly on Highwater's Little Loafers and Highwater's Buncombe White, both ^6 white clay bodies. On ^6 bodies, I've not noticed any crazing. Covers underglazes well; seems to interact with other glazes okay -- I mostly use Mastering Cone 6 glazes. A thin coat works fine; seems forgiving if you have runs or drips and holds well to wax lines.

 

Our studio previously used a MC6 clear, but that had a tendency to yellow; this one seems to be pretty clear on whites. I've gotten some distortion on browns and reds.

 

I did try it on Highwater's Loafers Glory, a ^7-10 clay body but fired at ^6 and did have some crazing.

 

 

Thanks Bruce... just the info I was looking for. We use a wide variety of Laguna clays.... dark & med browns, reds, and whites fired to ^5. Sounds like it's worth picking up a pound of soda spar for a test batch the next time I buy chemicals.

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I have looked at your example images and here is one point that might help you ...

 

I believe Ayumi's runny-ness comes from the underglaze color reacting with the clear overglaze and bleeding into it. Potters who wanted crisp clear lines would throw their hands in the air and call it a failure ... but she celebrates the effect and manipulates it in her decoration. I bet she even tweeks her glazes to react more with the underglaze decoration.

 

In my experience I have found that commercial glazes have been 'improved' to the point they don't do this because not many potters want it to happen ... so you would need to make your own. The most bleeding with color mason stains that I have noticed in my own work occurs when there is Gerstley Borate in the clear glaze. Now using Gerstley also has the effect of changing some colors so it is not a clear cut choice and your results may vary from mine.

 

My best suggestion for you is to make some glaze tile samples and experiment ... these tiles are often an italic "L" shape with a pattern somewhere on it so you can see how the glaze pools and breaks.

 

 

Thank you, Chris! That was extremely helpful!!!

 

 

 

You could also try adding a flux to your oxide stain (or mason stain) to make it bleed . . . that could isolate the runniness to only where you put the stain and allow the rest of the clear to remain more stable.

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I have looked at your example images and here is one point that might help you ...

 

I believe Ayumi's runny-ness comes from the underglaze color reacting with the clear overglaze and bleeding into it. Potters who wanted crisp clear lines would throw their hands in the air and call it a failure ... but she celebrates the effect and manipulates it in her decoration. I bet she even tweeks her glazes to react more with the underglaze decoration.

 

In my experience I have found that commercial glazes have been 'improved' to the point they don't do this because not many potters want it to happen ... so you would need to make your own. The most bleeding with color mason stains that I have noticed in my own work occurs when there is Gerstley Borate in the clear glaze. Now using Gerstley also has the effect of changing some colors so it is not a clear cut choice and your results may vary from mine.

 

My best suggestion for you is to make some glaze tile samples and experiment ... these tiles are often an italic "L" shape with a pattern somewhere on it so you can see how the glaze pools and breaks.

 

 

Thank you, Chris! That was extremely helpful!!!

 

 

 

You could also try adding a flux to your oxide stain (or mason stain) to make it bleed . . . that could isolate the runniness to only where you put the stain and allow the rest of the clear to remain more stable.

 

 

Another awesome idea. Thanks!!

What flux would you recommend?

 

How should I mix it up with the stain? Should I a little water to it?

 

My only down thought would be, would a very "stay put" clear coat prevent the runny-ness underneath?

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I'm currently using a slip casting method for my work using Columbus Clay's porcelain slip. ^4-^6 (I personally fire to ^5, because I think my kiln fires a bit too hot, which causes the porcelain to sometimes get caught on the shelves)

 

http://columbusclay.com/Slip.htm

 

 

The reason I mentioned the lower fire range was because I tend to glaze my pieces at a lower range than what I bisque them, but I now just realized that I would be doing a "One time firing" after applying the glazes on to green ware. (<--- maybe... if it'll work) I have no clue what the potter in question fires their pieces to, but I'm guessing since they slip cast, then it can't be too terribly high for fear of the thin walls melting, or slumping.

 

I've attached a picture of a couple of Ayumi Horie's pieces that use a very similar effect to what I'm looking for, so you can understand when I say "melty" or "runny". Just add more colors in the the mix.

 

The potter I am looking at said they pile on their stained glaze very thick, which causes it to run, and that they use a very "melty" clear base then add mason stains to it.

 

I have NO idea what the potter fires to. I think that was one thing they wanted didn't want to let out, so I'm giving my firing ranges in hope someone can figure out, or know of a base glaze that could work in my situation.

 

I hope this helps a little bit more.

 

If you are doing One firing i.e. glazing greenware, add 5% bentonite to the recipe. This will adjust it for shrinkage and fitting the greenware.

Marcia

 

 

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Another possibility to get that kind of effect isin the application, instead of during the firing process or a mixture of thetwo. If you avoid adding too much bonding agent(cmc/bentonite/GB/ball clay) to the stain/slip, it stays powdery and spreads/bleedswhile the glaze is being applied with a brush or the piece dipped in the glaze…You need to play around with the stain/slip application, and the amount offlux, to get it right.

 

Things that might work as flux: Low fire clear, frit 3110, 3134, GB

 

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Don't know if you have all the info you can use at one time yet, but here is a recipe given to me by a friend.

I love it because it is so easy, and I get such nice results from it. I use it on ^5-6 clay.

 

10 EPK

21 Gertsley Borate

30 Nepheline Syenite

8 Wollastonite

31 Flint

100 grams

 

As for the colorants, I usually use about 6-7% Mason Stains

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Don't know if you have all the info you can use at one time yet, but here is a recipe given to me by a friend.

I love it because it is so easy, and I get such nice results from it. I use it on ^5-6 clay.

 

10 EPK

21 Gertsley Borate

30 Nepheline Syenite

8 Wollastonite

31 Flint

100 grams

 

As for the colorants, I usually use about 6-7% Mason Stains

 

 

Thank-you! That sounds like a great base glaze, and my supplier carries all of those raw materials too! :)

 

Thanks for sharing!

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I find that glazing items and becoming an expert at it is something that comes with experience and experimenting. Try combinations of chemicals, pieces of glass, and other things you make your paint stand out and look great! It is also that you have some great items to paint. My favorite items are deco art bisque items. Very interesting designs these pieces.

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