[Clayart] Using frit as a substitute

[Rick Mahaffey via Clayart]

You may find a frit the substitute for various materials but remember frit is ground glass so it settles out and tends to pack in the glaze bucket so you may have to adjust the portion of clay I your recipe. Changing some of the kaolin to ball clay may help keep the frit in Suspension longer. If you are already using ball clay then switching some to bentonite might be necessary.

Remember when you substitute materials you have changed the glaze. To quote my graduate advisor “It may be similar but it won’t be the same”.

Your mileage may vary,

Rick
Sent from my iPad

[ronroy--- via Clayart]

Hi Rick,

Just to add to your thoughts,

Best to use a frit that has no alumina or very little so you can add
more clay to the glaze to help suspension.

Unless you need a very white glaze it’s best to use ball clay instead
of kaolin. Ball clay is a better suspender and has less alumina so yo
can get more in the glaze.

Anyone who wants my glaze course book just let me know and I can send
a PDF file. It has a lot of analysis in it.

RR

Ron Roy
ron...@ca.inter.net
Web page ronroy.net

[David Woof via Clayart]

Hi Ron,
You and I agree on, let's say, 99% of what we both have said as advice over these many years. But please state why you seemingly resist offering using deflocculation of the glaze slop to complete the solution for problems of inadequate suspension.

Yes, one must include adequate Clay and Bentonite, but why the resistance to further advising adding a deflocculant as well?

Tell us please.....

Misneach,

David Woof.....................................................................................................................................................................................
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From: Clayart <clayart...@lists.clayartforum.com> on behalf of ronroy--- via Clayart <cla...@lists.clayartforum.com>
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Subject: Re: [Clayart] Using frit as a substitute

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[ronroy--- via Clayart]

Hi David,

I have never done that and you are the only one I know of that does it.

I do know that over defloccing has the opposite effect (flocculation)
but it means adding more chemicals.

Perhaps you should say exactly how you do it and what advantages you
find in it.

Are there any descriptions in any books that recommend it?

I'm not saying it does not work but I have always thought that
formulating a glaze that does not need flocculating is the better
solution.

How do you deal with the extra solubles - are there ever problems? I
know that solubles travel as glazes dry and even can affect the clay
and glaze.

Happy to discuss this David, There is no downside to added understanding!

RR

[Paul Randall via Clayart]

David, Ron,
I have tried David’s method per his instructions posted here on Clayart. The only difference is that I used Darvan 7 rather than Darvan 11, which is unavailable to me.

Others, more recently have posted the benefit of adding CMC gum to the glaze (along with TCPP.) I like Davids's idea of adding CMC to "mixing water."

My experience, and I relate it back to what you do in your studio is most likely different than what I achieve in my studio. Following David's instruction precisely, my results appear to be over deflocculated. Perhaps because he uses Darvan 11 and I used Darvan 7. My process results in a rather thin glaze slurry. SPG around 140 (or 1.4). I think it is that "On a dry finger, bubbles will appear when the glaze is at the correct consistency is what I have not yet mastered. That is a matter of experience!

My result leads me to add Epsom salt to thicken the slurry to achieve a desirable thickness on a test tile, dipped for 5 seconds. I fire slow fire bisque to cone 06.

I have seen no degradation in fired results, except that the slurry is too thin. I either dip two or three times, or spray more thickness, until I add Epsom salts to achieve a proper consistency of the slurry.

Coments appreciated, experience is everything.
Thanks
Paul Randall

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From: Clayart <clayart...@lists.clayartforum.com> on behalf of ronroy--- via Clayart <cla...@lists.clayartforum.com>

Sent: Thursday, August 21, 2025 12:39:37 PM

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[ronroy--- via Clayart]

Hi Paul,

Because we are also talking about suspension of the glaze slop - what
is your experience with that?

RR

[Paul Randall via Clayart]

Hi Ron,
(Sorry, this got a bit long. Skip the first six paragraphs if you want.)

My experience with suspension is self-taught, mostly, but I’ve learned from following John Britt and by picking up clues from and some guidance from Clayart. I read a lot.

My only formal training in ceramics is undergraduate studio work; there was no glaze technology coursework offered. Daniel Rhodes "Clay and Glazes for the Potter" was suggested reading. Mr. Dingman simply brought us to the glaze studio, showed us the chemicals, the scale the scoop and the recipe box. His most memorable lesson was “get it all” referring to transfer of dry into the slop pail. All those glazes seemed to mix up well and there were no problems. That was cone 8, 9 and 10.

A lot of those glazes came from The University of Minnesota, as Mr. Dingman was an understudy of Warren Mackenzie. I did mix up some glazes that John Glick posted in a Ceramics Monthly article. I had good success with those. I had not yet encountered an unruly glaze slop. Or maybe I just didn't know.

After college, many years later when I built my first kiln and started mixing my own glazes, I began to encounter glazes that would hard pan. Or I would mix glazes with too much water. And all the problems associated with poor glaze slop became apparent to me.

At first, if a glaze hard panned, I would not use it. Had a couple pails sitting around. Same if the glaze crazed on the pot after application. I'd look for another glaze. But some of those glazes were very nice, so I began researching glaze technology.

And then I began firing to cone 6, it seems to me that glazes with things like Gerstley Borate and frits require more attention to suspension and an understanding of flocculation and deflocculation.

The basic tools I came down to manage suspension are:
1: Have enough clay in your glaze. All my glazes now have at least 2% Bentonite added. According to John Britt, glazes must have some clay if you want to manage suspension.

2. Use Epsom salts to flocculate glazes that:
a.) hard pan
b.) are too runny
c.) apply unevenly, runs easily

3. Use Darvan 7 to deflocculate glazes that:
a.) gels too thick as with Gerstley Borate
b.) needs less water, more solids, for example when spraying glazes. But also applies to dipping if glazes craze or flake off the pot when dry.

I have been successful using those tools and my glaze suspension and slurry performance have become much better. I spray a lot of my glazes and when spraying it is extremely important to have a good, well suspended glaze slurry that does not settle out in the gun or create runs when they are not wanted.

That's where I am at with managing suspension. I was attracted to David's method because it would be nice to control suspension and slurry characteristics at the time of mixing. I think that maybe not all glazes need deflocculation from the get-go. My results with that method so far still require piddling with both Darvan 7 and Epsom salts to get the slurry perfect. But with time and experience . . .

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[ronroy--- via Clayart]

Hi Paul,

Thanks for all that. Always enlightening to know what other potters are doing.

So much to learn and I have to say it - so much misinformation everywhere.

One lesson I learned - when I moved to the country and had to use well
water. Nearly all my glazes started hard panning from the minerals in
the well water.

I thought of using epson salts and did with the glazes already mixed
but after that I used only DI water - that’s de-ionized water,
distilled would work as well.

Problem solved.

[David Woof via Clayart]

Hi Paul,........ good going....... You said: "That's where I am at with managing suspension. I was attracted to David's method because it would be nice to control suspension and slurry characteristics at the time of mixing. I think that maybe not all glazes need deflocculation from the get-go. My results with that method so far still require piddling with both Darvan 7 and Epsom salts to get the slurry perfect. But with time and experience . . ."

Except that you used Epsom Salts to thicken your attempt to deflocculate with Darvan 7 because of using too much H20.
So when adding the Epsom Salt to make it thicker you caused your Deflocculation attempt to become Flocculated.
You can't now re-de-flocculate but since it is now thicker use it and try the de-floocculation on another batch. Hey? Smiles and Cheers and keep on going......Just use less initial H20 next attempt. (Let the Darvan 7 out to play first.)

And your first six paragraphs are essential for understanding what you already know and are now figuring out. Effective communication as well as teaching requires that the advice giver is aware of what the student already understands and has implimented.

This can be a bottomless glaze slop morass when posting on Clayart because of the obvious range of Ceramic experience, Level of interest in further study....and that some dear folks just want a short quick solution to the currant difficulty they are experiencing.

To your earlier posts My initial knee jerk response was to point out that you missed that de-flocculation requires less H20 to make a working glaze slop. But I decided to wait it out till I could see what you had figured out in your exchanges with Ron.

It is evident that you are a thinker and a learner. Now I see that you are willing to actually study. So your next learning curve would be to acquire a rudimentary familiarity with differiences in the electrical attraction/repulsion factors which give or change the polariety of clay particles so that they will either "Floc" or De-Floc" due to which Chemical agent we chose to add to the glaze recipe slop

Stating as simply as possible, in "flocculation" the clay particles are electrostactically attracted to each other and form "floc clusters" which cause a thickening of the glaze slop, so more H20 is required in the ratio of Raw Materials to H20 for application pourability. However these clustered Flocs are subject to gravity and while staying longer in suspension they are eventually overcome by gravity and settle.

This is where the problem of "Hard Panning" sets in. In this gravity settled flocculated slop when soluable salts are present either from tramp minerals in the water or from the Water Softener appliance.

*****In De-flocculation the particles' electrostatic polariety is reversed and the particles repell each other. They "De-floc" pushing each other away. This is the physical action keeping these particles in the glaze slop in suspension.
Note please**** if the deflocculation agent is powerful enough and the particles in the clay are small enough, the deflocculation condition will completely defy Gravity. I speak from proven Science, and from personal experience where I've let 5 gallon test buckets of deflocculated glaze sit for three years between use and found that while there was some observable material stratification, a quick stir brought the slop back ready to use for glazing.

I have been de-flocculating the majoriety of my glazes since 1981. Each time I've relocated (about every ten years) or,.... must substitute to a new Raw material, I adjust the glaze recipe ratios and the deflocculation protocol. There is a time to floc and a time to De-floc! Learning the basics of the physics and not being afraid to go after what we need will get us "home."

When recieving a gifted glaze recipe, does one recognize what/why each material is likely to contribute.

If a flocculant is listed like the very common "magnesium Sulfate" ((Epsom Salt) one is already in trouble if expecting an effecting of deflocculation. "Over doping" ie: adding too many/much flocculants reaches a point of no further effect.

****** However "over doping" of de-flocculants causes a reaction that causes an irreversable flocculation condition to occur.

PLease NOTE: Using the amount of H20 one is customarily useing in achieving a workable flocculated slop will be adding way too much H20 when attempting to deflocculate.

Flocculants include: Mauritic acid (hydrochloric acid) (HC1)
Magnesium Sulfate (Epsom Salt)
Calcium Cloride

*****Please Note: flocculants are acids, or "salts" that "act as acids."

And be aware that "Salts" are not necessesarily relared to Sodium (Na2)

*****De-floccuants: are suitable Soluable Alkalis.
To name several most common: sodium carbonate = soda ash, (sodium silicate the old time casting slip defloculant, but can be touchy tricky to use depending on type of clay.) Sodium Bi-Carbonate (baking Soda),
Darvan 7 and the improved more "stupid user friendly" Darvan 11 (why I welcome it) because I understand it's a" theory" not a precise formula to apply because adequate de-flocculation critially depends on the chemistry of the glaze recipe materials, and the mineral content of the H20 used. As in well water, vs treated Municipal Water sources, vs the sodium in a private "water softener.

Yes there are papers written where some one who obviously was simply republishing an older work and gave away that he didn't understand what he was trying to sound knowledgable about by stating that "it was counter intuitive." Ho'Wha!!! Nah"gah!!!

I've posted previusly regarding the benefits of deflocculation vs the troubles some folks experience regarding over saturated bisque bodies that lend to glaze spitting and crawling during early stages of firing. Deflocculated glazes brush apply better .... the list can go on. it's in the Clayart archives....

Misneach,

David Woof......................................................................................................................................................................................
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From: Clayart <clayart...@lists.clayartforum.com> on behalf of Paul Randall via Clayart <cla...@lists.clayartforum.com>
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[David Woof via Clayart]

Hi Ron, you said: "I'm not saying it does not work but I have always thought that

formulating a glaze that does not need flocculating is the better
solution.

Yes to the "better solution".....But....
I respond that many times potters seeking advice for how to keep glazes longer in suspension are advised to use Thickening chemical agents. Most times these thickening agents are or include Epsom Salts (Magnesium Sulfate) and or HC! (Hydrochloric Acid... AKA Muriatic Acid)
Please note: These are well known "Flocculants"

Un-recognized by many is the fact that they were just advised to*** Flocculate*** their glaze slop. This chemical addition thickened the slop.... so merrily off we go cuz "we" don't need to know why or how it works!!! Till something else goes wrong because we will always have Clayart experts to help keep us functioning.
Accurate knowledge is power, but Guess if it works, one doesn't need to bother to learn the how or why.

A reminder; in times past I have filled the archives with information on the very valuable merits to know and understand of "De-floccuation" and I just wrote a Paul a rather lengthy post including a teaser to pique his interest on the Electrostatic forces of attraction vs repulsion that make flocculation/de-floccuation possible and understood as far as us potters need to know to effectively apply.

As far as you saying that you think I alone De-flocculate.... Off list I have a number of folks communicating their experiences. Some successfully, some at different phases of experimenting and learning. I also taught Art and Ceramics at two institutions of higher learning. In Ceramics: the last word will never be written.

Ron,..... said with deep respect for you as a person and all you have contributed, I don't feel the need to get sucked in to further defense on this subject. I'm not interested in converts. Just interested in sharing my "mud pies" with those who may see something to enhance their Pottery Glazing experience.

Be well old soldier,
Sending Much Love your way....
David Woof................................................................................................................................................................................
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From: ron...@ca.inter.net <ron...@ca.inter.net>
Sent: Thursday, August 21, 2025 11:39 AM

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Cc: David Woof <woof...@hotmail.com>

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[Paul Randall via Clayart]

David,
Thank you for this. The underlying physical properties are good to understand, I always put them on the shelf in the library of my mind. When I need that information to further understand, it remains there for me. I have always had the ability to recall that sort of thing, although with age it may take one more beer (or time) to get things to float to the surface.

Regarding your method of deflocculating while mixing, the issue of specific gravity has crossed my mind. Do you use SG to ensure a consistent result from glaze session to glaze session? If one defloc's whilst mixing less water is required, which of course changes the SG of the final slurry. The number will be higher; it seems to me.

I have been using SG to keep consistency in the past. But it occurs to me that your method as described relies more on one's judgement. Of course, when the mix is judged right using the finger method, one could measure SG and then use that as a measure for consistency over the life of the batch and from batch to batch.

Will you please comment?

Thanks
Paul Randall

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From: Clayart <clayart...@lists.clayartforum.com> on behalf of David Woof via Clayart <cla...@lists.clayartforum.com>
Sent: Thursday, August 28, 2025 1:43:05 AM
To: New Clayart 2024 Clayart <cla...@lists.clayartforum.com>
Cc: David Woof <woof...@hotmail.com>
Subject: Re: [Clayart] Using frit as a substitute/ NOW De-flocculation and Flocculation

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[ronroy--- via Clayart]

Hi David,

I was answering your question re why I never recommend over
flocculation to help suspend glazes. I was trying to say in all my 65
years of contact with clay and glazes I had never heard of it except
by you. I therefore did not seem qualified to offer advice.

Did you not understand what I was saying? Perhaps I should have been
more explicit. Probably I was sending two answers at the same time and
that led to some misunderstanding?

I now remember that the American shinos are over supplied with soda
ash and are therefore over flocculated and do remain in suspension
quite nicely.

Still - solubles in glazes can lead to problems and having that
information can help if problems arise.

I remember a case when I was problem solving for a clay company. They
were adding Epsom salts to some bodies to combat defloccing. A
customer was getting bubbling on rims out of the glaze fire. Because
the ware was dried in an upright position the dissolved salts were
rising to the rims and being deposited there. This lead to over firing
at the rim and causing the bubbling. The cure was to reduce the amount
of Epsom by half and custom mixing that body for her.

If she had dried the ware upside down it would not have happened not
at the rims but at the feet. That may have resulted in sticking to
shelves depending of what the shelves were made of.

I wonder if, when we all decided that clay and glazes the right thing
to do, did we have any idea just how complicated this all is!