[Clayart] Density of glaze is one part

[Paul Randall]

I remember reading Ansel Adams’ The Negative, struggling to grasp his ZONE System. Though a brilliant photographer, Adams’ explanations were complex. Then I read Fred Picker’s Zone VI Workshop, which clarified concepts like “Base Density Plus Fog” and “Maximum Required Density." Zone VI is middle gray.


After mastering the Zone System on my own, my professor handed me How to Be Positive About the Negative. The author, whose name escapes me, simplified the method into a practical procedure with a spot meter, Tri-X Pan film, and D-76. Following his method, it worked—mostly.


I also recall taking Thermodynamics I twice, listening to Professor Joshi’s confusing lectures. Then one day, over beers with my friend Rick Meyers, he said, “You can hit a ball farther on a hot, humid day!” Suddenly, everything clicked. I was annoyed—Joshi could have used simpler examples like that.


When rebuilding my wood/gas kiln, I asked about chimney size here on Clay Art. Someone mentioned passive dampers—a simple, brilliant idea. “Playing the kiln like a musical instrument” was a revelation.


It would be nice if mixing glazes, understanding rheology, specific gravity, Darvan 7 or 11, Epsom salts, slop and slurries could be distilled into a simple “aha” moment. The finger thing gets close but requires experience to get there. Although I've never seen a fired finger that I could hold up a say "See, my finger method works."

Paul





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From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of David Woof via Clayart <clayart at lists.clayartforum.com>
Sent: Friday, February 21, 2025 12:24:35 PM
To: Clayart international pottery discussion forum <clayart at lists.clayartforum.com>
Cc: David Woof <woofpots at hotmail.com>
Subject: Re: [Clayart] Density of glaze is one part

Mel you said:<"Take your finger and stick it in the bucket...check your fingernail for glaze thickness.  It is like throwing two hundred pots and they are all ¼ inch thick.  How did you know?  experience. I do not use math, I use my senses.">

Yes I like my trustworthy finger as well.  Have used it for many Years and many Glazes, while assured of complete success.  It never needs batteries, and even if I broke it, it would still work........ And hard to lose it, misplace it, or have it stolen.

I dip my completely dry finger in the well-mixed glaze slop.  The glaze is the right specific gravity and thus rheology when the air in the stirred glaze and whorls of my finger print escape thru the dipped finger glaze and appears as bubbles breaking the surface.
With no observed bubbles breaking on the surface? Still too thick!    Add a "wee bit more H20, or a wee bit more Darvan 11.
(FYI ..... Darvan 11 is even more user friendly than Darvan 7)

Misneach,

David Woof...........My Muse is attempting an imaginary faking of speaking English as a first language this morning, and thanks me with grins for last night's explanation and demonstration of the difference between 'De-flocculation and De-frocking.'  Since she is not a priest, and an old English word for a dress or gown was "frock".........I must have explained it to her satisfaction.
Now watching me write about my glaze dipping finger dripping, she grins and sez: "No batteries huh? Hard to lose it or have it stolen as long as you don't "give it" to someone!"   Then the little Raven-Haired Vixen widens her deep brown eyes and mischievously dances away with a playful throaty chortle.............................................................................................................................................
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From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of melpots via Clayart <clayart at lists.clayartforum.com>
Sent: Monday, February 17, 2025 4:01 PM
To: clayart <clayart at lists.clayartforum.com>
Cc: melpots <melpots7575 at gmail.com>
Subject: [Clayart] Density of glaze is one part

In Japan we glazed pots with a large second hand of an old clock.
Bucket of glaze, dipper with cup on the end.
Fill pot with glaze, count the seconds, dump out and roll the pot in your hand and the drip goes away. Perfect coat of glaze.   do one hundred pots and count every time.

So, if your glaze has too much water, count to 8 seconds, if it is too thick, count to 5 seconds.

I start my glazing by dipping a piece of bisque in the bucket, count to 6 and take it out....then take a pin and check the depth.  If I am working with thin glaze I might be double dipping with the second dip for 4 seconds.  Check with a sharp pin.

I stir the glaze with the dipper before each pot.  Some glazing chems drop to the bottom fast.  I see people glazing with colored water, and all the glaze materials are in the bottom of the bucket.

I stir my glazes and say to self...is it milk, ½ and ½ or whipping cream.???
Take your finger and stick it in the bucket...check your fingernail for glaze thickness.  It is like throwing two hundred pots and they are all ¼ inch thick.  How did you know?  experience. I do not use math, I use my senses.

And every glaze recipe has its own unique qualities.   And for sure, glaze families that are the same make great multilayers.

Shino hates other glazes and makes a mess.  5x20 loves layers and makes pretty things. A strong deep foot ring is a potter's best friend when glazing.
mel
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