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GreyBird

Hudson River Clay

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12 hours ago, liambesaw said:

Looks like an octopus hugging a whale heart.  Pretty awesome!

So basically, the culmination of those old nautical illustrations, of the giant squid, fighting the whale.  Cephalopods: 1    Mammals: 0

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18 minutes ago, Benzine said:

So basically, the culmination of those old nautical illustrations, of the giant squid, fighting the whale.  Cephalopods: 1    Mammals: 0

I wish I could claim such a knowledgeable origin to the idea behind the piece, but I can not. I just did what I felt to do and there you have it. LOL.

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I see now what my error was in mixing the Hudson River Clay glazes and yes, it seams I mixed them all improperly, not just the one that looked obviously bad...

When I altered the ingredient amounts to make the correct is/al ratios the batch no longer ads up to 100 so you can't just add your additional ingredients in grams and then the rest in Hudson Valley clay to make the batch add to 100. So I had HRC30 which is HRC with 30% whiting so 1000g of HRC and 300g of whiting NOT 70g of HRC and 30g of whiting. And so on... HRC103010 should be 1000g HRC, Gerstlry 100g, whiting 300g, frit 3134 10og easy enough to fix... just need to add the additional HRC to each. Thank God!

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OK, I know this is probably getting old for folks, but I thought I had a good grasp on things after I took the online glaze calculation course and developed my last batch of Hudson River Clay tests before I went away for a little over a month. After coming back I realized that I couldn't remember why I did what I did so I went back through the class lectures where needed, and realized I had some funky ideas in place and couldn't trace where they came from. So I re-examined the formula. In order to reach R2O:RO: 0.5:0.5 In order to fire to cone six, I only need to add 10% whiting & 10% Lithium Carb. That lands me squarely at .5/.5 Not sure how it will pan out in reality but when I looked at the ratio of my last batch where I added 30% whiting it was way off. It was at .1/.9 The other which was 30% whiting, 10% Gerstley Borate & 10% frit 3124 was also .1/.9 I'm surprised they worked at all. So back to the basement to make more test tiles! Yikes.

This clay naturally starts with a .3:.7 ratio so that's amazing. The Alumina is quite high. The Si/Al ratio is 5:1 but that's still on the Stull chart. It should work. We'll see.

Edited by GreyBird

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Great reading in this thread, I have access to heaps of clay as we are building 18km of motorway through the north island in New Zealand.

Had some very good results to date with clays firing happily to cone 13 along with a few explosions of course.

Nice to start understanding how I can run some tests in an organised manner instead my usual, rougher manner...  

Thanks for sharing and good luck with the Hudson Clay!

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9 hours ago, jafa5 said:

Great reading in this thread, I have access to heaps of clay as we are building 18km of motorway through the north island in New Zealand.

Had some very good results to date with clays firing happily to cone 13 along with a few explosions of course.

Nice to start understanding how I can run some tests in an organised manner instead my usual, rougher manner...  

Thanks for sharing and good luck with the Hudson Clay!

Good luck to you too! I'm at the point where I am realizing there are no shortcuts. Even with my recipes that have nothing to do with local clay... I really ever only needed a few good bases (Gloss and Satin Matt) then from there I can develop my bank of colors and combinations instead of just mixing glazes willy nilly from found recipes.

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OK, happy day! :) I have finally gotten to running more glaze tests. I am Soooo very excited about the results. Here are three new tests of the Hudson River Clay glaze. I wish the sun was out so you could really see the color variation better. I was able to re create the original that I loved so much with the toasty edges (3rd tile) the first tile is what I'd expect from the clay after seeing what others have done with it. But the second is a whole new happy accident! Whoa, what a feast of reds to black on this one ❤️❤️❤️ Now I'll mix up a large bucket of those two favorites and retest to make sure I'm still on target before I put on any pieces... But I'm pretty sure I've turned a corner on this long road and finally got my own beautiful, unique glazes made from local clay.

 

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10 minutes ago, Babs said:

Like a beagle on a scent!!!

Love your results. Are your test tilles made frkm sections of a thrown plate. Doing a great job.

Hi Babs, I usually throw a large low casserole type shape about 2" or 3 " then remove a circular section of the bottom while it is still on the wheel leaving about a 1/2" foot. When it firms up a bit I just slice it up, stamp each piece for so I can see how it breaks over a pattern and cut holes for hanging in the top with a simple hole cutter. This way they have a little foot to Stand upright in the kiln and they hang nicely on a chord. I have to make more, I'm fresh out! Its also good to make them in Porcelain and stoneware as the glazes act so differently on Porcelain.

Edited by GreyBird

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2 hours ago, glazenerd said:

If no one else will, then I will post a line from the Tina Turner classic

"Proud Mary keep on Rollin".    And you should be proud. Figuring out a recipe is not easy.

T

LOL... Thanks Tom !

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2 hours ago, glazenerd said:

If no one else will, then I will post a line from the Tina Turner classic

"Proud Mary keep on Rollin".    And you should be proud. Figuring out a recipe is not easy.

T

and credit to John Fogerty and Creedence Clearwater Revival

"In the beginning, "Proud Mary" had nothing to do with a riverboat. Instead, John Fogerty envisioned it as the story of a woman who works as a maid for rich people. "She gets off the bus every morning and goes to work and holds their lives together," he explained. "Then she has to go home."

Proud Mary - Songfacts

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OK, I think I just can't give up the experimenting bug. So now I'm thinking what colorants will work well with this glaze? I am going to try what is used for Waterfall Brown in "Mastering Cone 6 glazes". It makes a lot of sense since this clay has such a high Iron content and waterfall brown utilizes that. So I'll add 3% Red Iron Ox since the clay already has 7% and 1% Rutile. Should be fun!  Hmmm, also I wonder what would happen if I added Opacifiers. Maybe I need to do a triaxial blend with it :)

Edited by GreyBird

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Its funny how things work out sometimes... I had posted a photo from a book a while back which pictured a "rust red"platter. I had to take the photo down as it was copyrighted, but the discussion talked a lot about obtaining the red I was looking for that I saw on that platter. I had given up on the idea after many failed tests. And subsequently moved on to develop the Hudson River Clay glaze. The last tile I pictured here in this post showed some really great rust red blooming from the dark glaze. I fired that in my test kiln and matched the heat rise and fall of my large kiln, or so I thought. Until I went to run these two mugs when I noticed that after it reached temp I had the numbers put in wrong and the kiln actually cooled much quicker than it would have in my large kiln. So I fixed the error and let the cups fire with a slow cool of 190° per hour to like 1490 the let it cool the rest naturally. The results were a rust red alternating with shiny black very similar to that elusive platter red I was trying to achieve. I do have a question in all of this... Notice how the clay appears stained reddish from about 1/2" from the bottom up. I'm sure the cups were clean when they went in and not sure where this discoloration is coming from. could it be that the Iron soaked from the glaze through the clay? Maybe if I cool at 200° per hour or let it cool naturally next time it'll have less time to soak through?

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Mary said:  “Notice how the clay appears stained reddish from about 1/2" from the bottom up. I'm sure the cups were clean when they went in and not sure where this discoloration is coming from. could it be that the Iron soaked from the glaze through the clay?”

 

try a thin wash of either baking soda or soda ash on raw bisqued area and see what happens.  I get an orange stain in high fire reduction;  some colleagues have gotten orange flashing at cone 6 oxidation.  

LT

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2 minutes ago, Magnolia Mud Research said:

Mary said:  “Notice how the clay appears stained reddish from about 1/2" from the bottom up. I'm sure the cups were clean when they went in and not sure where this discoloration is coming from. could it be that the Iron soaked from the glaze through the clay?”

 

try a thin wash of either baking soda or soda ash on raw bisqued area and see what happens.  I get an orange stain in high fire reduction;  some colleagues have gotten orange flashing at cone 6 oxidation.  

LT

So do think the orange color on the plain clay part is coming from some sort of soda ash or baking soda in the glaze?

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