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Hudson River Clay


GreyBird
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I’m feeling a bit OCD. I thought I’d get cool enough results from this batch of tests so I could be satisfied and move on to throwing because that is REALY what I need to be doing. But alas although a lot was learned… The Hudson Wonder Glaze is still eluding me.

Starting from top is the originals which shivered like hell…. But the colors, I thought were beautiful. I loved the toasty color of the breaking edges of the Old Gold Albany and the accents of the Hudson Clay where it pooled (I thought) within texture. So I did the following - None of which shivered but all of which are but ugly with the exception of maybe the Albany Version of #3, so third down on the left. That is if you are looking for a solid glossy color showing no cool depth of field or character over texture at all…. So yea, I guess they are all but ugly.

The left side uses Albany Slip, The right Hudson Clay

Row #1: Albany Slip/Hudson (AS/H) 78%, Lithium Carb (LC) 10%, Zircopax (Z) 12%

Row #2: AS/H:80%, Potash Feldspar (F):20%

Row #3: AS/H:70%, F:20%,  Z:10%

Row #4: AS/H:70%, F:10%, EPK:10%, Z:10%

Row #5: AS/H:70%, F:20%, Ball Clay:10%, Z:4%

I realized when I went over the results that I forgot to just drop the Lithium Or at least drop it to 5% … Next batch!

I think line blends are the only way to proceed at this point. I will try one with this Albany Clear which Fred Sweet was kind enough to send me last year. In fact I’ll now try all of his Albany Recipes since I’m fully committed to the maze of rabbit holes at this point….

It’s Called: V.C. Easy Gloss III

Gerstley Borate 50.00
Albany Slip 25.00
EPK 25.00

There was also this Ravenscrag Slip Glaze Recipe I tried which I must have forgotten to put the oxides in because it came out this beautiful satin very off white and was supposed to be a beautiful Satin Olive Green. I may try some brushwork with the Hudson clay over this glaze. Who knows! Or even just flicking it over may be a cool effect… So much more testing to do.

I obsessed like this over creating mugs that I was happy with. It took years but I finally love them. Now I just have to make about 50 more to populate all of my outlets so I can move onto the next thing. Does everyone obsess over everything like this? I feel like I am driven to complete the process before I can begin another and the process is not just throwing a piece and moving on, but experimenting until you love every aspect of it then making a stock pile… then you can move on.

From the Rabbit’s hole: “There is a place. Like no place on Earth. A land full of wonder, mystery, and danger! Some say to survive it: You need to be as mad as a hatter.”

IMG-2909.jpg

Ravenscrag.jpg

Edited by GreyBird
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Mary:

still working on some variations. Will post some pictures tomorrow? Been playing with some soak ramps to produce color/ crystals. Magnetite prefers higher soak temps (1925F) shows red, 1750F goes to amber, gold, dark brown. I fired one over the weekend using zincite (metallic zinc) which at cone 6 has better fluxing ability than lithium. Carb. But it also effects color.

I made up 2000 gram test batch of pure porcelain using Hudson as the plasticizer. Rather responsive for only adding 5% Hudson. Like I said earlier, lots of calcium bentonite, probably some hectorite: rather plastic. I will send the porcelain to you to play with, after all it is your discovery. You should get a package tomorrow, something to help you on your journey.

T

by the way: Hudson likes sodium better than potassium. Check your analysis sheet.

Edited by glazenerd
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12 minutes ago, glazenerd said:

Mary:

still working on some variations. Will post some pictures tomorrow? Been playing with some soak ramps to produce color/ crystals. Magnetite prefers higher soak temps (1925F) shows red, 1750F goes to amber, gold, dark brown. I fired one over the weekend using zincite (metallic zinc) which at cone 6 has better fluxing ability than lithium. Carb. But it also effects color.

I made up 2000 gram test batch of pure porcelain using Hudson as the plasticizer. Rather responsive for only adding 5% Hudson. Like I said earlier, lots of calcium bentonite, probably some hectorite: rather plastic. I will send the porcelain to you to play with, after all it is your discovery. You should get a package tomorrow, something to help you on your journey.

T

by the way: Hudson likes sodium better than potassium. Check your analysis sheet.

So Minspar instead of potash spar?

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20 minutes ago, glazenerd said:

Mary:

44% Hudson, 20 silica, 10 Nep Sy, 7 lithium. Carb, 18 spodumene, and 5 bone ash. 1750F hold (30 min.) nice chestnut color. Extremely reactive to application thickness.

image.jpg.2101c9d993a7ecf45ad9d220dad0c398.jpg

WOW, that is wonderful results! That's like cone 08 right? It looks semi transparent. Might look nice over underglazes or ever texture. I would like to make something similar to work at cone 6. Also, I got the porcelain you sent today :) Should I use it as a clay body? Thank You!

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Mary:

fired to 2230F (cone 6) and soaked at 1750F for 30 minutes. The package you received was suspender/ brushing medium. It acts like a gum, but it is a blend of natural clays. Use 2-10% (pending application), better to dry blend but you can  wet blend without clumping. Stir as you add water, it will thicken over a 30-45 second period. Will send you the premixed porcelain this weekend. Been sorta playing with it :)

t

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Oh, I see... Thanks again! OOOh and the glaze, I will try that! My kiln has only a kiln sitter, no digital controlled soaks :( but, maybe it will still be good. My small test kiln I can program in a soak, but the large kiln I could not do that.... Unless I watched the temp rise with the pyrometer and then turned switches down to medium 1750, to hold temp without rising for 30 minutes, then all switches back up to high...yea, I could do that!

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On 8/25/2018 at 6:15 AM, glazenerd said:

Grey:

glazemaster is a program written by John Britt and Ron Roy ( clay mode).

this clay already has 4.64% KnaO ( molar), which is a truck,load. Total fluxes 13.41%- Typical cone 6 porcelain is 3.89, and cone 6 stoneware 3.29%. Adding a premix which has even more KnaO could cause problems; especially if Nep Sy has been used as the body flux. Then again, I understand the desire to experiment: I will show you my collection of rabbit holes some day.

typical Si/Al ratio is 4/1, this clay is 5/1. Adding straight kaolin is the easiest way to get the Si/Al in line for C6. 

T

Glazenerd... I am taking an online Glaze calculation course which says the SiO2/Al203 ratio should be 7/1 as per Stull chart (attached) So now wondering why you are saying it is typically 4/1? Is that because we are targeting cone 6? although he goes on to point out that even lowering the temp. the ratio remains at 7/1 - Quite possibly something I haven't learned yet and I'm jumping the gun, but just wondering... quicker to ask you probably than to wade through the hours and hours I have left in this course to get the answer.

Nothing against the course, it's really a great resource, but it's maddening for me when teaches don't get right to the point...  too much talking confuses the issue. So does the constant slurping on a big gulp. Nothing more distracting than that. He might as well be dragging his nails down the chalkboard every 5 minutes. Gosh I hope no one hear made the course!.... On the upside. It is very informative. I just think it could have been covered in like two hours instead of I think it's 21 hours. Somebody stop me... wonderful course, really!

Stull.jpg

Edited by GreyBird
Corrected Course Hours
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43 minutes ago, GreyBird said:

Glazenerd... I am taking an online Glaze calculation course which says the SiO2/Al203 ratio should be 7/1 as per Stull chart (attached) So now wondering why you are saying it is typically 4/1? Is that because we are targeting cone 6? although he goes on to point out that even lowering the temp. the ratio remains at 7/1 - Quite possibly something I haven't learned yet and I'm jumping the gun, but just wondering... quicker to ask you probably than to wade through the hours and hours I have left in this course to get the answer.

Nothing against the course, it's really a great resource, but it's maddening for me when teaches don't get right to the point...  too much talking confuses the issue. So does the constant slurping on a big gulp. Nothing more distracting than that. He might as well be dragging his nails down the chalkboard every 5 minutes. Gosh I hope no one hear made the course!.... On the upside. It is very informative. I just think it could have been covered in like two hours instead of I think it's 21 hours. Somebody stop me... wonderful course, really!

Stull.jpg

I think he was referring to your clay, not the glaze

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Correct Liam; 4:1 Si/al ratio is for clay bodies.  

Mary: research "eutectic" in relation to glaze. In glaze, you want a complete molten melt that forms a glass (glaze.)  in clay, you want a glassy matrix that melts just enough to create a solid mass that prevents liquids from passing through. (Absorption).  Alumina is highly refractory: the ratio effects the melt. A 7:1 Si/al ratio in clay would cause slumping.

a basic glaze is silica, alumina, and flux. The wide variation accounts for the % of silica! alumina! and flux of individual materials.(and why does this ipad replace my comma with exclamation?)  for instance; Custer spar hovers around 10% potassium!while mahavir is slightly above 13%. A glaze calculator is just keeping a running total. After that, materials are used to control flow , raise or lower melt temps, or specific effects. If you spent one evening just looking at the material analysis of common materials such as Nep Sy, minspar, Custer, mahavir, dolomite, etc. the differences in flux content, silica, and alumina will paint the story of why more or less of each is used.

the basic flux rule is: sodium is cheap and produces a low viscosity ( runny) melt, potassium produces a low viscosity, but higher than sodium. Potassium in USA is three times the price of sodium; which is why sodium is used in more recipes. Calcium is high viscosity ( stiffer) and used to control flow.  Very simple premises, but a good starting point.

look at the Currie Grid thread that Curt started. You can visually see what more or less silica, or more or less alumina does to a base glaze. Curie Grid is a visual reference of  the Stull chart you posted. Which is why I fire crystalline glaze, because it is based in the MTS formulation theory ( melt that sh......t ) right Dick? :o

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Huh? Somebody called me? Yup, MTS. A crystalline glaze would not even be on the Stull chart. Alumina UMF levels are typically below 0.05 and Stull's shaded area stops at 0.1. Silica UMF as a number by itself is typically too low at 1.5 to 2.0, but with the non-existent alumina, the SI ratio is at a mind-bogling 35-50 compared to the 7 in a "normal glaze".  So we MTS out of it and leave it sit molten until the zinc gets tired. And not that it really matters, a nit I noticed in one of the quotes... The Glazemaster program was written by John Hesselberth, not John Britt. John H and Ron Roy together wrote the book Mastering Cone 6 Glazes, but John wrote the computer program. Glazemaster is my go-to calc program and I have way too much data in my copy if anybody needs some. Also willing to answer how-to questions from other users.

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On 9/24/2018 at 9:45 PM, glazenerd said:

Mary:

still working on some variations. Will post some pictures tomorrow? Been playing with some soak ramps to produce color/ crystals. Magnetite prefers higher soak temps (1925F) shows red, 1750F goes to amber, gold, dark brown. I fired one over the weekend using zincite (metallic zinc) which at cone 6 has better fluxing ability than lithium. Carb. But it also effects color.

I made up 2000 gram test batch of pure porcelain using Hudson as the plasticizer. Rather responsive for only adding 5% Hudson. Like I said earlier, lots of calcium bentonite, probably some hectorite: rather plastic. I will send the porcelain to you to play with, after all it is your discovery. You should get a package tomorrow, something to help you on your journey.

T

by the way: Hudson likes sodium better than potassium. Check your analysis sheet.

Hi Glazenerd, So I've been studying hard on this. If I am correct, for a glaze, my Si/Al ratio is fine for cone 6 at 5/1 . But the Flux ratio is way off. For a .3 to .7 ratio between R2O and RO, I am short 26.6% RO (Alkaline Earth), not Alkaline Metals. So so adding 26.6% whiting or bone ash to the Hudson River Clay may work alone as a glaze? I've attached an image of my messy worksheet. LOL I know I must be wrong on this so please if you don't mind pointing out my error, that would be so very appreciated. For starters I wasn't sure if the .3 to .7 ratio is in % or moles or if it eve matters so I did the math with both but ended up using the original % Numbers.

PS, remind me, why does Hudson clay prefer Sodium to potassium?

HVC 2.jpg

Edited by GreyBird
another question added :)
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Hi Mary,

If you are getting serious about this ceramic chemistry stuff (and from the picture above it looks like you are), time to get yourself some glaze chemistry software!  Will make your life a lot easier and calculate all those things very easily (and accurately!), leaving you more time to tweak and do analysis.  Just saying.  :-)

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GM Mary:

from a quick glance, looks like you are analyzing just the Hudson? I mentioned earlier that the chemistry for melting this slip falls into the abyss: neither glaze or clay chemistry is wholly applicable. Typically the maximum clay % added to a recipe is 20%, and that is primarily done to boast alumina content and to control drying/flaking issues. In this scenario, clay accounts for 50-75% of the recipe: which brings in some parameters from clay chemistry. 

In glaze chemistry, you formulate for a complete eutectic melt at a prescribed cone range. In simple terms, as the cone temp rises, the flux levels decline: the additional heat compensates. In clay chemistry, the general premise is the same for fluxes in regards to temp doing  the heat work. However, you are not after a complete melt in clay; but rather enough melt to produce densification of materials to reach a prescribed absorption rate. Functional work should be 2% absorption or under: non-functional has no set limits.

Hudson slip has both some applicable glaze chemistry, and some applicable clay chemistry due to the high clay content. 10% lithium additions to a standard glaze recipe would make it flow like a river; while that same 10% in clay is just enough to produce some glass? So in dealing with Hudson clay specifically, UMF will only give a generalized insight.

I will finish this later, out of time. Aunt died Sunday, I have to go pick up mom and take her over there. 

T

 

Edited by glazenerd
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57 minutes ago, glazenerd said:

GM Mary:

from a quick glance, looks like you are analyzing just the Hudson? I mentioned earlier that the chemistry for melting this slip falls into the abyss: neither glaze or clay chemistry is wholly applicable. Typically the maximum clay % added to a recipe is 20%, and that is primarily done to boast alumina content and to control drying/flaking issues. In this scenario, clay accounts for 50-75% of the recipe: which brings in some parameters from clay chemistry. 

In glaze chemistry, you formulate for a complete eutectic melt at a prescribed cone range. In simple terms, as the cone temp rises, the flux levels decline: the additional heat compensates. In clay chemistry, the general premise is the same for fluxes in regards to temp doing  the heat work. However, you are not after a complete melt in clay; but rather enough melt to produce densification of materials to reach a prescribed absorption rate. Functional work should be 2% absorption or under: non-functional has no set limits.

Hudson slip has both some applicable glaze chemistry, and some applicable clay chemistry due to the high clay content. 10% lithium additions to a standard glaze recipe would make it flow like a river; while that same 10% in clay is just enough to produce some glass?

I will finish this later, out of time. Aunt died Sunday, I have to go pick up mom and take her over there. 

T

 

Very sorry for your loss :( ttyl. You and yours will be in my thoughts.

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3 hours ago, curt said:

Hi Mary,

If you are getting serious about this ceramic chemistry stuff (and from the picture above it looks like you are), time to get yourself some glaze chemistry software!  Will make your life a lot easier and calculate all those things very easily (and accurately!), leaving you more time to tweak and do analysis.  Just saying.  :-)

Hi Curt, I rather enjoy doing things by hand. I'm old school that way. Once I understand it thoroughly enough I may switch over to Glaze software. In the meantime my understanding is that Glaze or Clay body all comes down to the same elements. So while this Hudson Valley Clay has a lot of Silica and Alumina, it is also has the other required elements to make it a glaze, only missing the correct amount of Alkaline Earths Fluxes to make it a glaze... The exact amount being 26.6 Grams if I am mixing a 100g test batch.

I did try glaze software once a few weeks back and didn't understand at all how to use it.

I have to make bird chop today but after that I'll start testing again. ... and watching the rest of the course. We all know I have the patience of a (insert clever simile here).

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When I finally broke-down and started using software my understanding of how materials relate in a melt drastically improved.

The first time I plotted a series on a Stull graph and could see the tiles corespond to SiO2/Al2O3 ratios I knew how much time/energy and money I wasted trying to 'wing-it'.

I'm still a big fan of just melting stuff to see what happens. There are lots of glazes that exist near and outside the accepted margins but now I know where some 'functional' lines are drawn.

I wholeheartedly agree with @curt. Glaze software changed my life.

:)

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Thanks Curt. Just so you understand though, I'm no longer "Winging it" I understand the Stull graph and I can see that this Clay, as a glaze (as is )falls in the matt range and by understanding the required Si/Al ratio along with the .3/.7 ratio of fluxes in all glazes I am beginning to understand what I have here in the Hudson Clay. I do hear you about the software, but I don't think it can teach you quite at the level that I am looking for and like I said I did get it and I plugged all the ingredients I have in this clay into it and then just stared at it blankly, not understanding what to do next, so it was not very intuitive for me. Not to mention, I paid a LOT for the online course. So I'll finish learning what I can there and then maybe explore Glaze software. The teacher did mention Glaze Software was the way to go but first it helps a lot to understand the underlying chemistry and I'm having fun with it so I'll get to the software thing eventually but first let me have fun drawing out my little graphs. LOL.

Edited by GreyBird
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7 minutes ago, GreyBird said:

Thanks Curt. Just so you understand though, I'm no longer "Winging it" I understand the Stull graph and I can see that this Clay, as a glaze (as is )falls in the matt range and by understanding the required Si/Al ratio along with the .3/.7 ratio of fluxes in all glazes I am beginning to understand what I have here in the Hudson Clay. I do hear you about the software, but I don't think it can teach you quite at the level that I am looking for and like I said I did get it and I plugged all the ingredients I have in this clay into it and then just stared at it blankly, not understanding what to do next, so it was not very intuitive for me. Not to mention, I paid a LOT for the online course. So I'll finish learning what I can there and then maybe explore Glaze software. The teacher did mention Glaze Software was the way to go but first it helps a lot to understand the underlying chemistry and I'm having fun with it so I'll get to the software thing eventually but first let me have fun drawing out my little graphs. LOL.

Mary, I think you may be responding to C. Banks rather than myself with this? 

In any case I hear you, and one does have to come to it in one's own time.  It is true that the software on its own can be rather confronting at first encounter.  In fact the software is only a tool (rather than a teacher), and like all tools it does require some knowledge - probably the kind you were getting in the online course - to use it for effect.  Or you have to spend plenty of time reading and reflecting on the online help and documentation for the software, which in many cases will teach you much glaze and clay chemistry along the way as you learn how to use the software.   I can tell you from experience that Insight is very good for this, but I am sure other packages are as well.

Ultimately, for the software to be useful you have to know enough glaze chemistry to understand what questions can be asked of the software, and how to interpret the answers.  Then it becomes very powerful for manipulating clay and glaze recipes to turn them in to what you want...  For instance, is the .3/.7 ratio of R2O to RO fluxes you mention above a magic ratio, or would .4/.6 be OK?  What about .2/.8?  And would the answer be different if you add boron?  Or phosphrous (bone ash)?  Or maybe lithium...    The rabbit hole beckons...

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