C.Banks

I followed the 10:1 rule from Olsen (firebox : flue size) on a similliar project and found I did not get enough pull with a 9 foot chimney of 81 inches in area. I came to the same conclusion that the exit flue is too small. I liked the idea of a fast fire kiln but in my case there were other issues with the depth of my firebox in relation to the heigth of the kiln.
I haven't got back to it but I'll rebuild with twice the flue size and look more closely to a ground hog deisgn with a low, wide chimney instead of the tall, narrow fast fire design.
Established kilns I've been a part of have run into heat saturation issues atfer too many hours of struggling with what amounted to overloading. I bring this up in repsonse to @Biglou13 as I'm sinscerely curious if your design has the mass to succeed as anything other than a fast fire. I don't mean this as a criticism I only mean to work out what expectations we should have from kilns with less mass.

https://ceramics.org/publications-resources/ceramic-tech-chat/
The American Ceramic Society always seemed a bit exclusive for commoners like me but it turns out they do share.
An interesting note - I overheard an industry type person talking to a recognised academic about recycled glass and how there is a need*/opportunity to find a use for it. It's not the first time I've heard of people trying to peddle ideas for recycled glass. This: https://ceramictechchat.ceramics.org/974767/12251109-the-everlasting-relevance-of-brick-john-sanders briefly brings up the possibility of making brick with up to 60% recycled glass.

https://ceramics.org/publications-resources/ceramic-tech-chat/
The American Ceramic Society always seemed a bit exclusive for commoners like me but it turns out they do share.
An interesting note - I overheard an industry type person talking to a recognised academic about recycled glass and how there is a need*/opportunity to find a use for it. It's not the first time I've heard of people trying to peddle ideas for recycled glass. This: https://ceramictechchat.ceramics.org/974767/12251109-the-everlasting-relevance-of-brick-john-sanders briefly brings up the possibility of making brick with up to 60% recycled glass.

> I was looking for the trial version of the NIST? phase diagram software ...
Just to point out that there is a time-dimension to phase transforms that phase-diagrams don't capture.
A physicist might say that they are "thermodynamically correct", and only show what phase has the lowest energy under the given conditions. Saying nothing about how long the change of phase will take.
AFAIK it's rarely of practical significance, although I suppose it's relevant when the timing/temperature of the firing becomes important: e.g  slow-cooling microcrystalline glazes, nursing macro-crystalline glazes.

The effect is spectacularly evident  in  the phase diagram of carbon.

Normal temperature and pressure is about 1 bar & 300K. So every diamond you have seen is about 1,000 bar away from a point where it is "stable"  ... and not much closer during the geological time where it was in fairly-near-the-surface rocks.
PS
https://www.whiteflash.com/diamond-education/diamonds-how-do-they-form/

I've been tempted to put in the work and see how the ratio holds up. It would make for good content.

I've been tempted to put in the work and see how the ratio holds up. It would make for good content.

I've been tempted to put in the work and see how the ratio holds up. It would make for good content.

I followed the 10:1 rule from Olsen (firebox : flue size) on a similliar project and found I did not get enough pull with a 9 foot chimney of 81 inches in area. I came to the same conclusion that the exit flue is too small. I liked the idea of a fast fire kiln but in my case there were other issues with the depth of my firebox in relation to the heigth of the kiln.
I haven't got back to it but I'll rebuild with twice the flue size and look more closely to a ground hog deisgn with a low, wide chimney instead of the tall, narrow fast fire design.
Established kilns I've been a part of have run into heat saturation issues atfer too many hours of struggling with what amounted to overloading. I bring this up in repsonse to @Biglou13 as I'm sinscerely curious if your design has the mass to succeed as anything other than a fast fire. I don't mean this as a criticism I only mean to work out what expectations we should have from kilns with less mass.

There is old criticsm of certain aspects of glaze chemstyr as being overly complicated and a bit elitist - the UMF system in particular.
Some of the most sucessful potters I've known grew up on a healthy diet of 'melt and see'.  They wasted some time, energy and materials over time I imagine but we did just fine for our purposes.
There is obvious value in the UMF but please don't let the language muffle your curiosity.
 
 

I'd be tempted to sub out some/all of the epk for Helmar.
Once fiing a foot thick cubes sounds adventurous. I'm a bit nervous at the best of times so for sure I'd be concerned about the time it takes water to escape.
again, I'm sometimes overly cautious so, for me, the additions of  organic/inorganic grog helps to move water along more than anything else. I would not want to be responsible for 'surprises'  below 100c.
 

crushed up and screened soft brick can work nicefly in a flour sifter

I would put some spar in the recipe plus some 200 mesh silica. Although, if this is a one time firing and you haven't tested a woodfire body before I would be inclined to purchase a claybody and wedge in your inclusions. I would ask the people firing the kiln which claybody they recommend and if they are okay with you adding decomposed granite or whatever you are thinking of adding that isn't an organic material.

Chicken grit is usually inorganic,    I use grit as inclusion additions to my clay.  I would sinter the grit prior to  adding to clay.  It’s longer conversation but it’s  known concept, my attempt to emulate Shigaraki clay.  This addition will not lighten the clay body for that I suggest adding sawdust to clay..  be carefull not to use oyster shell grit!!!!      
 
if you search back I have posted a recipe based on dick Lehman 12d clay, which is a take on a jack Troy recipe.   I have fired this clay from underfired to 13 ish.   If you can’t find it I’ll re post recipes here  tomorrow.  This a well tested proven recipie.   The addition of fire clay makes it even more hardy but changes characteristics.
are you saying this once fire  or will you bisquing yor work.   Be careful with any solid ish large pieces. That they absolutely dry before firing!
edit   can’t find  my old post here .
i slightly modified recipe in pictures below  i changed plasticizer and lizella instead of red art 
Modified 12 D (original)
EPK                                 36.8
Nephaline Syenite  24.5
OM4 Ball Clay          14.3
Silica                               19.1
Bentonite                       5.1
Redart                              2.5
Total102.3
variation add 36  ap green fire clay   brown  and will stand up to higher temp (ap green is no longer available) im told other fireclays will work
 

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So in the interest of clarity: 21litres can look a lot like 2 litres to tired eyes
...

So in the interest of clarity: 21litres can look a lot like 2 litres to tired eyes
...

I was trying to duplicate that warning and then remembered I disabled it in the security settings.
The newest entries are no trouble. I copied an old entry and the new cells work fine - problem solved.
 

It's only an issue when I have to re-enter certain recipes and that's really nbd.
I thought maybe if it was an easy fix i could save myself the occasional hassle but I'm only working on the odd project that benefits from EuCal. I'm illiterate when it comes to excel so I'm just thankful to have it.
 

For some of us with lithium problems that's like finding a horde of buried treasure.
iirc 500g @ 120$ was the last restock cost in some parts of north america
 
 

You are not alone here.
At most I'll risk a dip on the rim or pouring swipe of some safe matte for slight changes in texture mostly.
There are many more than two of us keeping metal oxides out of our liner glazes I imagine. The iron in tenmoku is an exception here.  A case can be made for copper too except for the one medical condition - so copper is out.
Opacifiers like tin and titanium are ok so this helps us find more shades of iron. Zircopax can help improve durability apparently and if I remember correctly magnesium helps with glaze fit?
I know 'good glass' will prevent leaching but the cynic in me sees more people concerned with projects other than a sound liner glaze - this includes craze free clears.
As liners, clears are the most difficult in this regard, imo. We don't get to hide behind tenmokus. And even though a properly vitrified clay will forgive some crazing its easier to simply promote a crackle aesthetic than develop and maintain a craze free, clear surface.
My pots might tend towards boring but idc too much. I do tend to overthink things so keeping things simple can help - sometimes.
 
 

You are not alone here.
At most I'll risk a dip on the rim or pouring swipe of some safe matte for slight changes in texture mostly.
There are many more than two of us keeping metal oxides out of our liner glazes I imagine. The iron in tenmoku is an exception here.  A case can be made for copper too except for the one medical condition - so copper is out.
Opacifiers like tin and titanium are ok so this helps us find more shades of iron. Zircopax can help improve durability apparently and if I remember correctly magnesium helps with glaze fit?
I know 'good glass' will prevent leaching but the cynic in me sees more people concerned with projects other than a sound liner glaze - this includes craze free clears.
As liners, clears are the most difficult in this regard, imo. We don't get to hide behind tenmokus. And even though a properly vitrified clay will forgive some crazing its easier to simply promote a crackle aesthetic than develop and maintain a craze free, clear surface.
My pots might tend towards boring but idc too much. I do tend to overthink things so keeping things simple can help - sometimes.
 
 

Clarification on the Glazy post: the image of that glaze on White Bear clay isn’t Joe’s, it’s another contributor using that glaze. The accreditation is in the gallery. Her name is Michelle Smith. https://glazy.org/u/mlsmithsbcglobalnet/recipes

When GB was going extinct the first time I started using Boraq 2  from and it worked just fine for what I was after.  This was ? 2? decades ago?
https://digitalfire.com/recipe/p3998
https://digitalfire.com/material/boraq+2
https://digitalfire.com/material/boraq+3

When GB was going extinct the first time I started using Boraq 2  from and it worked just fine for what I was after.  This was ? 2? decades ago?
https://digitalfire.com/recipe/p3998
https://digitalfire.com/material/boraq+2
https://digitalfire.com/material/boraq+3

One from Glazy below. I have found that with dark glazes it is hard to see crazing, there is a thread here where @Pieter Mostert suggests "Fill the vase with a mixture of vinegar and Whiting (it will bubble) and let it stand overnight. The Whiting and vinegar react to form calcium acetate, which is soluble, so will migrate into the body if it allows water to seep through. After you empty the vase, the calcium acetate will slowly migrate to the surface as the body dries out, and will concentrate along any craze lines." If you try this and it works it would be great if you share your findings here as there isn't much info on this. 
I've also read about Ron Roy accidentally highlighting crazing with steam. Apparently he had a bowl of hot mashed potatoes and the steam from the potatoes showed in the craze lines.  Don't know if it was a matte glaze or not. 
Another thing that helps with testing for crazing on glazes which aren't dark is to use Sumi or calligraphy ink instead of a felt pen. It seems to show crazing better than a felt pen. In the image below the author states they used ink.

this number seems high?
or I'm probably missing something