PeterH

Years ago I moved from a soft water area (Liverpool) to a hard water area (Essex), and my skin stopped wrinkling when I had a long baths.  (Also I needed to use more soap, as hard water reduces its effectiveness.)
A suggestion that the effects of moving  from hard water to soft may be self-correcting over time.
https://kidshealth.org/en/kids/wrinkly-fingers.html
I suppose you might try experimenting with:
- pre-exposure skin/barrier creams
- slightly hardening the water you use for throwing (slightly because it may effect the clay)
https://sciencing.com/make-hard-water-8191733.html
https://www.usgs.gov/special-topics/water-science-school/science/hardness-water
General guidelines for classification of waters are: 0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard.

Atlanta refs to confirm your suspicions about water hardness.
https://www.atlantisplumbing.com/articles/city-water-vs-well-water/
City Water Vs. Well Water
2. Generally speaking, well water is hard water so a water softener is recommended for homes that use well water.
https://www.hydroflow-usa.com/georgia-water-hardness
Georgia water is considered soft water. The average water hardness for the Georgia resident is around 60 PPM. Atlanta, the most populous Georgia city has a water hardness level of 21 PPM which according to USGS water hardness measures is very soft.
PS In this context mg/L = mg/kg = PPM

My first impression that it's not a normal  crack pattern, which are often well described by
Hierarchical crack pattern as formed by successive domain divisions Pt 1
https://www.researchgate.net/publication/235540544_Hierarchical_crack_pattern_as_formed_by_successive_domain_divisions_I_Temporal_and_geometrical_hierarchy

Which seem to have a family resemblance to many crackle glazes, and this crackle slip
https://glazy.org/recipes/56903

... which isn't looking too like Aneta Regel's work to me.

Perhaps this is because there are "large" grains inside the shrinking "slip", causing both local "hot-spots" in the tension and impeding the free propogation of the crack within the mixture.

Is the video you mention the Ceramic Review ""masterclass"?
The accompanying article is at
https://www.ceramicreview.com/articles/material-beauty-2/
PS A couple of quotes I found interesting.
https://tlmagazine.com/nomad-vibrant-colours-and-playfulness/
Stone (both presented and represented in her work) makes an important contribution to the materiality of Regel’s artistic practice. Her technique of mixing porcelain with gravel, placing stones into the clay, and subsequently allowing the clay to shrink and crack around the rock inside the kiln makes for a sensational sort of indeterminacy as the artwork rises to the challenge of forming and reforming itself.
https://artsandculture.google.com/asset/raining-stones-aneta-regel/xAGlSpRuwPcv-g

 
 

Yes and no.  It all depends upon how the model was treated.
As Peter suggests "waste molds" are really only intended to be one time objects. However, sometimes they are so labor intensive that you just want to use it to make a test piece. (To see if it works.) 
Did you have to use lots of mold sealer to make the waste mold? (in other words, is the waste mold really "dirty" from the making process?) 
There have been many times that I have used a waste mold to make a test casting. However, I accepted the fact that it might not turn out, as expected, and it was "just a test".
ps. if the mold parts are "dirty" washing them will help and waiting for them to dry is a good lesson in self-discipline.

Is the video you mention the Ceramic Review ""masterclass"?
The accompanying article is at
https://www.ceramicreview.com/articles/material-beauty-2/
PS A couple of quotes I found interesting.
https://tlmagazine.com/nomad-vibrant-colours-and-playfulness/
Stone (both presented and represented in her work) makes an important contribution to the materiality of Regel’s artistic practice. Her technique of mixing porcelain with gravel, placing stones into the clay, and subsequently allowing the clay to shrink and crack around the rock inside the kiln makes for a sensational sort of indeterminacy as the artwork rises to the challenge of forming and reforming itself.
https://artsandculture.google.com/asset/raining-stones-aneta-regel/xAGlSpRuwPcv-g

 
 

Is the video you mention the Ceramic Review ""masterclass"?
The accompanying article is at
https://www.ceramicreview.com/articles/material-beauty-2/
PS A couple of quotes I found interesting.
https://tlmagazine.com/nomad-vibrant-colours-and-playfulness/
Stone (both presented and represented in her work) makes an important contribution to the materiality of Regel’s artistic practice. Her technique of mixing porcelain with gravel, placing stones into the clay, and subsequently allowing the clay to shrink and crack around the rock inside the kiln makes for a sensational sort of indeterminacy as the artwork rises to the challenge of forming and reforming itself.
https://artsandculture.google.com/asset/raining-stones-aneta-regel/xAGlSpRuwPcv-g

 
 

if its just been bisqued bisfix will work fine for this. See above video
There are other menders that work as well like Marks mender and highfire mender for glaze wares-I have used them all

Bisque Fix?
 

I know zilch about wheels, but loud pops can be caused by an electrolytic capacitor blowing.
Can you post a picture of the component side of the circuit board?

Bisque Fix?
 

I know zilch about wheels, but loud pops can be caused by an electrolytic capacitor blowing.
Can you post a picture of the component side of the circuit board?

+1 drying between wall-board.
In my limited tile-making efforts I also turned the slab+boards over from time.
Re the use of silica sand, I found this a powerful analogy.
PS I was taught that non-optimum rolling can make the slab more likely to warp: frequent turning & unsticking from the rolling surface, gradual reduction in thickness, rolling in multiple directions, don't let any thickness guides constrain the slab's edges, ....

Thanks to you knowledgeable folk my little kiln is now happily ramping up at sonic speed again.  It was indeed damp!!  I propped the lid (which was only possible as I bypassed the lid safety - @High Bridge Pottery (which is the silver box with the cable tied wires) and then I stuck my heat gun nozzle in the bung hole - it fitted perfectly!  Ran it a few times for 5 minutes and each time I lifted the lid tiny little steam clouds puffed out!!! 
 
I am so relieved I don’t have to explore the RCD or current leakage issue just yet!  But fyi my cooker has its own dedicated fuse but it’s still protected by the RCD. 
now I’m debating if I should hook up the lid switch or leave it out as I quite like the idea of propping the lid to reduce the speed the kiln heats up but I do t like the idea of accidentally touching the elements when the kilns power is on…….  i guess I would only make that mistake once…… 
I will never leave the lid open or off for anything (other than loading and unloading) ever again!  
 
thanks again everyone 

 

A few examples from the net:

How to Make a Clay Cylinder - Ceramics Handbuilding for Beginners - YouTube
Making a Clay Cylinder - YouTube
... and the three-part
How I hand build clay cylinders. Part 1 Pottery ceramics techniques - YouTube
How I handbuild clay cylinders Part 2. Removing the cylinder from the former. Handbuilt ceramics - YouTube
How I handbuild clay cylinders. Part 3 Attaching the base - YouTube
... where the cylinder is worked on while on a former

Note that a suitable diameter plastic pipe makes a good former being non-absorbent, smooth &  strong.

Any idea of the manufacturers code for this item?
For example looking through
https://img1.wsimg.com/blobby/go/a473195b-32be-4831-aad8-e122a50bcf46/IN THE KILN CERAMIC GREENWARE-BISQUE LIST.pdf
gives

... but I failed to find more details on the site.
Searching for 183F elsewhere give:
https://bisquebusters.com/products/scenery-mountain-train-3pc

A more general search found this, but without a manufacturers code
https://www.ebay.co.uk/itm/134018515130

It looks like this URL may show both sides of one of the 3 parts of 183F
https://www.ebay.co.uk/itm/134337508508

+1 drying between wall-board.
In my limited tile-making efforts I also turned the slab+boards over from time.
Re the use of silica sand, I found this a powerful analogy.
PS I was taught that non-optimum rolling can make the slab more likely to warp: frequent turning & unsticking from the rolling surface, gradual reduction in thickness, rolling in multiple directions, don't let any thickness guides constrain the slab's edges, ....

When I enter the MC6G High Calcium Matte 2 into the EU calculator I'm not seeing excess to the eutectics of CaO even though this is coming in at 0.90 in the UMF.  I'm going to assume this glaze uses a different matting mechanism, perhaps the excess alumina and silica causing the matting or a micro rippled surface. If that's the case we need another recipe to test the theory with or reduce the silica and alumina perhaps. 

 

I'll plunk it in and see what it shows. If the EU calc shows excess silica (like I assume it would) then yes. 
edit: I'll use this recipe to play around with. (without any colourants)

To give nuance to Peter's suggestions:
The big key is to stretch the clay in lots of directions while you're rolling it out. Will you be making the slab on a slab roller or doing it free hand? If doing it free hand you will want to use various thicknesses of wood sticks to guide you in reducing the thickness. Plop down sticks that are 1" thick and roll the slab. Then pick up the slab, turn it over, spin it 45 degrees. Then roll it with the 3/4" sticks. Pick it up, turn it over, and spin it 45 degrees again. Then plop down the 1/2" sticks, roll the slab again.
Rotating and flipping is the best way to minimize warpage on big slabs. If the clay is too wet you can sometimes stretch it too much at the corners, when you pick it up, so its best to let the clay stiffen a bit between rolls.
Firing the slab is another challenge: are the kiln shelves flat? Is it worth it to go out and buy new shelves that are perfectly flat for the project? (Sometimes it is.) All the silica in the world won't help if the kiln shelf is warped. (Yes, a bed of silica can mitigate a warped shelf but a not warped shelf is the better place to start.)
Clay intended for throwing is considered "plastic". That usually involves shrinkage. Hand building clays tend not to have so much plastic clays in them. Meaning...less shrinkage. Making a large slab is usually best with a hand building clay.
The drywall trick does work well. In place of it several sheets of newspaper, under weight of a flat piece of wood, also reduce warpage in drying.
 

+1 drying between wall-board.
In my limited tile-making efforts I also turned the slab+boards over from time.
Re the use of silica sand, I found this a powerful analogy.
PS I was taught that non-optimum rolling can make the slab more likely to warp: frequent turning & unsticking from the rolling surface, gradual reduction in thickness, rolling in multiple directions, don't let any thickness guides constrain the slab's edges, ....

Bein' curious, and settled down for a late afternoon snooze*, taking a minute to look for that...
...found a scanned version of Hopper's book. The piece is "Trifoot Plate - Southwest Series."
Searching that string, found on Hopper's blog the same/similar image, captioned thus:
"RH - TRIFOOT PLATE - SOUTHWEST SERIES.
THIS EXAMPLE SHOWS CONTROLLED LOCALIZED FUMING OF CHROMIUM RED GLAZE ON TOP OF TIN-OPACIFIED TERRA SIGILLATA"
Here: PHOENIX: BRUSHSTUFF #1 (rhrising.blogspot.com)
Sorry about the all caps, that's a direct copy/past (quotes added, of quote!).
 
*Had appointment this a.m. (6:30 !!) with the specialist for a root canal.
Yep, time for a nap!

@PeterH Looks like masking and looks like the shadowing may have been airbrushed underglaze. That’s what strikes me

there is a new edition out which is much cheaper.

> 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/