PeterH

The "higher heat" idea was explored in this thread
... but I wouldn't be surprised if your problem was related to differences in inside and outside glaze application.

"Is it correct to say that if a glaze/clay combination does not craze at cone 5, then it should not craze at a higher cone firing?"
Good question.
imo, maybe!
"Maybe" on account of the crazing or not crazing may not matter so much if the clay isn't fully mature or is over fired.
For clays that take a higher cone without misbehaving, yes.

In my experience (limited, of course!), some clays have a wider firing range, while others are very much more sensitive to over firing.
Three clays, in particular - a red, buff, and a black clay - that I've tried matured at a solid cone 5 but misbehaved when fired into the top of cone 6 range.
"Fully mature" - where the clay is dense, strong, and has low absorbency*, err, as low as the particular clay can reasonably get, that is.
"Over fired" - where clay has begun to slump/melt, bloat, fizz/bubble...
This article This amazing difference 45 micron silica can make (digitalfire.com) got me thinking.
I wonder if my glaze fitting struggles were related to 200 mesh silica (which is what I have)?
If so, then, would more heat work help dissolve the silica?
If so, then, would more and/or more aggressive fluxes help dissolve the silica?
If so, would a drop & hold (after peak temp) help dissolve the silica?
I don't know.
The solution involved tweaking the formula to reduce COE, however, I'd adopted drop & hold at about the same time.
I'd like to have clay and glaze combinations that can take a half cone or more of "excess" heat work without problems.
The aforementioned sensitive clays, I've found other red and buff clays (haven't tried any other black clays yet).
Keep on with cone packs on each level, keep notes, and test (test, test)!
*article on maturity Maturity (digitalfire.com)
 

+1
There are also some very useful sites on the web, e.g.  https://digitalfire.com
Just picking up on your reference to lead (and I agree it's best not used).
"Safe" a somewhat conditional term.
- The magnificent lead-glazed wall tiles that were still around in older buildings in the 60's would still - IMHO- be quite safe. (Hard to misuse on a dry vertical surface subject to minimal contact.)
- OTOH  I remember reading of a lead glazed milk jug (which was probably quite safe to use for milk). But the owners squeezed orange juice into it every evening and left it in the fridge overnight to serve with breakfast!  Definitely risky. But how do you know what your friends/customers are going to do with your pots? 
Some craft potters choose to use "liner" glazes for surfaces likely to come into contact with food.
https://digitalfire.com/glossary/liner+glaze
Liner-glazing is a very good way to assure that your ware has a durable and leach resistant surface. It also signals customers that you care about this.
https://digitalfire.com/glossary/lead+in+ceramic+glazes
Lead is a melter in ceramic glazes and performs exceptionally well and must be misused to be toxic. It is also now environmentally pervasive. It is toxic and cumulative at any level of exposure.
... and had a history of frequent misuse, hence the [slightly over] reaction to its use.

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

If by waste mold you mean a sculptor's mold that cannot be removed from the casting without being destroyed ...
I think the answer has to be no, as the fragile casting would not survive any process that required the the mold to be destroyed to free it.
It may be possible to make a reusable multi-part slip-casting mold from the original clay master. If this can be done without undercuts which would prevent freeing the casting from the mold.
>The thing is that i have a larger sculpture ...
... although large slip-filled molds are heavy and must retain their form during man-handling: e.g. use of natches for registration, holding things firmly together with straps, ...

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

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

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

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, ....