Dick White

Regarding deflocculating the slip to make it thinner with less water, do not use Darvan. Darvan is a fine deflocculant for many things, but the reaction that causes the starburst effect in mocha diffusion is due to the acidic "tea" vs. the alkaline slip. The slip is already slightly alkaline, so deflocculating with a touch of sodium silicate or soda ash adds to the alkalinity of the slip. Darvan deflocculates by a different mechanism, so may not give the same outcome as the sodium items.

Both the Skutt and L&L kilns have a full-height control column for the digital controller with fiddlie electrical connections to the elements that make it very inconvenient to casually take the sections apart for loading large sculptures. Note also that while both use a 60 amp circuit, the Skutt 1027 kiln is smaller total volume and is rated for cone 10, while the wider L&L e28T is rated to only cone 8 (generally regarded as usable to cone 6 in the long term) because of the greater volume.
You might consider instead the L&L Jupiter series. The individual sections are not hard-wired to the inside back of control panel, but are plug-in to the side of the control panel. There will still be some disassembly needed to take the sections apart, but would be easier than either the Skutt or L&L e-series kilns.

The manufacturer's address on the label is a city, zone, and state, i.e., pre-zipcodes. Zipcodes were implemented by the Post Office in 1963. That gives you a marker for the kiln's age. The electrical rating is 19 amps @ 110V, or about 2000 watts. The apparent size of the kiln plus the low watts of heat suggests it will not go past earthenware temperatures.

And when diving deep into the UMF rabbit hole, several other things become apparent. Boron is not a flux. Fluxes create a eutectic with the silica and alumina to cause them to melt at lower temperatures. Boron is actually a stabilizer (R2O3, like alumina) but melts by itself at such a low temperature that it needs no assistance from a flux. It brings the other oxides into the melt simply because it has already melted. Also, the other fluxes each impart unique properties to the glaze aside from their melty-ness. Lithium is a more powerful flux, but too much messes with expansion (it can both craze and shiver). Shifting the balance of sodium vs. potassium can result in different color responses from some colorants (e.g., copper). So much of glaze chemistry cannot be demonstrated simply by the numbers - experience and testing is how we sort out many of the variables.

And when diving deep into the UMF rabbit hole, several other things become apparent. Boron is not a flux. Fluxes create a eutectic with the silica and alumina to cause them to melt at lower temperatures. Boron is actually a stabilizer (R2O3, like alumina) but melts by itself at such a low temperature that it needs no assistance from a flux. It brings the other oxides into the melt simply because it has already melted. Also, the other fluxes each impart unique properties to the glaze aside from their melty-ness. Lithium is a more powerful flux, but too much messes with expansion (it can both craze and shiver). Shifting the balance of sodium vs. potassium can result in different color responses from some colorants (e.g., copper). So much of glaze chemistry cannot be demonstrated simply by the numbers - experience and testing is how we sort out many of the variables.

To calcine clay (ball or kaolin), just put a big bisqued bowl of it in your next bisque firing. Unlike some other materials that might sinter if calcined to too high of a temperature, clay is refractory and can withstand bisque temperatures, so just use your next bisque firing for calcining it rather than using your propane for firing a single item.

It appears that the pits go all the way through to the body, so the bubbles are starting there. You say the body is rated for cone 5-10. That means it is immature at cone 5/6, not mature until 10. An alleged  wide firing range is one of the unfortunate fallacies perpetrated by the clay industry. My guess is that there is still stuff outgassing from the body at cone 6. If you are using a kiln with a digital controller, you can try a controlled cooling to allow the glaze to heal over any bubbles that are coming up.
As for the unexpected color, I'm not familiar with that glaze.

Often, that clicking sound indicates the bat is not securely fastened to the wheel head because the bat pins are not securely fastened, and both the pin and the bat are wobbling. I lot of potters I have observed believe it is sufficient to just stick a bat pin in the hole and it will solidly stay there. Until it begins to wobble in the hole with the varying pressure on it while centering. Others know that the pin will be loose in the hole and try to accommodate that by wrapping a bit of paper around the pin before shoving it into the hole. Until the paper gets wet and the pin begins to wobble in the hole. The solution is wing nuts to tighten the bat pin to the wheel head from underneath. Wing nuts take some facile finger work to get them started on the pin, and more finger/thumb strength to twist them tight. Sometimes they will work themselves loose and the clicking is the signal to stop and tighten them again.
As for the one oblong hole on the bottom of the bat, note that the oblong dimension is aligned with the radius (diameter) of the bat. That allows one to get the first pin set and still be able to move the bat crosswise to set the other pin. The movement is restricted to across the diameter of the bat, not tangentially around the circumference of the bat. Once set the bat should not move either crosswise (because the hole for the other pin exactly fits) or around the wheel (because the oval hole does not have any tolerance in that direction). Thus, the only  possible movement is a loose pin not firmly tightened against the wheel head.

The OP shows a location in the UK and price limits in pounds. The standard electric service there is 230V. In the US, standard residential electric service is 120/240V, where the normal household receptacle is 120V and other special purpose receptacles are 240V. Thus, in the US, there are a variety of kilns designed for either 120V or 240V service. I don't think there will be any 120V kilns in the UK, but I could be wrong.

The OP shows a location in the UK and price limits in pounds. The standard electric service there is 230V. In the US, standard residential electric service is 120/240V, where the normal household receptacle is 120V and other special purpose receptacles are 240V. Thus, in the US, there are a variety of kilns designed for either 120V or 240V service. I don't think there will be any 120V kilns in the UK, but I could be wrong.

All the time now. Gerstley is gone and Gillespie is not a perfect match. 3134 requires a complete rewrite of the recipe. Custer is gone from the market, but I still have some. G200EU might be ok, haven’t tried it yet. Still have some old Amtal talc, but some Fabi is in my future. What’s next?

All the time now. Gerstley is gone and Gillespie is not a perfect match. 3134 requires a complete rewrite of the recipe. Custer is gone from the market, but I still have some. G200EU might be ok, haven’t tried it yet. Still have some old Amtal talc, but some Fabi is in my future. What’s next?

All the time now. Gerstley is gone and Gillespie is not a perfect match. 3134 requires a complete rewrite of the recipe. Custer is gone from the market, but I still have some. G200EU might be ok, haven’t tried it yet. Still have some old Amtal talc, but some Fabi is in my future. What’s next?

At 800 degrees, the glaze particles have not begun to sinter, they are just a little toasty. Fix the kiln and refire.

At 800 degrees, the glaze particles have not begun to sinter, they are just a little toasty. Fix the kiln and refire.

At 800 degrees, the glaze particles have not begun to sinter, they are just a little toasty. Fix the kiln and refire.

At 800 degrees, the glaze particles have not begun to sinter, they are just a little toasty. Fix the kiln and refire.

As others have already noted, neither zinc oxide nor chrome oxide used in reasonable amounts in a stable glaze are toxic. A different issue arises when both are used together in the same glaze - ugliness abounds. Chrome is supposed to be green when in a glaze that does not contain tin. A combination with tin in the right amounts creates a variety of pinks and reds. Zinc with chrome, however, turns assorted shades of brown, when copious amounts are used. It won't hurt you, but you probably don't want to look at it. Perhaps your glaze recipe doesn't have enough for the adverse color reactions.

As others have already noted, neither zinc oxide nor chrome oxide used in reasonable amounts in a stable glaze are toxic. A different issue arises when both are used together in the same glaze - ugliness abounds. Chrome is supposed to be green when in a glaze that does not contain tin. A combination with tin in the right amounts creates a variety of pinks and reds. Zinc with chrome, however, turns assorted shades of brown, when copious amounts are used. It won't hurt you, but you probably don't want to look at it. Perhaps your glaze recipe doesn't have enough for the adverse color reactions.

As others have already noted, neither zinc oxide nor chrome oxide used in reasonable amounts in a stable glaze are toxic. A different issue arises when both are used together in the same glaze - ugliness abounds. Chrome is supposed to be green when in a glaze that does not contain tin. A combination with tin in the right amounts creates a variety of pinks and reds. Zinc with chrome, however, turns assorted shades of brown, when copious amounts are used. It won't hurt you, but you probably don't want to look at it. Perhaps your glaze recipe doesn't have enough for the adverse color reactions.

As others have already noted, neither zinc oxide nor chrome oxide used in reasonable amounts in a stable glaze are toxic. A different issue arises when both are used together in the same glaze - ugliness abounds. Chrome is supposed to be green when in a glaze that does not contain tin. A combination with tin in the right amounts creates a variety of pinks and reds. Zinc with chrome, however, turns assorted shades of brown, when copious amounts are used. It won't hurt you, but you probably don't want to look at it. Perhaps your glaze recipe doesn't have enough for the adverse color reactions.

As others have already noted, neither zinc oxide nor chrome oxide used in reasonable amounts in a stable glaze are toxic. A different issue arises when both are used together in the same glaze - ugliness abounds. Chrome is supposed to be green when in a glaze that does not contain tin. A combination with tin in the right amounts creates a variety of pinks and reds. Zinc with chrome, however, turns assorted shades of brown, when copious amounts are used. It won't hurt you, but you probably don't want to look at it. Perhaps your glaze recipe doesn't have enough for the adverse color reactions.

The Sentry FTH error is similar to the Bartlett E1, in that both are in response to the controller detecting the temperature not rising as expected according to the program. The difference is that the Sentry continues to fire, albeit slowly, until the target temperature is finally reached, whereas the Bartlett error will terminate the firing.

The Sentry FTH error is similar to the Bartlett E1, in that both are in response to the controller detecting the temperature not rising as expected according to the program. The difference is that the Sentry continues to fire, albeit slowly, until the target temperature is finally reached, whereas the Bartlett error will terminate the firing.

No, it does not warp. In my experience, Hardibacker brand is the best of the several available brands. Be aware that there are 3 types of Hardibacker - one is 1/4" thick and two are 1/2" thick. Of the two that are 1/2" thick, one is the original Hardibacker which is somewhat absorbent but is not degraded by the moisture; and the other is a new super non-absorbent type. It can be distinguished from the original type both by price (it's more expensive per sheet) and one side of it is lightly sprayed with a red "paint." Get the original for its absorbency, not the red one. The 1/4" stock is also the original type, so choose the thickness that suits your intended usage.