Dick White

There is another theory about pinholes in commercial brushing glazes that is not widely discussed. That theory holds that when the first coat of glaze is brushed on, there are likely to be some small voids in the coating that are nearly unnoticeable. When the second coat is applied, it doesn't get down in these little voids, creating air bubbles where the second (and later coats) cover them up. Late in the firing, the melt finally gets down to that layer, and the bubbles erupt out through the glaze. Just an idea. If you don't have trouble with this clay body pinholing with dipping glazes, you probably can eliminate the body as the problem and look towards your brush application.

There is another theory about pinholes in commercial brushing glazes that is not widely discussed. That theory holds that when the first coat of glaze is brushed on, there are likely to be some small voids in the coating that are nearly unnoticeable. When the second coat is applied, it doesn't get down in these little voids, creating air bubbles where the second (and later coats) cover them up. Late in the firing, the melt finally gets down to that layer, and the bubbles erupt out through the glaze. Just an idea. If you don't have trouble with this clay body pinholing with dipping glazes, you probably can eliminate the body as the problem and look towards your brush application.

There is another theory about pinholes in commercial brushing glazes that is not widely discussed. That theory holds that when the first coat of glaze is brushed on, there are likely to be some small voids in the coating that are nearly unnoticeable. When the second coat is applied, it doesn't get down in these little voids, creating air bubbles where the second (and later coats) cover them up. Late in the firing, the melt finally gets down to that layer, and the bubbles erupt out through the glaze. Just an idea. If you don't have trouble with this clay body pinholing with dipping glazes, you probably can eliminate the body as the problem and look towards your brush application.

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.

Yes, always connect the green (or bare) ground wire to the ground lug of either plug or receptacle, so that the case is grounded at all times.

Back in the day, dryers (with a 10-30 plug) and stoves (with a 10-50 plug) used 240V from the two hots for the heating circuits while the controls and interior lights used 120V from one of the hots plus the neutral. Apparently, independent grounding wasn't a high priority back then for those household appliances as chassis grounding was permitted through the neutral, though the  really old120/240V kilns that we sometimes get involved with here all use proper 4-wire grounded circuits. In '96, the code changed to mandate separate grounding everywhere, hence the change to 14-30 and 14-50 for all new dryer and stove circuits. There is still a neutral for any 120V components in the dryers or stoves, but now there is a separate safety ground. However, you can still get a 10-30 cord for a new dryer if you are installing it in a grandfathered pre-'96 house.
I too suspect it is unlikely that this kiln has anything in it running on 120V (that would need the neutral), and therefore should be fine with a fresh 6-50 power cord, with the circuit in/on the wall running a straight double 240V 40A breaker and 8 /2-with ground cable to a 6-50R outlet. 

The island/mound will occur when the proper amount of dry plaster has been added to the water in an appropriate size and shape bucket. However, an island/mound may also occur with the incorrect amount of plaster and /or an inappropriate size or shape bucket, and so the mere appearance of this infamous island/mound should not be regarded as the proper mixing ratio. The only accurate method to get a strong plaster mold is to add the exact weight of plaster to the exact quantity of water as specified by the plaster manufacturer. The ratio of plaster to water is different for plaster of paris vs. pottery #1 plaster.

The island/mound will occur when the proper amount of dry plaster has been added to the water in an appropriate size and shape bucket. However, an island/mound may also occur with the incorrect amount of plaster and /or an inappropriate size or shape bucket, and so the mere appearance of this infamous island/mound should not be regarded as the proper mixing ratio. The only accurate method to get a strong plaster mold is to add the exact weight of plaster to the exact quantity of water as specified by the plaster manufacturer. The ratio of plaster to water is different for plaster of paris vs. pottery #1 plaster.

The island/mound will occur when the proper amount of dry plaster has been added to the water in an appropriate size and shape bucket. However, an island/mound may also occur with the incorrect amount of plaster and /or an inappropriate size or shape bucket, and so the mere appearance of this infamous island/mound should not be regarded as the proper mixing ratio. The only accurate method to get a strong plaster mold is to add the exact weight of plaster to the exact quantity of water as specified by the plaster manufacturer. The ratio of plaster to water is different for plaster of paris vs. pottery #1 plaster.

The island/mound will occur when the proper amount of dry plaster has been added to the water in an appropriate size and shape bucket. However, an island/mound may also occur with the incorrect amount of plaster and /or an inappropriate size or shape bucket, and so the mere appearance of this infamous island/mound should not be regarded as the proper mixing ratio. The only accurate method to get a strong plaster mold is to add the exact weight of plaster to the exact quantity of water as specified by the plaster manufacturer. The ratio of plaster to water is different for plaster of paris vs. pottery #1 plaster.

Many studios use plastic dry cleaner bags to wrap the fresh greenware. I have not been in a dry cleaner establishment in the 15 years since I retired from my real day job downtown, so I ask students to bring in theirs. One studio I work with went to whatever supply house and got a full 1000 piece roll just like the cleaners use; we've been working that roll for 4 years and still have half. The dry cleaner bags seem to have a reasonably predictable permeability for drying by next class time, and they are thin, light, and flexible so the ware is not smushed when wrapping it. The problem is that few students take the time to cut the full bag into appropriate size pieces, so the work-in-progress ware shelves are loaded with single mugs on 12" square boards wrapped in an entire bag (and because it is still a bag, it's a double layer draped over the mug). And then some Helpful Hanna/Harry brings in an armful of garment bags scavenged from the department store when the stock clerk was unwrapping and setting out the spring fashions - a completely different type and weight of plastic. And don't get me started on the empty clay bags that show up in the bin. After all, plastic is plastic, isn't it? Well, no, as you point out there is plastic and there is *plastic*, not all the same.
All that said, when the bin is running low (with 125 students cranking out production), I have picked up a package of cheap lightweight painter's drop cloth from the local blue or orange big box, like your suggestion (except I get the lightweight 3-pack, yours is midweight). I've also noticed that the community center uses the cheapest lightest thinnest trash bags, so I have raided the janitor closet.
Carry on, we are comrades in arms...

... another link from the Paragon website. Paragon bought the Duncan line when they went out of business. https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/LX851_Duncan_Energy_Saver_Owner_Manual.pdf
dw

... another link from the Paragon website. Paragon bought the Duncan line when they went out of business. https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/LX851_Duncan_Energy_Saver_Owner_Manual.pdf
dw

If you're sure it's 2.5" brick, then are you sure it's a KM1227? Skutt doesn't make the 1227 with 2.5" brick. Is it a 1027?

There are several issues in play here. First, about cone numbers - if you download a cone chart from this link https://www.ortonceramic.com/files/2676/File/Orton-Cone-Chart-F-022-14.pdf you will see the temperature/rates for every cone. Note that there is no cone 0, and cone numbers from 01 and up are actually running backwards, the temperatures getting colder as the number gets higher; cone numbers without a O in front of the number run as you would expect, the temperatures increase as the number gets higher. Thus, your array of cones 04, 5, and 6 do not relate to each other. There is 200+℉ difference between 04 and 5, which is why the 5 and 6 cones are unmoved when fired to 04. Cones above 3 are different colors in the box so you can easily tell them apart when loading the kiln, but the dye burns out during the firing, leaving them white. 
Second, about the accuracy of programmable kilns - they are not accurate out of the box. More often than not, they tend to fire hotter than the nominal temperature shown on the screen. The reported maximum temperature will correlate correctly to the Orton cone table linked above, meaning that the final temperature attained at slow speed will be lower than the temperature reported for medium speed, and higher yet for fast speed. That's just the way cones work - the bending process takes time as well as temperature to penetrate to the center of the cone (and the center of a ceramic piece). But back to the kiln accuracy - if the kiln is firing hotter or cooler than the cone bend, you can calibrate the controller to, in effect, fool it to add or subtract a certain number of degrees to what the thermocouple seems to be reporting, and thus adjust the actual results so that cone 5 (let's say) on the screen properly bends cone 5 inside the kiln. If you have never played with the controller adjustments, you should call Skutt and ask one of the technical reps to walk you through the process.

There are several issues in play here. First, about cone numbers - if you download a cone chart from this link https://www.ortonceramic.com/files/2676/File/Orton-Cone-Chart-F-022-14.pdf you will see the temperature/rates for every cone. Note that there is no cone 0, and cone numbers from 01 and up are actually running backwards, the temperatures getting colder as the number gets higher; cone numbers without a O in front of the number run as you would expect, the temperatures increase as the number gets higher. Thus, your array of cones 04, 5, and 6 do not relate to each other. There is 200+℉ difference between 04 and 5, which is why the 5 and 6 cones are unmoved when fired to 04. Cones above 3 are different colors in the box so you can easily tell them apart when loading the kiln, but the dye burns out during the firing, leaving them white. 
Second, about the accuracy of programmable kilns - they are not accurate out of the box. More often than not, they tend to fire hotter than the nominal temperature shown on the screen. The reported maximum temperature will correlate correctly to the Orton cone table linked above, meaning that the final temperature attained at slow speed will be lower than the temperature reported for medium speed, and higher yet for fast speed. That's just the way cones work - the bending process takes time as well as temperature to penetrate to the center of the cone (and the center of a ceramic piece). But back to the kiln accuracy - if the kiln is firing hotter or cooler than the cone bend, you can calibrate the controller to, in effect, fool it to add or subtract a certain number of degrees to what the thermocouple seems to be reporting, and thus adjust the actual results so that cone 5 (let's say) on the screen properly bends cone 5 inside the kiln. If you have never played with the controller adjustments, you should call Skutt and ask one of the technical reps to walk you through the process.

There are several issues in play here. First, about cone numbers - if you download a cone chart from this link https://www.ortonceramic.com/files/2676/File/Orton-Cone-Chart-F-022-14.pdf you will see the temperature/rates for every cone. Note that there is no cone 0, and cone numbers from 01 and up are actually running backwards, the temperatures getting colder as the number gets higher; cone numbers without a O in front of the number run as you would expect, the temperatures increase as the number gets higher. Thus, your array of cones 04, 5, and 6 do not relate to each other. There is 200+℉ difference between 04 and 5, which is why the 5 and 6 cones are unmoved when fired to 04. Cones above 3 are different colors in the box so you can easily tell them apart when loading the kiln, but the dye burns out during the firing, leaving them white. 
Second, about the accuracy of programmable kilns - they are not accurate out of the box. More often than not, they tend to fire hotter than the nominal temperature shown on the screen. The reported maximum temperature will correlate correctly to the Orton cone table linked above, meaning that the final temperature attained at slow speed will be lower than the temperature reported for medium speed, and higher yet for fast speed. That's just the way cones work - the bending process takes time as well as temperature to penetrate to the center of the cone (and the center of a ceramic piece). But back to the kiln accuracy - if the kiln is firing hotter or cooler than the cone bend, you can calibrate the controller to, in effect, fool it to add or subtract a certain number of degrees to what the thermocouple seems to be reporting, and thus adjust the actual results so that cone 5 (let's say) on the screen properly bends cone 5 inside the kiln. If you have never played with the controller adjustments, you should call Skutt and ask one of the technical reps to walk you through the process.

Put a single layer of Saran Wrap or similar thin plastic film over the silver bowl to protect it from possible chemical reactions with something in the clay. It is probable that nothing untoward would happen with the clay in the bowl, but don't take the chance on the unknown.

Put a single layer of Saran Wrap or similar thin plastic film over the silver bowl to protect it from possible chemical reactions with something in the clay. It is probable that nothing untoward would happen with the clay in the bowl, but don't take the chance on the unknown.

Well, actually, the elements in those wiring diagrams are in series. There are 4 separate elements total, 2 in each of the sections. To measure the resistance of each section, apply the multimeter probes at the power inputs to the elements. The resistance will be the sum of the two individual elements. For example, in the B18 diagram, each section has two elements of 10.2 ohms each, which should measure as 20.4 ohms across the power leads. Thus using an Ohms Law calculator, that section running at 240V will draw 11.7 amps. Doubling that for both the top and bottom sections yields 23 amps total, which is slightly more than the stated 22 amps, but close enough to allow for some slippage and wear. Continuing the example for the 23H model, each section has a 7.8 ohm and 6.6 ohm element in series, for a measured total of 14.4 ohms across the power leads to the elements of that section.  At the specified 208V, each section is drawing 14.4 amps, which doubled for both sections of the kiln yields total amperage of 28.8 amps, which rounds to the specified 29 amps.
You correctly note that some kilns  have elements with different resistances. The B23 drawing you found is an example of that. In the top section, the element closest to the top is 7.8 ohms and the one in the middle is 6.6 ohms. The bottom section is the reverse, with the 7.8 ohm element closest to the base and the 6.6 ohm one in the middle. You say the Cress rep told you the top and bottom elements are 9.2 ohms. If we assume that your B23 is also rated as 29 amps total but at 240V (confirm that on the electrical rating plate on your kiln, I am just guessing here), then the amperage per each top and bottom section will be ~14.5 amps, which calculates to a resistance of ~16.5 ohms total for the two elements in series in the section. If one is supposed to be 9.2 ohms, the other must be 7.3 ohms.
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Put a single layer of Saran Wrap or similar thin plastic film over the silver bowl to protect it from possible chemical reactions with something in the clay. It is probable that nothing untoward would happen with the clay in the bowl, but don't take the chance on the unknown.

Some feldspar history... G200 was a potash feldspar mined in Monticello, Georgia, but the ore was higher in potassium than other comparable potash feldspars, such as Custer. To resolve this difference, they blended it 70:30 with a soda feldspar brought in from a mine in Spruce Pine, North Carolina. About 15 years ago, the bean counters decided that trucking soda feldspar 300 miles to just to mix it with another feldspar was not economical, so they stopped that. The plain potash feldspar from the Monticello mine was relabeled as G200HP (for High Potassium) and the ceramic industry was advised to mix their own if we wanted to replicate the old G200. Some of us did, some of us bought a product blended by Lauguna and marketed as Old Blend, and others of us moved on to other brands of potash feldspar. About 10 years ago, the Monticello mine was exhausted, and G200HP is no more. The Imerys Corporation (which now owned the mine and product) found a potash feldspar similar to the old blended  product (and other potash feldspars) in Spain and began importing it as G200EU.
So, to answer your specific question - no, you can't buy G200HP anymore (but I know someone who has some). There is nothing else like it on the market that has that high level of potassium. I don't know if you can trust the label of what you just got as actually the old blended G200 that has not been widely available for a long time or maybe is the Spanish G200EU. Because of these nuances, using another brand of feldspar with your remaining G200HP or in place of it is likely to change the way your G200HP recipes turn out. Or you can take a deep dive into some glaze chem software and sort it out from there.

Some feldspar history... G200 was a potash feldspar mined in Monticello, Georgia, but the ore was higher in potassium than other comparable potash feldspars, such as Custer. To resolve this difference, they blended it 70:30 with a soda feldspar brought in from a mine in Spruce Pine, North Carolina. About 15 years ago, the bean counters decided that trucking soda feldspar 300 miles to just to mix it with another feldspar was not economical, so they stopped that. The plain potash feldspar from the Monticello mine was relabeled as G200HP (for High Potassium) and the ceramic industry was advised to mix their own if we wanted to replicate the old G200. Some of us did, some of us bought a product blended by Lauguna and marketed as Old Blend, and others of us moved on to other brands of potash feldspar. About 10 years ago, the Monticello mine was exhausted, and G200HP is no more. The Imerys Corporation (which now owned the mine and product) found a potash feldspar similar to the old blended  product (and other potash feldspars) in Spain and began importing it as G200EU.
So, to answer your specific question - no, you can't buy G200HP anymore (but I know someone who has some). There is nothing else like it on the market that has that high level of potassium. I don't know if you can trust the label of what you just got as actually the old blended G200 that has not been widely available for a long time or maybe is the Spanish G200EU. Because of these nuances, using another brand of feldspar with your remaining G200HP or in place of it is likely to change the way your G200HP recipes turn out. Or you can take a deep dive into some glaze chem software and sort it out from there.

Yes, no, maybe. We have no clue what colorants or what amounts of said colorants are in commercial underglazes. As for Mason stains (i.e., Mason brand), they do publish a reference document showing what colorants are in each stain number, but not amounts. Of the 5 black stains, 6600 and 6612 are listed as compatible with either zinc-free or zinc-contain glaze. The others, 6650, 6657, and 6666, specifically state zinc-free glaze needed. The issue is that zinc and chrome do not play well together. About 75% of the Mason stains have some chrome in the mix of colorants, so a zinc-containing glaze will alter the intended color of the stain. Hence, zinc-free being the go-to recommendation, especially for underglazes for which there is no public data.

Yes, no, maybe. We have no clue what colorants or what amounts of said colorants are in commercial underglazes. As for Mason stains (i.e., Mason brand), they do publish a reference document showing what colorants are in each stain number, but not amounts. Of the 5 black stains, 6600 and 6612 are listed as compatible with either zinc-free or zinc-contain glaze. The others, 6650, 6657, and 6666, specifically state zinc-free glaze needed. The issue is that zinc and chrome do not play well together. About 75% of the Mason stains have some chrome in the mix of colorants, so a zinc-containing glaze will alter the intended color of the stain. Hence, zinc-free being the go-to recommendation, especially for underglazes for which there is no public data.