Min

thank you all for answers, after all, it was a soap problem i thought it was dry, but in some ways it sealed surface, solved using a wet sponge cleaning the surface! it works well
giorgio

Here are the bowls fired to electric cone 10 with a semitransparent blue glaze

Hi and welcome to the forum!
Could you post a picture of the blowouts? Also, where in the kiln were the large bowls were in relation to spyholes?

Maybe somebody who has okay correspondence with him could email him on your behalf Morgan?
I'm sorry for your experience.

I've got an altered cone 1-3 glaze from Charlie Cummings who came up with it from Linda Arbuckles glazes. 
Given the variability of materials and firing conditions if you try it please just try a small test amount first. 
Cone 1-3 Majolica White
Gerstley Borate 10.30
Nepheline Syenite 8
EPK 5.6
OM4 Ball clay 4.5
Whiting 9.75
Silic 24
Ferro Frit 3124 37.5
Zircopax 12
The alumina in your glaze is really quite high for a lowfire glaze, it's probably why you aren't getting a good melt. (alumina stiffens a glaze)
 
 
 

As Kelly said, options for having absolutely nothing to worry about in a well balanced stable glaze would be either zero colourants or just zircopax or iron.
If you want to use a stain or a colouring oxide and want to ensure it’s safe then lab testing isn’t going to break the bank. It’s about $35 per oxide to get tested and piece of mind.
BSC testing link https://bsclab.com/pottery-testing
Home testing, using an acid such as household vinegar or lemon/lime and dishwasher testing  don’t rule a glaze “in” as being suitable for food surfaces but it will rule glazes out.

I've got an altered cone 1-3 glaze from Charlie Cummings who came up with it from Linda Arbuckles glazes. 
Given the variability of materials and firing conditions if you try it please just try a small test amount first. 
Cone 1-3 Majolica White
Gerstley Borate 10.30
Nepheline Syenite 8
EPK 5.6
OM4 Ball clay 4.5
Whiting 9.75
Silic 24
Ferro Frit 3124 37.5
Zircopax 12
The alumina in your glaze is really quite high for a lowfire glaze, it's probably why you aren't getting a good melt. (alumina stiffens a glaze)
 
 
 

One of the concerns with underglaze is how it reacts to temperature. While I have no favorite brand colors at lowfire temps often can be much more vibrant. Additionally color shifts with various over glazes can be an issue. Just mentioning because paint your pottery generally favor lowfire stuff for energy use and …… bright colors. The only way to know for sure is with testing. A brief search of the web seems to Indicate low firing temperatures for colorobia.
 
 

I suggested to Ron in a PM that we drop the testing idea for the time being. Pacer ceased operations as of Nov 1, so Custer has just joined the ranks of unobtainium. Their announcement suggested they may resume at some time in the future, but nobody knows why they suddenly ceased operations or when they might resume. I suppose an independent lab analysis now might be helpful for those who have some stock on hand, but Pacer's new management a few years ago was open about publishing a revised analysis of the current product, so all a new independent analysis would tell us is whether the new management was being honest. I'd like to give them the benefit of the doubt for now. As for the future utility of doing the lab test on current stock, the near-term future is none and the long-term future is uncertain. If Pacer comes back online, we can test whatever is their "new" stock. JMO

Noticing there are tinges of green, glaze thinner? Near base edge of glaze and glaze flaw in handle. SG and glaze application of glaze same as in the testing in the alternative kiln? 
Re refiring the clay body, have you done this with the clay you are using previously?
If you post what claybody you are using, someone may have experience with this.

One more issue that could come up is how the already fired pots take to a second firing. Both the clay and the glaze getting that much more heatwork could very well have an effect on both.

Looks like the base glaze was applied with a hake brush.

One more issue that could come up is how the already fired pots take to a second firing. Both the clay and the glaze getting that much more heatwork could very well have an effect on both.

That is the exactly what lab testing does. If you follow the link I posted above for BSC you can see how they request a glaze fired sample pot, this is what they test, the fired glaze. They test for whichever oxides you pay for. Example would be if you add some stain that contains vanadium you request they test the leachate for vanadium release. It is the vanadium oxide they give you results for. Since in North America only lead and cadmium need to be below certain government approved levels on dish ware the other oxides are usually compared to drinking water levels. 

Many potters, most likely the overwhelming majority of us, either use a liner without any colouring oxides to be of concern or use one with very low levels of a colouring oxide. I have had a few glazes lab tested at BSC. 
 

As Kelly said, options for having absolutely nothing to worry about in a well balanced stable glaze would be either zero colourants or just zircopax or iron.
If you want to use a stain or a colouring oxide and want to ensure it’s safe then lab testing isn’t going to break the bank. It’s about $35 per oxide to get tested and piece of mind.
BSC testing link https://bsclab.com/pottery-testing
Home testing, using an acid such as household vinegar or lemon/lime and dishwasher testing  don’t rule a glaze “in” as being suitable for food surfaces but it will rule glazes out.

That is the exactly what lab testing does. If you follow the link I posted above for BSC you can see how they request a glaze fired sample pot, this is what they test, the fired glaze. They test for whichever oxides you pay for. Example would be if you add some stain that contains vanadium you request they test the leachate for vanadium release. It is the vanadium oxide they give you results for. Since in North America only lead and cadmium need to be below certain government approved levels on dish ware the other oxides are usually compared to drinking water levels. 

Many potters, most likely the overwhelming majority of us, either use a liner without any colouring oxides to be of concern or use one with very low levels of a colouring oxide. I have had a few glazes lab tested at BSC. 
 

One more issue that could come up is how the already fired pots take to a second firing. Both the clay and the glaze getting that much more heatwork could very well have an effect on both.

Liner glaze in the pitchers?

Lots of possibilities here, but it all comes down to you can't expect a glaze to do the same thing in a totally different kiln. First, wood kilns don't just fire in oxidation. They cycle between oxidation and reduction every time the kiln is stoked. Second, you've got a different atmosphere in the wood kiln due to ash and vapor from the wood. Third, the temperature was different, but maybe not depending on where it was placed in the kiln. Fourth, the cooling cycle was different. Different clay body? At this point I would hold off on refiring your pitchers and instead run a couple of test firings with other pieces at a higher temp and with a slower cooling cycle and see if you get the desired results. Once you've figured out what's needed, then refire the pitchers and hope they do okay with refiring. In meantime I would also start making a new batch of pitchers and offer your client a different color that you know will come out as intended. FYI, many of us, including me, have been in a similar situation at some point.

That is the exactly what lab testing does. If you follow the link I posted above for BSC you can see how they request a glaze fired sample pot, this is what they test, the fired glaze. They test for whichever oxides you pay for. Example would be if you add some stain that contains vanadium you request they test the leachate for vanadium release. It is the vanadium oxide they give you results for. Since in North America only lead and cadmium need to be below certain government approved levels on dish ware the other oxides are usually compared to drinking water levels. 

Many potters, most likely the overwhelming majority of us, either use a liner without any colouring oxides to be of concern or use one with very low levels of a colouring oxide. I have had a few glazes lab tested at BSC. 
 

Just a country boy here…
What do colorants do in a good hard (stable) glass? Stable meaning it is durable, resistant to both acid and alkali, and smooth enough microscopically to not grind away forks and spoons (cutlery markings).
“Welcome to ceramics… again.” A phrase I repeat to myself as I learn new things I thought I knew well.
If you have a strong well functioning clear liner glaze that is durable through acid (lemon juice/vinegar) and alkali (many dishwasher cycles), stays shiny, and fits your clay, then you've arrived. Zircopax will make the glaze tougher, not unlike alumina, and whiter/more opaque. No additional toxicity. Iron will alter the color and, depending on the %,  temperature, and atmosphere will, produce a great variety of effects. No additional toxicity there either. Chrome, copper, cobalt, manganese, and others rely on the hard durable glass to keep them locked in the matrix. Personally I keep those below 2%. Your worries about Mason stains are in the same vein, except encapsulated Mason stains are designed to be non leaching  in nearly all circumstances. 
If you aren’t confident in how good, hard, or stable your base glaze is, no rules of thumb will help. It is not beyond your ability to find or compose a stable glaze and that should top your to-do list.
Another line of thinking is to put all color underneath a stable glass, as in slips or underglazes. The foolproof option.
No matter what, none of the materials we ordinarily play with holds a candle to lead in terms of toxicity.
Our biggest toxic risk is mixing the glazes carelessly. 

@PyewacketteAll of the oxides in Mason stains are regarded as safe if used in a stable glaze, no different than if said oxides were used as colorants in the typical amounts in a "normal" glaze. The reds and oranges contain cadmium and selenium which would be toxic by themselves, but Mason encapsulates them in zirconium so that they do not leach out of the stain particle. The advantage of using stains to color your glazes is the variety of colors that can be easily achieved without knowing oxide combinations and amounts to add to your base glaze. The disadvantage is cost. As with so many things, you can figure it out yourself the hard way, or you can buy your way out with the gentle application of some folding green.

I rhink you inadvertently did a reduction firing. Easy to do in a small gas kiln.
Do you have time to refire one as a test making sure you have a  fully oxidised atmosphere? With that amount of copper I could get black pots without trying in my gas kiln if not careful re atmosphere.

+1
After a little googling, this looks similar:
https://www.thepostsupply.com/products/vase-no-8
I got largest image I could access from that page by opening this image into another window -- then clicking on it to enlarge it further.
https://www.thepostsupply.com/cdn/shop/files/AnemoneVaseno.8_Red_1024x1024@2x.jpg
 
Similar treatment for this one.
https://www.thepostsupply.com/cdn/shop/files/AnemoneVaseno.8_main_1024x1024@2x.jpg

 

Mason puts out a Reference Chart that lists all the ingredients in each of their stains. 
https://www.masoncolor.com/reference-guide