Min

Nope, trivalent chrome does not convert to hexavalent chrome in glazes.Re zinc chromate, according to Hansen "Chrome in zinc glazes tends to form the stable crystalline compound, zinc chromate (ZnCr2O4). which is brown." from this link. 
I plunked your glaze recipe into the glaze calc program I use but I'm not confident in the accuracy of it since specific types of potash feldspar, talc and china clay aren't mentioned in your recipe. Using generic analysis the formula is on the low side for silica though. I would do a lemon slice test on it and see if the colour changes., also keep a test piece in the dishwasher, if you use one, for a few months then compare that to an unwashed piece.What is really important is to have a stable base to prevent leaching. With colouring oxides, aka transition metals, less is better.
 

I've been using slip made with magic water and my dry claybody for years. I use a smooth white claybody and fire to cone 6. I think it makes a difference which claybody is being used, some are far more prone to handles etc popping off than others.
Magic water helps as the slip made with it is stickier than made with just water, it dries harder than plain slip and during the firing the extra sodium in the slip helps flux the slip a little more than plain slip making a stronger join post firing.

Nope, trivalent chrome does not convert to hexavalent chrome in glazes.Re zinc chromate, according to Hansen "Chrome in zinc glazes tends to form the stable crystalline compound, zinc chromate (ZnCr2O4). which is brown." from this link. 
I plunked your glaze recipe into the glaze calc program I use but I'm not confident in the accuracy of it since specific types of potash feldspar, talc and china clay aren't mentioned in your recipe. Using generic analysis the formula is on the low side for silica though. I would do a lemon slice test on it and see if the colour changes., also keep a test piece in the dishwasher, if you use one, for a few months then compare that to an unwashed piece.What is really important is to have a stable base to prevent leaching. With colouring oxides, aka transition metals, less is better.
 

I've been using slip made with magic water and my dry claybody for years. I use a smooth white claybody and fire to cone 6. I think it makes a difference which claybody is being used, some are far more prone to handles etc popping off than others.
Magic water helps as the slip made with it is stickier than made with just water, it dries harder than plain slip and during the firing the extra sodium in the slip helps flux the slip a little more than plain slip making a stronger join post firing.

Let's not throw the baby out with the bathwater here. The form of chrome used makes all the difference in the world in regards to toxicity.
Potters use chrome oxide, it is insoluble in water and gets bound in the glaze matrix in a balance glaze. It is volatile in the kiln so it can cause a pink blush on tin white glazes. Wear gloves if you get contact dermatitis with it. (it's a good idea to wear gloves whenever handling raw materials and glaze slurries to avoid skin reactions)
We do not use the exceedingly dangerous hexavalent chromium in ceramics. Iron chromate is toxic, stay away from using it.
Zinc oxide fumes from kiln firing shouldn't be breathed in, zinc can become volatile above around 850C/1560F and like all the materials we use in glazes practice good studio hygiene and wear a respirator while handling dry materials. In a glaze it isn't a problem. 
Chrome + tin pinks and reds are perfectly safe, whether in a stain or from the oxides.
 
 
 

Oh, that is a lovely green! It looks enough matte, though, to use a liner glaze with it on food surfaces. A white with tin in it could blush nicely at the lip of a vessel. (Use a liner because a matte glaze doesn’t clean as well as a gloss and can harbor bacteria over time, not to save the user from leaching-chrome exposure.)
I think you’re right that the cobalt, besides modifying the chrome, also helps to keep it from ‘browning’ or to rescue a brown by sending it toward blue - like the  little-bit-of-cobalt “cheat” in copper reds that rescues an uneven reduction red from ‘snot green or bleached white to soft blue (I learned this from a Tom Coleman student).

Let's not throw the baby out with the bathwater here. The form of chrome used makes all the difference in the world in regards to toxicity.
Potters use chrome oxide, it is insoluble in water and gets bound in the glaze matrix in a balance glaze. It is volatile in the kiln so it can cause a pink blush on tin white glazes. Wear gloves if you get contact dermatitis with it. (it's a good idea to wear gloves whenever handling raw materials and glaze slurries to avoid skin reactions)
We do not use the exceedingly dangerous hexavalent chromium in ceramics. Iron chromate is toxic, stay away from using it.
Zinc oxide fumes from kiln firing shouldn't be breathed in, zinc can become volatile above around 850C/1560F and like all the materials we use in glazes practice good studio hygiene and wear a respirator while handling dry materials. In a glaze it isn't a problem. 
Chrome + tin pinks and reds are perfectly safe, whether in a stain or from the oxides.
 
 
 

I've been using slip made with magic water and my dry claybody for years. I use a smooth white claybody and fire to cone 6. I think it makes a difference which claybody is being used, some are far more prone to handles etc popping off than others.
Magic water helps as the slip made with it is stickier than made with just water, it dries harder than plain slip and during the firing the extra sodium in the slip helps flux the slip a little more than plain slip making a stronger join post firing.

Let's not throw the baby out with the bathwater here. The form of chrome used makes all the difference in the world in regards to toxicity.
Potters use chrome oxide, it is insoluble in water and gets bound in the glaze matrix in a balance glaze. It is volatile in the kiln so it can cause a pink blush on tin white glazes. Wear gloves if you get contact dermatitis with it. (it's a good idea to wear gloves whenever handling raw materials and glaze slurries to avoid skin reactions)
We do not use the exceedingly dangerous hexavalent chromium in ceramics. Iron chromate is toxic, stay away from using it.
Zinc oxide fumes from kiln firing shouldn't be breathed in, zinc can become volatile above around 850C/1560F and like all the materials we use in glazes practice good studio hygiene and wear a respirator while handling dry materials. In a glaze it isn't a problem. 
Chrome + tin pinks and reds are perfectly safe, whether in a stain or from the oxides.
 
 
 

I think it would be safer to use a claybody with a higher thermal shock resistance like a flameware body or even a raku clay fired higher than bisque for durability.

Let's not throw the baby out with the bathwater here. The form of chrome used makes all the difference in the world in regards to toxicity.
Potters use chrome oxide, it is insoluble in water and gets bound in the glaze matrix in a balance glaze. It is volatile in the kiln so it can cause a pink blush on tin white glazes. Wear gloves if you get contact dermatitis with it. (it's a good idea to wear gloves whenever handling raw materials and glaze slurries to avoid skin reactions)
We do not use the exceedingly dangerous hexavalent chromium in ceramics. Iron chromate is toxic, stay away from using it.
Zinc oxide fumes from kiln firing shouldn't be breathed in, zinc can become volatile above around 850C/1560F and like all the materials we use in glazes practice good studio hygiene and wear a respirator while handling dry materials. In a glaze it isn't a problem. 
Chrome + tin pinks and reds are perfectly safe, whether in a stain or from the oxides.
 
 
 

I've been using slip made with magic water and my dry claybody for years. I use a smooth white claybody and fire to cone 6. I think it makes a difference which claybody is being used, some are far more prone to handles etc popping off than others.
Magic water helps as the slip made with it is stickier than made with just water, it dries harder than plain slip and during the firing the extra sodium in the slip helps flux the slip a little more than plain slip making a stronger join post firing.

Cobalt being v expensive I wonder if your glaze could handle less. 2% seems a high amount of cobalt oxide.
 

Let's not throw the baby out with the bathwater here. The form of chrome used makes all the difference in the world in regards to toxicity.
Potters use chrome oxide, it is insoluble in water and gets bound in the glaze matrix in a balance glaze. It is volatile in the kiln so it can cause a pink blush on tin white glazes. Wear gloves if you get contact dermatitis with it. (it's a good idea to wear gloves whenever handling raw materials and glaze slurries to avoid skin reactions)
We do not use the exceedingly dangerous hexavalent chromium in ceramics. Iron chromate is toxic, stay away from using it.
Zinc oxide fumes from kiln firing shouldn't be breathed in, zinc can become volatile above around 850C/1560F and like all the materials we use in glazes practice good studio hygiene and wear a respirator while handling dry materials. In a glaze it isn't a problem. 
Chrome + tin pinks and reds are perfectly safe, whether in a stain or from the oxides.
 
 
 

I prefer throwing soft clay and more often than not my clay is too firm so my go to storage is to first  pile boxes of clay in the corner of a hallway. I open the bags up and add a bit of water, do them back up and let them sit in a large rubbermaid bin filled with water for at least a few days,  I add more of bags of clay into the water filled bin as I use them up.

I prefer to use the term "durable" rather than food safe when talking about glazes. There isn't one agreed upon definition of what makes a glaze "food safe". In North America if a glaze does not contain lead or cadmium it can be labelled food safe. This is a very wide definition and adding something along the lines of what Mayco says "Finishedware producers bear responsibility for food safe testing their ware being sold into commerce." IMHO isn't good enough. Like Callie said Strontium Crystal Magic (SCM) is  fine on the outside of pots where your mouth or food won't be in contact with it.
Re lithium and toxicity, just adding a little bit. Topic of lithium and toxicity has come up in many discussions in many forums etc over the years. My impression of the reading I've done is it might not be an issue for most people but for those on lithium therapy it can be, both in the process of mixing glazes and leaching glazes.  Poison is in the dosage scenario.
With all due respect to Callie I found SCM quite rough, dry and unmelted. You could try it by itself on a test tile and see how you find it but it's a bit of a moot point because it isn't used by itself.  The overload of titanium is what makes the crystals/variegation when layered with other glazes. A good way to get interesting glaze reactions is to layer 2 or more dissimilar glazes, what one glaze lacks or has a surplus of reacts with the other glaze, this often results in interesting visual texture. SCM is loaded with fluxes to react with other glazes, that's part of the reason why it works.
Re silica and glaze durability, having as much silica and alumina in a glaze is one of the ways to ensure a durable glaze.  For cone 6 having at least 2.5 molar of silica is a good starting place, if the glaze can dissolve more then it's a good idea to add it if you are looking for a durable glaze. If you look at the screenshot above in the bottom half of the image you can see the silica is 1.68 so at the bare minimum it is about 1/3 short of where it should be. Overloading a matte glaze can quite often turn it into a gloss glaze  and really oversupplying it can turn it back into a matte and crazed glaze so there are parameters within which to work. 
Another aspect of silica that is often overlooked is the mesh size of the silica being used. When you mix glazes using a 325 mesh size silica more of the silica will likely be dissolved in the glaze than if you use 200 mesh. (not applicable for the SCM)
One more thing is to look at the colouring oxides used. Don't use crazy amounts of colouring/transition oxides, use the least you can to still achieve the effect/colour you are after.
There is a good article on toxicity that includes materials here if it helps.

I prefer to use the term "durable" rather than food safe when talking about glazes. There isn't one agreed upon definition of what makes a glaze "food safe". In North America if a glaze does not contain lead or cadmium it can be labelled food safe. This is a very wide definition and adding something along the lines of what Mayco says "Finishedware producers bear responsibility for food safe testing their ware being sold into commerce." IMHO isn't good enough. Like Callie said Strontium Crystal Magic (SCM) is  fine on the outside of pots where your mouth or food won't be in contact with it.
Re lithium and toxicity, just adding a little bit. Topic of lithium and toxicity has come up in many discussions in many forums etc over the years. My impression of the reading I've done is it might not be an issue for most people but for those on lithium therapy it can be, both in the process of mixing glazes and leaching glazes.  Poison is in the dosage scenario.
With all due respect to Callie I found SCM quite rough, dry and unmelted. You could try it by itself on a test tile and see how you find it but it's a bit of a moot point because it isn't used by itself.  The overload of titanium is what makes the crystals/variegation when layered with other glazes. A good way to get interesting glaze reactions is to layer 2 or more dissimilar glazes, what one glaze lacks or has a surplus of reacts with the other glaze, this often results in interesting visual texture. SCM is loaded with fluxes to react with other glazes, that's part of the reason why it works.
Re silica and glaze durability, having as much silica and alumina in a glaze is one of the ways to ensure a durable glaze.  For cone 6 having at least 2.5 molar of silica is a good starting place, if the glaze can dissolve more then it's a good idea to add it if you are looking for a durable glaze. If you look at the screenshot above in the bottom half of the image you can see the silica is 1.68 so at the bare minimum it is about 1/3 short of where it should be. Overloading a matte glaze can quite often turn it into a gloss glaze  and really oversupplying it can turn it back into a matte and crazed glaze so there are parameters within which to work. 
Another aspect of silica that is often overlooked is the mesh size of the silica being used. When you mix glazes using a 325 mesh size silica more of the silica will likely be dissolved in the glaze than if you use 200 mesh. (not applicable for the SCM)
One more thing is to look at the colouring oxides used. Don't use crazy amounts of colouring/transition oxides, use the least you can to still achieve the effect/colour you are after.
There is a good article on toxicity that includes materials here if it helps.

First off have a look at the materials and their amounts in the recipe itself. I re-totalled the recipe from the original 60.60 to 100 as that is the standard base amount. When we apply a standard amount it makes it easier to notice possible areas of concern. Top part of the screenshot below is the Glazy recipe re-totalled to 100.
First thing that jumps out is there is no silica added to the recipe. Yes, there will be silica in the formula from the feldspar etc but probably not enough. (more on this later) Second thing that jumps out is the amount of titanium in the recipe, nearly 12%, this is a huge amount! Third thing, is approx 40% feldspar for a ^6 glaze is getting quite high. Put these things together and you have a recipe that won't be durable (low silica), probably won't melt properly at cone 6 and is overloaded with titanium.
I know this glaze and the "warm" version of it are very popular at cone 6. It's important to note also that it isn't used as a standalone glaze, it is used as a layering glaze with one or more other glazes. What the combined chemistry is of the layered glaze is what needs to be looked at, will those be durable, I don't know, each combination would need to be looked at.
BTW, giving credit where credit is due, this glaze started off as a Tom and Elaine Coleman ^10 glaze called Yellow Crystal Matte. Barium was removed from original glaze and strontium subbed for it, the gerstley borate was subbed with the Ferro 3124 and the zinc removed.
 

 

I prefer to use the term "durable" rather than food safe when talking about glazes. There isn't one agreed upon definition of what makes a glaze "food safe". In North America if a glaze does not contain lead or cadmium it can be labelled food safe. This is a very wide definition and adding something along the lines of what Mayco says "Finishedware producers bear responsibility for food safe testing their ware being sold into commerce." IMHO isn't good enough. Like Callie said Strontium Crystal Magic (SCM) is  fine on the outside of pots where your mouth or food won't be in contact with it.
Re lithium and toxicity, just adding a little bit. Topic of lithium and toxicity has come up in many discussions in many forums etc over the years. My impression of the reading I've done is it might not be an issue for most people but for those on lithium therapy it can be, both in the process of mixing glazes and leaching glazes.  Poison is in the dosage scenario.
With all due respect to Callie I found SCM quite rough, dry and unmelted. You could try it by itself on a test tile and see how you find it but it's a bit of a moot point because it isn't used by itself.  The overload of titanium is what makes the crystals/variegation when layered with other glazes. A good way to get interesting glaze reactions is to layer 2 or more dissimilar glazes, what one glaze lacks or has a surplus of reacts with the other glaze, this often results in interesting visual texture. SCM is loaded with fluxes to react with other glazes, that's part of the reason why it works.
Re silica and glaze durability, having as much silica and alumina in a glaze is one of the ways to ensure a durable glaze.  For cone 6 having at least 2.5 molar of silica is a good starting place, if the glaze can dissolve more then it's a good idea to add it if you are looking for a durable glaze. If you look at the screenshot above in the bottom half of the image you can see the silica is 1.68 so at the bare minimum it is about 1/3 short of where it should be. Overloading a matte glaze can quite often turn it into a gloss glaze  and really oversupplying it can turn it back into a matte and crazed glaze so there are parameters within which to work. 
Another aspect of silica that is often overlooked is the mesh size of the silica being used. When you mix glazes using a 325 mesh size silica more of the silica will likely be dissolved in the glaze than if you use 200 mesh. (not applicable for the SCM)
One more thing is to look at the colouring oxides used. Don't use crazy amounts of colouring/transition oxides, use the least you can to still achieve the effect/colour you are after.
There is a good article on toxicity that includes materials here if it helps.

Copying a design versus using the same technique while making a pot are two different things. Are there any new designs in functional ware that haven't been done before by someone somewhere, I don't know but I sort of doubt it.
I have noticed quite a few makers doing exactly what you describe; leaving the mark of the making process visible at the joins. I don't think you need to waste your energy trying to justify your work. Getting inspiration from others work is one way to challenge yourself into making new forms, and making them your own.  I'm sorry you are going through this, it must have been upsetting to you.

No worries on firing when it's 40F outside.
If the glaze crazes when you remove pots from the kiln it won't be because of the temperature being a little cold. It will be because the glaze is too small for the clay. Simple way to think of this is to think of a pair of jeans and how they fit. If I wear a size 10 and my daughter wears a size 4 if I put her jeans on the seams will split. If she puts my jeans on they will bag out and fall off. Tight splitting jeans is like a crazing glaze, loose falling off jeans is like shivering glaze. Crazing is far far more common than shivering. 

I think that since so many of us fire to midrange the go to mindset is bisque low, fire higher to glaze. Problem with this when working with earthenware is more often than not the commercial glazes are rated in the 06-04 range yet many earthenware bodies will actually mature higher than this and still be porous enough to take glaze well. I haven't used the body in question, but if it can go to 02 (as the lit suggests) then I would at least try 03 and see how it does. 

It sounds like they are a special case of  "oxide washes".  (Which may be a productive search term.)
https://www.vincepitelka.com/wp-content/uploads/2016/03/Surface-Design-Patinas-and-Glazes.pdf
Dry-Effect Oxide Patinas
An interesting category of patinas are those which simply approximate the accumulation of dirt and debris found in much ancient claywork. Varying proportions of zircon opacifier or tin oxide and coloring oxides with some 3134 frit (to flux the patina onto the surface) will give a range of “dirt” colors from very light to dark brown or black.
https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/In-the-Studio-Washes-and-Patinas#
In the Studio: Washes and Patinas
Gerstley or Gillespie borate, Ferro frits 3110 or 3124, borax, or any other flux-based material can be used in combination with colorants to create patinas.
... so I think the message is to use a flux appropriate for your firing temperature.
If you say what cone/temperature you fire to an expert will probably chip in with a recommendation (or confirmation that 3134 is OK).

First off have a look at the materials and their amounts in the recipe itself. I re-totalled the recipe from the original 60.60 to 100 as that is the standard base amount. When we apply a standard amount it makes it easier to notice possible areas of concern. Top part of the screenshot below is the Glazy recipe re-totalled to 100.
First thing that jumps out is there is no silica added to the recipe. Yes, there will be silica in the formula from the feldspar etc but probably not enough. (more on this later) Second thing that jumps out is the amount of titanium in the recipe, nearly 12%, this is a huge amount! Third thing, is approx 40% feldspar for a ^6 glaze is getting quite high. Put these things together and you have a recipe that won't be durable (low silica), probably won't melt properly at cone 6 and is overloaded with titanium.
I know this glaze and the "warm" version of it are very popular at cone 6. It's important to note also that it isn't used as a standalone glaze, it is used as a layering glaze with one or more other glazes. What the combined chemistry is of the layered glaze is what needs to be looked at, will those be durable, I don't know, each combination would need to be looked at.
BTW, giving credit where credit is due, this glaze started off as a Tom and Elaine Coleman ^10 glaze called Yellow Crystal Matte. Barium was removed from original glaze and strontium subbed for it, the gerstley borate was subbed with the Ferro 3124 and the zinc removed.
 

 

Copying a design versus using the same technique while making a pot are two different things. Are there any new designs in functional ware that haven't been done before by someone somewhere, I don't know but I sort of doubt it.
I have noticed quite a few makers doing exactly what you describe; leaving the mark of the making process visible at the joins. I don't think you need to waste your energy trying to justify your work. Getting inspiration from others work is one way to challenge yourself into making new forms, and making them your own.  I'm sorry you are going through this, it must have been upsetting to you.