ATauer

Thank you! I have emailed Tony Hansen, who is such a wonderful human being about answering questions related to his blog posts, about his recommendation to have thixotropic glazes because of much it improves dipping and a long list of benefits, about whether he would recommend doing it for spraying and painting the way I’ve described, since I have a spray gun that can handle super super thick glazes and even latex paint, but still works for delicate little ceramics pieces, so depending on his answer, I may be making my glazes significantly thicker and using Epsom salts with all of them. If I do that, since I’d be using less water, I will do some tests to see if I need to adjust the amount of CMC water (and try to remember to come back here and report on results) in a thixotropic glaze or not. Depends I imagine on just how much less water I would use.

See my other post, people are abandoning lowfire bodies in droves because they are completely unusable, that is a lot different than just consistency issues we’ve always had to deal with. From what I hear, lowfire talc bodies are no longer extremely popular and they are also not fitting glazes so easy anymore. It is also not hypothetical- I’ve seen the data, I just can’t share it because it is in a class where everything is proprietary and I can’t share slides otherwise I would show you the data, that is robust and done using the scientific method appropriately. There have been plenty of lowfire bodies without any talc over the centuries that fit glazes fine, lots of terra cottas being used currently and for decades without any talc that also fit glazes fine, lots of wild clay bodies that are terra cottas that do well with glazes, it is very possible there are other reasons and other ingredients. Including the increasing improvement in commercial glazes, how they make them and what they put in them, that especially at low fire make them fit much better than they used to a wide amount of different claybodies, in fact some that fit pretty much every lowfire clay and often if you try even cone 6 and cone 10. Consistency has been an issue usually over the course of years for most materials, most mines take quite some time of producing the same material before that is used up and they go deeper and the chemistry changes a little which usually just requires some mild adjustment for the majority of things. There are some exceptions, like rutile, where they always say if you find some you like buy 50 or 100 lb to last you the rest of your career because it changes much more often in the mines and there are many different mines that are used and suppliers change them frequently for some reason without telling you. And over a number of years feldspar mines have been mined out or closed, so *sometimes* changes have to be made for feldspars, a lot kinda close together ran out but before that the feldspar changes had been usually with quite a few years in between- for me they don’t (not until the Canadian neph sye runs out) because I have a thing about not having a lot of feldspars taking up space, I alter almost every single glaze so I can use neph sye using glaze calc (amazing the number of glazes that has improved significantly) except the extremely rare times that it has has affected color or COE, but usually when I alter the glazes to use neph sye the calculated COE goes down to my surprise, if it needs Cornwall stone I have found I can’t glaze calc my way out of that but I have switched from using the stuff I can get at my supplier which I don’t know how reliable it is and do the home made recipe for consistency-plus it is all stuff I have on hand anyway. I try and limit a lot of my ingredients- I refuse to use wollastonite as it is a PIA and I much prefer whiting & just adding more silica. I try and alter things so I can use dolomite instead of talc, especially now. It is possible to not have much in the way of consistency problems if you know the materials that are problems- talc, Cornwall stone, feldspars, rutile, some metal oxides, etc, and find ways around them or buy big bags of certain problematic things and when you get to the point you need to resupply test test test. Over all consistency is not as much of an issue the same way talc has been an issue over the last few years, where month to month there are problems and changes. It doesn’t have to be like this in North America either, there are tons of talc mines in other countries, just no company is willing to ship over here. Yes it would cost more and that’s a bummer, but there are huge talc mines in lots of countries with pretty consistent chemistries and enough to last decades. I don’t understand why no companies will import them. Other countries do not have talc issues, they often have plenty of other sourcing and consistency issues but not talc. I’m trying to think of what I’m going to miss when I move to France, where talc is not an issue and I can get most of what I already use or they have consistent supplies of almost the same chemistries as what I have been using so my glazes shouldn’t change too much. I can even get mason stains, which I prefer, although I’d probably adjust to what stains are cheaper. From my conversations with French ceramic artists and my friends in nearby European countries who are fellow glaze nerds I should have a lot less problems getting things and have good consistency, and access to a ton of things I don’t have access to in the US, some things in particular that should improve my work considerably and a number of things that will allow me to do things I can’t do now. And while I don’t use it much, just in certain glazes, no talc issues!

Hansen doesn’t really have any evidence, that is what I pointed out, he has one data point. I have seen lots of data that I’m not sure if it is proprietary but it had a lot more actual evidence and appropriate scientific method where the control was the same thermal expansion as the clays without talc. I already posted what would need to be done with Tony Hansen’s anecdotal evidence to determine using a dilatometer if the talc actually increases the thermal expansion. His own explanation of what happens in lowfire bodies in fact argues against talc increasing thermal expansion. Talc bodies may have always been short and hard to work with what I’m saying is that people are complaining in large numbers throughout the country to the for Flux Sake Podcast and other people that the talc currently being used is much, much worse, to the point they can’t work with the bodies anymore at all. And there has been a clear, rapid change in school and park and small art centers that give lessons to converting to cone 6 instead of lowfire anymore (one of my former teachers did it just as I left her classes, still makes me mad she didn’t do it earlier) because the clays are so awful they can’t teach with them. I’m also seeing in a ton of Facebook forums hobbiests and even professionals asking for advice about cone 6 bodies and glazes as they have just converted because they couldn’t find a lowfire body they could work with anymore, many having been doing lowfire work for years and being very committed to traditional majolica or specific glaze colors that are harder to get at higher temps and doing it because they feel they have no choice. That is a lot different that just the status quo.

They are not dipping glazes, they are sprayed or painted, and it isn’t brushing as I pointed out (which typically just involves quickly brushing the glaze with a hake in three coats letting it dry between and that is it), it is painting, which involves diluting or the opposite, making thicker with gum arabic usually and adding CMC and often polypropylene to help with the painting,-which involves applying with a variety of different kinds of brushes in varying thicknesses and amounts, usually not counting coats but going for certain affects, shading, doing it just like you would paint a watercolor or oil painting on a canvas. So I’m asking how much CMC liquid the way you suggested making it up with the copper already in it as part of the water used for making the glaze. Right now, as I believe I said, I only add CMC to a separated portion of the main glaze for when I’m going to be painting. There are occasional times I also add it to a portion of a glaze that is going to be sprayed, if I feel for some reason it needssome extra help sticking to the bisque. Since they are NOT being dipped, ever, would you recommend altering your instructions, and could you give an approximate amount of CMC water to use when mixing the glazes.

I’ve only ever seen copper carb used for antimicrobial properties. I am not sure if there is any true difference in how it works, or whether there are different concerns for toxicity, I looked at an MSDS sheet for black copper oxide and compared it to copper carbonate’s, and there seems to be a bit more concern with copper oxide with inhalation and ingestion toxicity and its severity than with copper carb, ingestion we are going to rule out here as a concern so it is the MSDS sheet’s warning that inhalation could exacerbate other ongoing lung disease or from chronic exposure to cu oxide develop respiratory disease. It says the OSHA daily occupational limit is 1 mg/m^3 TWA, which with the small amounts we deal with and put in our glazes and especially in this CMC recipe I think it would be hard to get that high of a level of copper oxide in the air, even with dust and fumes, which is says to avoid of course. OSHA doesn’t even recommend wearing ventilators or dust masks unless the air levels are significantly higher than their limit, for up to their limit they just recommend good ventilation. So to try to come to a conclusion, I would suspect cu oxide would work just fine but can’t say 100% without testing because I just have seen it used for antimicrobial growth suppression. Copper carbonate is copper oxide with some added water, so honestly it is surprising to me they even have different MSDS sheets, but apparently they do have some slightly different issues with toxicity. I think there is no harm in trying and if your CMC enriched test glaze doesn’t go bad, then I would say go ahead and use it. It is too small of an amount to flux or color the glaze so there is little harm in it as long as you don’t eat it!

You said the right amount of soda and kaolin mixed starts to turn to a Nepheline around cone 0, while Nepheline Syenite when it starts to melt around cone 2 or 4 I think it is will end up on its own melting into a glossy glaze, it just crazes terribly because the amount of sodium in neph sye. I’m wondering if the Nepheline that forms around cone 0 with soda and kaolin would also form a glaze at around that temp or up to cone 06…which is how high I usually fire my raku kiln when I add soda ash to it. They always say at that temperature you can’t form any glazes, it isn’t hot enough, but they aren’t talking about the Nepheline, right? I’m probably groping in the dark here, I’m just wondering how I could use the fact that Nepheline is forming, which if it is close enough in chemistry to neph sye might form a glaze, even if it crazes, that wouldn’t be a problem with raku work. I’m just trying to figure out if I can use this new knowledge to produce something at cone 06….

Yeah, the markings appear on both the terra sig and the clay body, it seems to just affect any clay it seems, doesn’t matter if it is in slip form or from a body. It seems to stand out more over the terra sig though, it is not as noticeable on the bare clay, probably because of the color and sheen of the terra sig versus the matte clay- plus I have only used it on porcelains & porcelaneous stoneware so far personally so they are very white clays and the white from the soda ash isn’t very noticeable then. I am planning on using it on some speckled light brown stoneware and black stoneware I have soon though and I think it will stand out more on them. I feel like calling it scum makes it sound a lot worse looking than it is, I could also say it looks a lot like when your car gets scratched and has white marks, or a metal tin gets scratched, or even scratched antique wood- maybe that is a better analogy, because sometimes scratched antique wood looks very nice. If I’m using the soda ash wash instead of borax or lithium (both tend to have much more of a sheen, but can also leave some marks, the lithium especially I think if too much is put on kind of bubbles up, but they are much more consistent in leaving a sheen- I mean some people still use saturated borax washes or borax with minimal other ingredients to form a low fired glaze!) it is because I want the white marks which have a distinct look that makes the object look antique and old, my favorite is to use it over Grolleg terra sig colored with either the Bermuda or Celadon mason stains, which look a lot like an opaque burnished celadon/light turquoise, and put the soda ash wash over that and it looks absolutely gorgeous with those colors and the markings. I usually try to avoid getting it on the bare clay but again with my clays it doesn’t show up much anyway. I’m thinking of trying it on my black stoneware on the raw clay, no slip or terra sig or glaze, I think it will look very interesting, since from what I’ve seen of it it works about the same on every clay, so I’m pretty sure it should develop the same on black stoneware. You can also adjust, with some degree of control although not totally, there are plenty of times I’ve put it on and it did want it is really supposed to do, leave a sheen with no white marking, based on how much soda ash you have saturated in your water how much of the scum stuff shows up, it can vary from very little to almost completely covering up all the terra sig. I try and usually aim for the middle ground, so I don’t use a completely saturated solution. Unfortunately I don’t have access to my notes right now about how much I use, it is something like a teaspoon or tablespoon of soda ash per cup of water, probably a teaspoon as a tablespoon for a cup of water sounds like a lot to me right now! I’ll be very interested to hear your results. I’m hoping to begin doing some reduction firing soonish and eventually some soda firing, and I haven’t had any interest in flashing slips because I’m not a fan of the colors orange and brown/tan, which are most often the colors you get with flashing slips, although I do hear you can get reddish sometimes. But if washes alter how they look I might develop an interest in trying them. If only the flashing was a real nice red a lot more I’d be banging down the door to start using them. As it is, my plans to move to Europe in little over a year will result in me starting to definitely do soda firing, and maybe salt firing. I’m mostly interested in the wonderful clear glaze they can provide, and some of the affects of the process on glazes, colored slips, and underglazes you decorate with, without flashing or carbonization. I’m sure all the atmospheric people are shaking their heads at me, thinking about all I’m missing out on! I use soda in my raku kiln, the temperatures aren’t high enough to form a glaze although when I put an equal amount of borax in the newspaper twists I fill and dunk in water and throw in the kiln, it comes so close to making a glaze. But it induced immediate deep in kiln reduction, and has really interesting different effects on the glazes, bare clay, and slips on the ware that I love- and for one thing turns my copper luster pots blood red just perfectly, the only way I get really good looking “copper red” pots right now. I wonder if it would work on flashing slips at that low temp or not…no one has ever mentioned them when discussing lowfire or raku soda to me but I probably need to buy that new book that came out on lowfire soda firing.

I would need to go back and find that lecture and watch it again, I paid attention a lot to the rant about talc as a lowfire flux because it was a real hopped up rant which is always entertaining but since I have no interest in lowfire bodies I was not as interested in the rest of that part, mostly I remember seeing some charts and I think him saying that the other so-called benefits of using it in lowfire bodies didn’t really have the evidence to back up those claims and I thought I saw some proprietary data on it. But I will have to go back and rewatch to make sure about that part. I think the point was like we see in the Digitalfire blog photo I linked to, talc is inert at those temperatures, if it isn’t melting then it can’t be affecting the thermal expansion, because it’s oxides are not active. They are just a powder that doesn’t melt, and don’t interact with the rest of the materials. That’s what I’m remembering as the reasoning. That it of course does very much act to *lower* thermal expansion at cone 6 and cone 10 because of the effects of Mg. That it wouldn’t have any effect either way in a lowfire glaze, either, same reasoning as before, its not melting and interacting with the rest of the glaze materials. As a thought experiment, based off of the photo proving that talc does not melt *at all* at lowfire temps, something I’ve seen before too, pictures of it not melting, then the material doesn’t interact with the other materials during the firing, which it would need to do to increase expansion. I would think that it would just keep expansion the same as if it wasn’t in the clay, as it isn’t lowering or raising it. Tony mentions that all the minerals are just sintered and mostly just remain the same. Which to me would indicate that the Mg wouldn’t do anything to the thermal expansion. I know he shows a graph too, so I’ve got fighting graphs to contend with, but using dilatometers is notoriously tricky and not easy to get accurate results. I would need like a bunch of trials, not just one time that he did this on one clay, but 20 or 30 repetitions and also several versions using different clays with talc in them, (which Matt showed us talc in a variety of clays all not fluxing at all at that temp), that’s what I would do in a clinical trial basically, in order to get the best information, including a control low-fire clay with the exact same ingredients as the first one but without the talc to really evaluate it. I never trust one time dilatometer results.

This is a great way to do it, I have only heard of directly adding the cu carb to the glaze! Which is still good to know how to do in case you forgot to mix up your glaze this way. For me I’m a little unsure how much I should use when mixing glazes, I spray versus paint (not brushing, but literally doing as they say “in a painterly fashion”) about 50:50. And while there are some glazes I will know I will definitely not be painting with (floating blues for example) a lot of glazes can go either way. What would you suggest Min? They are such different things, and when I paint a lot of time I’m diluting the glazes a lot to make them more like watercolors, or doing the opposite, thickening them with gum arabic to mimic oils or acrylics. And even if I don’t have a ton of glaze issues to worry about, I like having CMC in my glazes, it comforts me knowing the CMC is really attaching that glaze to the clay, even if it might dry a little slower, so what, I’m a sculptor, I’m not on a deadline to glaze 50 mugs in a day. Another thing I’d love some advice on is I’m going to be working soon on trying to optimize single firing my very large scale sculptures that are cut into sections to fit in the kilns, doing so would save me a bunch of firings. It is hard enough to figure out how to optimize it without spending the large amount of time to make a bunch of 6 ft tall sculptures to practice the firing and glazes on, thinking about how I might use this with single firing and likely with pretty long schedules because of the size of the pieces…although I don’t know that for sure yet, I make them out of paperclay porcelain, so their walls are actually quite thin even if they are huge. So they shouldn’t need as long as a regular large scale sculptor who use thick groggy clay with 2.5 inch-3 inch walls would…Would you recommend using this at all with single firing (which probably could benefit from it as the clay is not going to be as thirsty and porous as bisque), does it matter at all if it’s put on before bisque or if the glazes are fired for longer than is typical? Probably tough questions…

I just wanted to add, I found on the Bartlett website a document on what you need and how to put together the complete controller from what you get when you buy it. Down at the bottom for V6-cf besides the manual and firing profiles they have the connections diagram, which is one of the best electrical diagrams I have seen over the last few months, and the technical manual, which includes some things that would help with putting it all together. https://www.bartinst.com/manuals/kiln In November I think I called them trying to find out about if it was a faceplate or a controller, which lead to a lot of my confusion about things, but the customer service was really nice and I think I might have talked to a tech there, an older gentlemen who has been with the company a long time, so I think if I need help I can probably get some help with putting it together from them. Cross fingers they are like Skutt’s techs.

I know just enough about PIDs to know about the loops, but your information was very helpful. I guess the misunderstanding was I was thinking with the Bartlett I would still have to do the programming and didn’t realize it came with so much. Having everything you mentioned-I don’t have three zones currently in my kiln but it is a big enough Skutt that I absolutely could go that way if I start noticing big differences between sections. The other things-especially the fail safe programming, which I worry about, although I do use the kiln sitter with a cone several cones higher than what I am firing to to make sure that if my electronic controller doesn’t turn off the kiln the kilnsitter will if the kiln starts heating up and might cause problems on another kiln, the multiple programs, alarms….since I absolutely can’t find any commercial kiln electronic controllers for anything under $800 + shipping $$$, paying ~$300 plus the ~$100 in parts I already have (not counting some parts I won’t need that I will be able to sell for a decent return) is a price I’m willing to pay to get rid of this headache and not have to stress about it any longer, and the side benefit of not having to brush up on my coding! Thank you so much for taking the time to make it really clear what I would be buying and that I should easily be able to put the rest of what it needs together with what I have, and probably have a number of things left over to sell as well. I feel super confident in deciding to go for it, and I feel like 50 lb has been taken off my shoulders-thank you! Now to wait to Monday to make the call to make sure I know exactly what I’m getting at the place I plan to buy it and hopefully purchase it!!!! One of my big needs taken care of, finally! Now let’s see if you can pull a giant electric kiln out of your hat I feel like the downside is we still haven’t identified the perfect RaspberryPi controller for the readers. I know I desperately wanted for many months of googling to just come upon something that mentioned it!

My experience with soda ash washes is not directly related to how you use them, but I thought the information might be valuable because it involves using them with terra sigillatas which are a kind of slip, and though typically thinner and made out of smaller particles, I use Grolleg terra sig quite a bit which is at least a porcelain which most flashing slips are also. I use terra sig in a variety of ways, some fairly traditional but most of the time not traditional. I often fire it at cone 6 or 8 in oxidation, and lowfire it in raku usually at cone 06 but sometimes down to 1700F, which is often in-kiln reduced as well as the post fire reduction, so definitely different than high fire reduction but still legitimate reduction and not just post-firing. I use a variety of washes and often glazes over it, or leave it plain (or colored with mason stain and unglazed). In both oxidation and the lowfire gas reduction, the soda ash wash tends to leave, I’m not sure how best to describe it, whitish almost scum markings, which can actually look very attractive and are usually the reason I use it, because it makes that part of the ware look antique and old in a good way. To ensure I get that I apply a decent amount over the top of the terra sig in bone dry or bisque. If I want a sheen I definitely don’t use soda ash- which when applied under the terra sig has less of an affect on the surface but definitely doesn’t leave a sheen. I know it theoretically can with terra sig but I’ve never seen it actually happen with anyone I know, or myself, and I would think it would have a good chance of leaving white scum/scruff marks and dotting on slip as well. If I want a sheen I use borax or lithium carb washes instead. Often under the sig, that tends to lessen the amount of sheen possible by a little (not so much it makes a huge difference) but it dramatically reduces the odds that either will leave any marking or rough up the texture like putting the washes over the sig might. Not a lot to help you with, but the fact that soda ash washes leave, just pretty much every time, that whitish scum and spots and streaks on a different kind of slip just means I would urge some caution- and I know for a fact it does it in gas reduction as well. Hopefully it would do that less at cone 10 as it ideally should flux better, but I know people who have been disappointed with seeing those results after a cone 10 gas reduction. I would suggest while you are experimenting maybe trying out borax and lithium carb washes too, they can produce just gorgeous sheens on sig at cone 6 and would fully flux at cone 10, making them likely to have a stronger sheen/be quite shiny even in gas reduction as well, although I have no idea about flashing. Hope this helped a little, and wasn’t too different to be of use.

Just for those of you who haven’t had the benefit of seeing Matt Katz lecture in his CMW Intro to Clay class were he rips apart all notions that talc acts as a flux in clay at lowfire temperatures, particularly the 06-04 range using a huge amount of data he has amassed through a bunch of experiments. There isn’t that much information on this out there that has been published though, and there are still a lot of clay suppliers who are making lowfire clay with up to 50% of it made of talc. I know there are some ideas it helps with glaze fit and crazing but he also showed us there was no data to support that in lowfire claybodies. Anyway, I came across this little experiment Tony Hansen did on Digitalfire which also includes some interesting visual data about some other materials as well! Matt’s suggestion to us was of course to fire to cone 10, because that is what he wants everyone to do always anyway, lol, but basically urged us if we were to be buying lowfire clays (including reds/terra cottas, talc is put in them a lot as well) to ask the suppliers for a data sheet on the materials in the clay to make sure there is no talc in it, and if the supplier won’t give that to you its time to change suppliers. At the very least you are entitled to the MSDS sheet on the clay and talc is a material they would have to list-just check the date and make sure it isn’t 20 years old which I’ve often found & usually they’d had recipe changes in that time. And no, I am not anti-talc, I quite love talc at higher temperatures in glazes! I’m quite worried about our future with talc, yes I know there is Cim-talc but I’ve been told it performs terribly in glazes by someone who should know, and it seems like any time a mine becomes available it is lost to us 6 months later. Our materials, as this linked blog post shows, are just so important to us, and without consistency…. https://digitalfire.com/picture/1115

CMC definitely burns off! It is methylcellulose, so glue basically made from the fibers in trees. The way I use it I usually don’t put it in a big 5 gallon bucket of glaze because it can rot, I remove a portion of glaze that I am planning on using soon and add the CMC just to that, that way it won’t rot. But it doesn’t help your 5 gallon bucket of glaze, unless when you add CMC to it you add a pinch of copper carbonate. I learned that on Glazy from a real super star of a glaze maker/inventor, and it makes tons of sense to me because I use 0.2% per dry weight of cu carb mixed with my paperclay to keep it from growing mold and the cellulose in it breaking down, and it works so well the clay will last for at least two years. I don’t think anyone has left the clay longer than that to see how long it could really go. It is used interestingly enough in antimicrobial cleaners in baby wards in hospitals for its antimicrobial/anti mold properties, while having an extremely low risk of toxicity of any kind. Been used like that for decades if not longer, so it legit will keep your CMC from rotting the glaze without having really any toxicity issues you need to worry about unless you drink your glaze, and even then I happen to know the dose would be too low to give you any symptoms! I know a pinch is rather hard to measure! You want enough to prevent rotting in the glaze without adding color or fluxing the glaze. You kind of have to play around a little to know how much that is, but around a 1/2 teaspoon to 5 gallons of glaze often works. There are other variables, like the weather, humidity, heat levels etc where you keep your glazes in how much it will want to grow bad stuff, so you may have to play around with the amount. And CMC in powder form is quite cheap, cheaper than anything else I’ve seen for the problems it treats. Just randomly, as I know you’ve said some of your glazes get cracks in them on the bisque and some of those types of issues, another thing you can do to help with that is use Karo syrup in the glaze (only the amount you are going to apply) and it is so sticky that it seals the glaze to the bisque and makes issues like that disappear. It often makes brushing on glazes much easier as well if you need to do that and your glaze is formulated for dipping. Which brings me to a thought I’ve had about your glazes, and adding binders and stuff- making sure you know the difference between a dipping glaze and a base coat dipping glaze, and make sure you are aware of which one you are making, and how that effects application and firing and flaws…this is especially important if you are dipping more than once, or layering. Two great links on the differences between the two and what you need to do and what to look out for…it may be that some of the problems you are having is you are using one when you should be using the other… https://digitalfire.com/glossary/base-coat+dipping+glaze https://digitalfire.com/glossary/dipping+glaze

You also might want to look at your bisque and glaze firing schedules again. A lot of the firing flaws could potentially be fixed by a drop and hold and slow cool schedule, I don’t think you mentioned what you do, I’m making an assumption you fire to cone 5 or 6 so if you lowfire or are cone 10 the exact cones I mention are not as important as the points I make about them. Make sure you are bisqueing at the right temp for these glazes and consistently using the same temp for the bisque, no over firing and always use the exact same cone consistently without fail (witness cones!). The only exceptions are you can bisque lower if you are doing raku or pitfiring/barrelfiring/saggarfiring. And you might want to look at the glaze temperature you are firing to, according to your cones, maybe that needs to be altered if your kiln’s programmed cone is actually different than the right temp for that cone, it may need adjusting. As Matt Katz is always reminding everyone, cone 5 is super far actually from cone 6 when you look at the degrees, compared to the distance between other cones. Glazes can perform very differently between the two, even though people say cone 5/6 like they are the same thing, and even just with over firing to cone 7 which a lot of people do a lot without knowing it. Getting all the way to cone 6 if you don’t use witness cones with every firing could be a problem, or if you are firing to cone 5 a lot of the glazes may be underfiring. And you’d be surprised sometimes how small of a range some glazes have, where cone 7 is hugely over firing…while others can fire from cone 06-10 (that’s really just the Stroke & Coats and the reverse engineered recipe for them on Glazy, but there are a surprising number of glazes that work from cone 4-10 with minimal visible changes.) Good luck, I hope you find something that helps.