Min

Laguna MS29 is another nice commercial midrange clear.

I'm not familiar with your kiln, does it have a vent? Could you post a picture of the "air inlet port" and the "adjustable exhaust port"? Sounds like these might be functioning as what we on the other side of the pond use spy/peep holes for? (apart from using to see cones) People have different opinions on when an electric kiln glaze firing should be closed up during the firing. For my kiln (without a vent) I close the peep/spy holes up at around 750C. Congrats on your new kiln!

If you did get an analysis of the glaze you would probably get something like what is below which you would then need to work backwards with to make a recipe to supply those oxides. It would likely be very expensive to get testing done. Take these figures and try to make a glaze with them on Glazy without looking at a recipe and you will get an idea of how to do it.

Just as a side note the original glaze recipe you posted in no way will make a durable glaze.

How did it turn out? Picture?

Hi Juliamary and welcome to the forum! Do you have spyholes/ peepholes in the side of your kiln to see witness cones with? If not, if I was in your place, and I recently have been, I would take the time to get the controller sorted out or replaced if necessary. It's a bit like driving a car with the windscreen covered up otherwise.

@Rebekah Krieger, did you find it?

bump Anybody?

It will work if the cup was fired to maturity first and then a lower fire glaze applied and fired without the setter. Even though there is very little shrinkage from greenware to bisque fired I would hazard a guess there is enough to crack this piece where the little nub in the middle is. As the clay shrinks it will squeeze up against the nub, nub won't shrink, clay will and it will crack. Why are you only worried about the bisque of this form? Will you leave it unglazed or ? If you have access to spray glazing the finished pieces I would use your setter design as above but flip the slack over and have the clay fit the inside of the setter, including the nub then fire to maturity first then do a low fire spray glaze and re-fire.

Recipe below would probably work but it's going to take a huge amount of effort plus a kiln that can fire them to cone 10. Link is behind a paywall but you can access 3 free articles per month. https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/In-the-Studio-Make-Your-Own-Kiln-Setters#

Any chance the strange results were from the same batch of your dug clay?

Interesting. Would be interesting to look at the tiles under magnification. Could the tile glazed surfaces have the little crack fissures like those at the unglazed bottom portion of the second tile? Test tile cracks almost look like stretch marks (crazing?) on a pregnant woman's tummy.

I've done this with a copper glaze layered over one with a vanadium blue stain, didn't really blend, which ever one was the final coat over shadowed the colour below.

In regards to the "What you see is what you get" with stains I have to respectfully disagree. For example if you put a chrome tin red stain in a slip it won't turn out red (even in huge amounts) because those chome tin pink or red or purple stains need low alumina plus quite high calcium to work. Since slips are naturally high in alumina you are going to loose the colour. Matching the requirements of the stain to the slip or glaze can make a big difference in how the colours turn out. Many stains are not fussy about what the chem of the slip or glaze etc is but there are some picky ones.

So if we just look at the original recipe in this thread and your white liner the combined sodium + potassium are roughly about the same. My snowflake crackle (my current avatar) has the combined KNaO at 0.62 (in unity). Granted I fire at ^6 but if you look at all the recipes in Peter's link above or any other snowflake recipe the KNaO is much much higher than your original recipe here. My hunch is there is something else going on here. Another reason I'm thinking this is because of the 3% copper carb and the 10% zircopax. Colourants really do reduce the snowflake crazing patterning, which is a good demonstration of the power of some colourants to reduce or eliminate crazing. Just for curiosity's sake it might be fun to try the original base glaze w/without colourants, apply it really thick and see what happens.

If the new clay has been tested and is suitable for your tiles then I would be looking at adding either a small amount of a ceramic stain to the glaze or some copper carbonate. There are pro's and con's to both additions. I looked up the SDS (safety data sheet) for this glaze and it doesn't give any hints on which is used. Copper carb is prone to high amounts of gassing off which could leave pinholes or micro-bubbles in your glaze. I don't know how fluid your glaze is so this might or might not be an issue. If copper carb does induce this problem a change in firing schedule could alleviate it. A ceramic stain, probably from Mason Stains, is my other thought on what was used for the green colour in the glaze. Have a look at the Mason colour chart, find a stain you think is closest and purchase the smallest amount you can and try that. Is your glaze is in liquid form when you purchase it? If so then you need some way of measuring the dry glaze. There are a couple ways to do this but the fastest is probably to weigh out some liquid glaze then dry it out then reweigh it. When you know X volume of wet glaze equals Y weight of dry glaze try the copper carb at 1% and/or a stain at 1%. Fire those and then tinker with the amounts to fine tune the colour. (run the glaze through a 80 mesh sieve after adding the extra colourant) If you purchase your glaze dry then easy peasy just add the extra colourant to a small test amount and try that.

What does your KNaO normally run at in your other glazes?

I will sit and watch anybody who throws well but my sit and drool person was Robin Hopper.

Hi Vix and welcome to the forum! I'm going to take the liberty of editing your post's title for clarity of the subject.

Is your work for functional work with the green on the surface that comes in contact with food or drink? Is it important to be translucent?

Looks like a massive version of a snowflake glaze pattern.

This one? If so then maybe Clay Art Center in New York would share the recipe? (I'm running out of image storage so will delete the image in a short while)

Hi and welcome to the forum! Hopefully the cost of lithium products will be coming down sooner rather than later. The Sayona mine in Quebec Canada is set to reopen fairly soon. Also with the extraction method that uses ponds to evaporate seawater for it's lithia content there is also talk of using water from Turkey (I think) that has been found that has a higher concentration of lithia than is the norm so that should help too. When the Canadian spod no longer was available 20 odd years ago there was a lot of outcry that shino glazes were not working as well with the Australian spod. I think that came down to the Canadian spod had a tiny bit of iron in it. The combo of sodium plus potassium aids in the melting of the lithia, I would be looking at those also. With the petalite version recipe how much is the silica too high? (since gram for gram it is lower in lithia)

Bracker's Good Earth Clays in Kansas is offering grants to local schools. Last year grants were available nationwide in the US, this year they are focusing on local school art programs. "We service most of Kansas & Nebraska, about half of Missouri, Iowa, Oklahoma and Arkansas, and a bit of Illinois." from the link below, maybe somebody here could befit their school art program. (I am not affiliated in any way with Bracker's, I just get their emails which is where I saw this) https://us10.campaign-archive.com/?u=ff0b391198e5566d2026a0bfe&id=5ff6d9e137

I don’t know Rae, think your bad experience isn’t something you messed up on. You are too nice a person to anticipate someone being so nasty. The rest of us, yeah, we messed up!