Very satisfying kiln opening last night. Cold night though, I cleaned out the woodstove (it holds a 5 gallon bucket of ashes while still being super useable) and started a new fire. Everything's clean from the equinox cleaning though.
I was using some pretty runny glazes so at last minute I was catastrophizing about things running all over. I'd followed good practices, leaving deep feet and wiping back so the bottom glaze was thinner. Everything turned out well. I think I had 40 pieces in this kiln load, I'm averaging just slightly more than one per day.
A highlight of this opening was a series of carved-mug clay-and-glaze tests I'd done. The carved mugs, together with the glazes I'm settled into, feel like they're approaching a personal style that can evolve over time but still feel relatively related. Variation happens through using the same glaze on different clay bodies, or through layering the set of glazes in different ways, plus through the carving.
I also made up a glaze that turned out quite nice, and I think I'll do some colour tweaking with it.
I also am figuring out issues with some glazes and figuring which ones aren't worth making again.
There have been a couple issues with clay bodies, especially where I swirled the IMCO Night clay in with anything. Plainsman clays seem to swirl ok with other plainsman clays, but maybe best not to cross brands.
So, more info with glazes:
My storebought Georgie's hot orchid doesn't cover dark clays.
The New Hagi ash glaze bubbles when too thick, and maybe isn't as good at cone 5 1/2 as at 6. I'll need to work on the glaze a little more, as one would expect. I would like to try doing maybe a triaxial blend mixing different proportions of that wood ash, of maybe my local clay, and a melting agent to see what I can pull out. Someone online calls that kind of testing "discovering glazes" and I'll need to do it each time I have new clays or a new batch of wood ash.
The Oldforge Floating Copper remains almost nuclear glowing, though where I used copper oxide instead of copper carbonate it is much specklier and not quite as even, I think? Also there's a difference between the 1% (glowing green-blue) and 3% (glowing blue) copper carb, so it might be worth keeping a couple different buckets around of each. This is 100% a keeper.
The Oldforge Floating Iron is a beautiful blue breaking warm brown on darker clay bodies, it's oranger on light bodies. It's truly gorgeous over the dark ones, flowing and depthy, and it's a keeper but it needs a bigger bucket for full dunking.
Val's Turquoise 3134 is thick, covering, and reliable. It even covers IMCO Night. Seems like Val Cushing did several turquoises, this one is an adaptation, and it's glossy. It's definitely going to be a longterm one, though not easily on carving unless it's wiped back. Sadly their Matte Turquoise uses materials that aren't available, but I'm considering trying to adapt it.
Celadon Chun with Minspar is clear, like the hot orchid, so it really needs a big bucket for even dipping. It looks like it's going to be a good layering glaze, which would be lovely-- I'm just starting to explore that.
Oldforge Misty Sunrise I was hoping would be a good manganese something. It's a weird brown on darker bodies, though a pleasant peachy sand colour on light. I probably won't make more of this. I do want to look into manganese violets though, and the chemical makes nice mirror surfaces too.
Ravenscrag Floating Blue is a much softer blue than Alberta Slip. It's less floating but it breaks well; it's almost a baby blue version. I'm not sure how I feel about this so I'll use the cup for a bit, use the rest of the tester up in a couple different situations, and consider.
My Ravenscrag floating copper was an attempt at putting turquoise colours into a local-materials, simple glaze. I used 3% copper, I think, and it's a serene smooth green towards aqua surface. I'm very pleased, and I want to take that same base and do some colourant testing, as well as trying titanium and rutile in it for better variegation.
Storebought "Pumpernickel" from the pottery supply house looks glorious over dark clays with carving and texture. Probably will keep buying?
Storebought "AMACO seaweed" is weird on its own, but glorious with even a single layer under both the cedar hill white at the studio and my ash glaze. It's especially glorious under both. There's a lovely brown break over texture and blue/green/paleish flow down smooth facets. There's something on glazy called "Leah's Seaweed" which I want to check and see if it's a reasonable equivalent that I can make myself, it's based on oldforge glazes so I'm helpful.
As for glazes we tried at the studio, "bubblegum" from glazy, which I translated from dutch, is the only reliable pink I've seen. It covers texture, looks like, but it's a very very good pink.
The Alberta Slip floating blue doesn't seem to care whether we use 1 or 2% cobalt, though it's still super thick.
We added 1% clay and 1.25% silica to the Oldforge Misty Forest and it doesn't seem to be crazing at all. The phase separation and flow is a little reduced, but that could be the cooler fire as well. It looks great. I need to do some boiling water/ice tests on it to make sure it isn't crazing, but I'm hopeful. Given just how much it's not crazing, and where in the stull chart it lands, I'm wondering if we didn't mis-measure when we did the first test somehow. Either way, that's good. I can't wait to have a full bucket of this for easy dipping, and to compare it side-by-side to the floating copper which is the same ingredients in slightly different proportions.
The raspberry riff asked for more than half as much again water as most glazes, and on the test pot it looked very thin. So, gonna try removing some water and seeing what happens. I think the bubblegum will be what we go with though, for purple/pinks.
I need to make up a new bucket of opal blue since the one we have is almost gone.
Clay bodies, current state:
I'm getting more of a handle on these now.
Buff/Brown:
Plainsman Pioneer Dark is really hard to cover with glaze, and it's a nice buff brown. It throws well and cracks slightly on drying. It has very low absorption.
M332 is a good sandy brown, darker than pioneer dark but in the same brown family. Unfortunately they've tweaked it to be very absorptive, up to 5%. Otherwise I'd use it instead of pioneer dark since it doesn't crack and it's cheap. I'm reluctant to use it on food now because it's all on the glaze to prevent absorption, and part of the beauty of these coloured clays is leaving them bare. It takes glaze really nicely, too.
So of the above two I only need one brown, I'm not super happy with either? I'm considering trying M350 which is lighter brown and less absorbent than M332, but still not as vitrified as I'd like.
Black:
IMCO Night remains challenging to work with but I think will be easier on our cone 5 1/2 fires than cone 6 ones. I like how much it alters glazes (doesn't just eat them like the pioneer dark) and I will keep using it. It's special.
Plainsman Coffee actually has retained an ok level of vitrification/lack of absorbency with the recent changes. It's less black and more a deep brown but not as earthy as that description would suggest. It takes glazes nicely, alchemizes carvings and blues especially, and is nice to throw with. I'll keep using this one even though it's expensive.
Red:
Whoo, ok.
Dundee red and Mazama red: I still keep mixing up these two Georgie's clays. I think Mazama red is the oranger one, and Dundee is the redder one? The redder one is gorgeous, speckles and influences glazes strongly, and the box I got was hard to throw because it was so wet. I'm not sure if drying it out a little before I used it would help. The oranger one also speckles glazes strongly, almost as much as an actual speckled clay, which lends a neat effect to some glazes. It's easier to throw but not as spectacular. Neither are hugely expensive but they are a bit challenging to get, and both vitrify well. I think the Dundee might go almost purple when it flashes at the edge of the glazes. I'm putting these in the "play with in the future" category. It also cracks on drying, like the pioneer dark, particularly S cracks on mugs.
M390 is the red plainsman clay, so it's been tweaked to be more porous as the others have been. It annoys me to no end that plainsman, which is the local clay company, doesn't make a fully food safe (eg doesn't harbour bacteria in pores) clay that can take not being fully glazed and still reach the highest standard of safety. I know it's hard with red clays, iron melts at too low a temperature. I know a lot of clays that fire to these temperatures are a lot worse, and even plainsman offers worse ones. Still, I'm not happy. This will likely be my red clay of choice but I am hoping more trials with Dundee above let me make better friends with it. There aren't too many other brands available here. Anyhow, the 390 throws well, carves well, doesn't crack, and is nice to glazes. It just has a bit more porosity than I'd like.
Both Tucker's and PSH offer red and brown clays that may work better, but shipping is likely a lot. I may look into them anyhow? Feels weird to test so many and not come up with any I'm fully satisfied with.
White, buff, and porcelain:
Trillium white porcelain by Georgie's I haven' tested yet.
P300 porcelain by plainsman is lovely to throw but dried/hardens in the block pretty quickly. It's fully vitreous when fired and it shows glazes brightly, without adding any variation. I want to play with carving this, though it isn't cheap. It's weird to carve things when so much is discarded. Anyhow, this doesn't crack on me and it's easy to work with. It's weird to keep around because it hardens though.
M370 is a plainsman white clay that's a little stronger than the p300 but still fires very white and smooth. It's a little more interesting with glazes over it than the porcelain is, that is, it alters the glaze a bit but not a lot. It's ok carved. It's a hair less expensive than the p300 but not much, and it keeps longer. Right now it's my go-to clay where I'm just trying to do a glazed design without really interacting with the clay. I suspect it'll keep being my default for now.
M340 is a plainsman buff clay. It's super cheap, kind of sandy, and in the past I haven't liked it as much because I didn't love the colour of the clay when fired: kind of a medium beige. I'm going to trial it for pieces that are completely covered in glaze so the colour of the clay doesn't matter, and I think it might show through green glaze when it has strongly carved texture in an interesting way. It was the clay we were started on. Getting some because it's cheap, to experiment. Maybe it'll encourage me to do deeper carvings since I won't be as concerned with the waste?
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