Babs

Epsom salts flocculates . Is that what you are after. Soda ash and sodium silicate deflocs..just saying

Underglaze whilst containing clay may contain other stuff. Slip is clay usually to avoid what Russ is writing about, it is mixedvwith minimum water and lhquified by adding a defloc. Darvan or sodium silicate. It is plastered on when pot is leatherhard, spritz the pot beforehand, and scrape the excess off when dried enough not to smear. You can stain the white slip with stains, prob a cheaper way to go anyway. Not sur wht look you are goung for or what glaze you are putting on top but maybe if hooked on slip trailing, onglaze decor. The way to go? If underglaze can be applied with slip trailer, too "liquid " unless pepared, as Russ states, go for "thixotrophic" searches.

@Min Not having read your posts closely, would a firing 100deg/ hr to 600 6hrs Then slow through to 800°, say, 80° /hr 2hrs. 20mins ish with a soak then 150°/hr to 1000°C 1hr 20min which gives a more economical firing schedule. Just thinking of a compromise to lessen electricity usage

Ha, one bag of that clay would make a lot of slip, just saying!-) Trade routes for centuries throughout , would make that authentic, right? Handluggage, right. For your face mask beauty treatment.

That's where your notes would help, eh?¹

Are you usng body stains or glaze stain ,or are body stains a thing of the past?

Way back when, folk bisqued to c08. I would say that If all is good at C04 why would one change to 04. It would be more economical to stay at 06 unless there is a problem there. I do what Pres does above BUT if someone comes by wanting an absolutely exact replica, glazewise, of a pot they bought a few years ago, I don't promise because as a potter, I don't need the exact same of anything.. ... . I appreciate the folk who do this, wondering now if @ Mark saw any differences in the pots that came home last month.

One at a time and take copious notes and photos. Test tiles or shot sized cylinders may save a lot of kiln space

Lots of slipware artists in UK atm, some very generous with their methods, check them out.

For the slip to fire whiter, you need to apply it a lot thicker. Applying slip to dry pot could / will cause a bloating of the slip away from clay body on firing. Your stencils will stick to the clay at leatherhard stage , depending on what they are made of. You could try a white firing porcelainous body as a slip .Need to use sodium silicate and test a few tiles for thickness and fit.

Pardon?:-))

@Pyewackette , ditto.

Better imo to apply underglaze when leatherhard, then glaze when bonedry , dry and fire through to glaze maturity. Pots turn out just fine. @oldlady single fires her pots perhaps she will chip in here. Quite comon , really. I learned the orocess and came uo caling it Raw Glazing, there are other names around.

Post a photo of what you want discussed. Makes it easier.

Yes, you have a wide firing range clay so I would be surprized if fully vitrified at lower temp of range. You may think of changing your clay into the future. clay and glaze maturing at Cone 6 or 7 would be a more economic and popular firing range. Google Midfiring glazes. Bisque firing is low at 950degC ,go for Cone 06, 1000degC , becoming more popular, cone 04, 1040 deg C.

A friend made an interior shell which fitted smack against the bricks then filled with packing matterial , this was to stop the bricks juggling and possible dislodging of the elements, it also supported the lid from inside if, that makes sense..may be overkill for you but with the roads around here, and distances travelled, made perfect sense

The glaze and clay. The clay needs to vitrify if being used for liquids and domestic use. The glaze has to "fit" te clay. The glaze you have, if fired to the temp which matures your clay, would probably run off your pots and ruin your kiln shelves. Lots of other considerations but that is th basics

But as Callie said ,you will not get the uniformity of colour and it may drop to bottom of glaze bucket

Hmmm, not sure, none dropping off the perch yet. Live in an agricultural area where run off from cropping land not the best. Poor soils also , trace elements, copper manganese and cobalt licks a spreading to promote healthy stock and plant growth, but I get your concern. Maybe I should use for fruit bowls, humans being a more abundant species.:-○. Being flippant here.

I have a friend who has a metal lathe and so has filings of copper, fine and not so fine. I have drizzled them onto the textured base of a birdbath, the texture is a swirl made by my finger across the base of the bath. It is first coated with a tin based white glaze and so the filings turn turquoisey green with black where chunky filing landed. I've thought of rolling out clay on some filings also and glazing with above glaze but haven't yet. Non functional stuff. Fun to play stimes. Some brass in there too.

Wow, you may be able to have a longer diving vacation! She must have loved your work. It is a bit humbling.Imagine if she could have visited your studio!

The wax will burn out way before the glaze starts to react to the heat process so should be good to go that way. A small band where glazes overlap may be an interesting transition... Let's know how it goes

If another firing sorts some of the prob, slow down your last hour of fitinv and soak at end. @Hulk sorted some issues. Spraying entire pot with asater prior to applying slip can help with a better evenness if application. Have you tried a white clay slip instead of engobe? Slip is different, as you stated engobe translates to slip in Sp. So perhaps try a slip. I use a white stoneware on a midfiring iron rich clay successfully. A "second" from my old stuff, don't make these anymore. White is reflection.

John Britt has free online videos in Youtube. Excellent teacher.

Keep them away from yur controller, dont think they like magnets. So they elease from the glazed ware ok?