Babs

That is really disappointing. Good luck with the glazing!! I would do a test piece, may save you futile hours of underglaze and glazing not to mention the expense of the material. Heating the pot prior to glazing may help but ...... Can't believe a professional establishment made this 101 firing mistake! Did you have a full kilnful?

Nowhere do you state the clay you are using. On the box , bag it will give a firing range. This will determine what cone you fire to. Cone determines heatwork done, thus the cones placed on each shelf to indicate what happened on each shelf. So a fast firing may reach temerature but not had sufficient heatwork done to mature the glazes. You will have many aaaah moments. Enjoy! If making functional pots, the clay needs to reach the upper level of its firing range to be vitrified sufficiently to retain any liquid placed in it. Do take lots of notes and ask many questions. So much to learn in this field.

1100C is about cone 03. Too high for bisque imo Cones are numbered with a 0 in front of numeral which diminishes (as a neg maths does ),as the temp rises until 01 then cone 1, 2 as temp rises. Most folk bisque to 04 these days but depending on clay body, 40 plus years ago folk bisqued to cone 08. Be clear of this when ordering stuff and bisquing glazing. Good practice to place banks of cones on shelves to find out what is happening in your kiln. Keep log book of your firing and results.

Ok, Bisque cone 6. Way too high. Pots wont take the glaze, they will not be porous enough Bisque Cone 06 to 04. Some great books around, bibles. Where are you firing your stuff. If testing, ie noting down what you put on what for future reference, make test tiles or put waster biscuits of clay under each pot , can be reused, in case glazes run off your pots. Test tiles a must really.

How are you measuring rhe temperature or cone yourvkiln is reaching? Cone 06 will need to reach about 100degC . 2 hours to reach 1000degC would be an amazingly fast for any pot or glaze to reach maturity. And would get nowhere near that temp on low. Research on thIs forum firing schedules or ramps. You would have a pyrometer?

Also seems to be random brush marks on the pots and on the rim. If doing slip work and clay is already too far past optimum dryness the spray the entire pot before adding slip ti try to even out moisture. If you could find/make a chuck to support your mugs when applying handles and sprigs, that would remove accidental pressure on part of pot not beingvworked on.

You say you removwe part of the plastic after 3 days. This would lend itself to uneven drying. Bath, England, summer noe, air hotter and drier , wind across pots?

Are you drying pots on rims? Best to flip as soon as firm enough. Poss damaging pot when applying sprig and handles...wetting pot too much when applying sprig? As Min writes, give us the step by step.

You could glaze a fair amount of that rim. Put bisqued lid in place. Run a pencil around to mark where it sits on rim and wax only the area required. Your glaze looks stable enough to do that.

Check out mitchiburgceramics.

https://www.instagram.com/p/CeRYGg0pCdp/?igshid=YmMyMTA2M2Y= Example.

Let's sèe the results! Maria Martinez cow pancakes wouldn't get much above red heat.

Wow!! Very generous!

https://www.instagram.com/reel/CeKLGsAl10y/?igshid=YmMyMTA2M2Y= may help

Look at the black potas made by Maria Martinez and her people and their method. Fired outside to be sure but the colour of the fire, animal pancakes, would lead me to believe it would be no higher than low 900 or lower....

Ok you will replace, but not free of charge? I thought you were giving him a freebie. Inless the mug cracked when filling with boiling water, I wouldn't be replacing anything. I have been approached re handles dropping off and on inspection it appeared that the mug was handled roughly, no pun intended! Reasonable, common sense and courteous manner usually wins the day.

Why are you replacing this one? How long since purchased?

Why do you think the sitter is broken? If the seller said no sittef and it clearly has, the sitter could be right as rain. You can insert a timer so electricity cuts off your kiln, may be cheaper tha new sitter. Once you sort how long your firing takes, set your timer for about 30 mins longer than expected firing time. Sitters should not be expected to work. i.e. don't leave to turn off as set. Be around for expected turn off.

Looks like the base is much thinner than wall of pots so this would contribute to problem. When are you cutting the hole in the base?

Search these forums ,there has been a lot written up on these issues

Wow ,A process or two but lovely end result. Do you sculpt and make molds for own sculptures too?

I sprinkle copper filings onto plaayters and bird baths. A blck/ green speckle obtained . By size of those strips may be black metallic with green but would be dependant on underlying glaze. Mine had tin as opacifier

Set yourself an slarm about 30mins after expected finishing time. A log book for each giring and results really important into the future. Get the rate of rise in temp/ hour and then you knIw when to set alarm for future firings. Some examples of folks log books in these forums.

Take care. What about the person who uses Ferrous Oxide? Gets nice results

Try dm a forum member @Marc McMillan He has great album on Ferric Chloride pots . Do a search Ferric Chloride in this Forum.