TaraB

The witness cones were bent as normal too. I think I may have thought of a possible cause... The update is, the paper towel became slightly damp, which suggests porosity. The mugs also dried completely streak free after a few hours (they look normal!)... again, suggesting porous glaze. Then I remembered that the glaze I used was nearly empty. I used the very last drop (brush on clear glaze) and then finished the last few mugs with a new batch of glaze. I have no idea which mugs had the old versus new glaze but I am wondering if I fill them all with water, I may find there are a couple that don't streak. I guess its worthwhile testing this theory tomorrow if it means I may be able to save a couple of mugs. Not sure if this theory is right but maybe the composition of the glaze changed or it became too thin as the glaze/container ran low. I am assuming I cannot sell the porous mugs?... They aren't microwave safe due to the lustre but will they stain on the raw base overtime and possibly lose shape? If so, they might just have to find their way into my own personal mug collection lol. Thanks again

Re-Fire*

Thanks for taking the time to reply, Bill. I see what you’re saying with the glaze… It’s just odd because I’ve used this same glaze several times before and never had this issue. It’s not a stain as such, because I get the same streaking in the remaining mugs with plain cold (or hot) water. It does seem to be a vitrification problem. I have had them filled and sitting on paper towel for the past few hours and I’m starting to notice very slight dampness on the paper . Unfortunately I cannot retire them as they have gold lustre which I am assuming will not do well in hifire!? Can batches of the same clay vary? ie, could this particular bag of walkers 10 be slightly different to my previous bags? I am so stumped as to why this has happened.

Hello! I've just made a new batch of mugs fired to cone 7. (It is walkers stoneware 10 clay which can be midfired ^7-8 or hi fired ^8-10) . I made a coffee in one so that I could do some product photography, however once I tipped the coffee out there were streaks of discolouration on the inside of the mug. Initially I thought that they may be non-vitrified, so I poured water into several of the other mugs and the same issue is happening. My question is why would these be non vitrified if the correct cone was used and the sitter dropped at the right temp? The firing was no different to any other...? The only new thing I have done with these mugs, compared to my usual firing, was add a gold lustre. I read something about poor ventilation during a lustre causing 'smoking' to the ceramics but I'm not sure what that actually means. I had both peepholes open as well as the top vent hole. I was so excited to launch these mugs but now I'm unsure if they're fit for functional use. Please let me know if you have any ideas what may have happened and if its possible to sell these mugs! Thank you kindly. Images show before liquid (no streaks) and after liquid (streaks). Tara

This has been very helpful. Thank you Bill. Most appreciated. I will re-fire them to bisque temp tomorrow. Kind regards

Hi Bill Thanks for your thoughts on this. Is there a chance I will over bisque them by re-firing? Or it doesn't matter how long it sat at 400C as long as they didn't go over cone 04..?

https://photos.app.goo.gl/474ka3s43GgBZ2jS7 - not sure if this is of any help. A quick video clip of the tinking sound of the undebisqued pots.

Hi Everyone, My kiln started playing up a few days ago whereby the relay kept arcing when set on low setting (Duncan teachers plus). This started within a few minutes of the bisque fire so I shut the kiln off straight away and called a technician who advised I would need a replacement relay. Aside from the relay issue, I later realised on the same day that I hadn't completely turned the kiln off. The lower elements appear to work constantly when the toggle is on OFF when the sitter is engaged/on... and I hadn't disengaged the sitter. As soon as I realised my kiln had been on the whole day (approx 10 hours), I measured with a pyrometer and it was sitting at approx 400 degrees celsius. What would you suggest I do with these '~10hr 400degrees fired' pots now? They appear to be somewhat bisqued (they make a tink sound when i tap on them) but they don't have the usual 'very pale pinkish tinge' that i get with my bisque ware. Should I just go ahead and glaze them or is it best to refire? (I intend to dip glaze some and brush glaze the rest). Since this is a full kiln of paid orders, I am scared to lose all this work. I am thinking to try glaze a couple of the pots tomorrow and do a glaze firing to see how they come out,... but if anyone has a more expert view on what to do, I would most appreciate your input. If i can potentially go ahead and glaze fire the whole lot tomorrow based on anyones expertise, that would be ideal for cost and time saving! I promise not to hold anyone accountable for the final outcome :p Thanks heaps! Tara

Thanks Bill! Thankfully i was able to source one from the lovely team at industelec - Blackburn (..future reference for any other melbournians that may need their assistance). Tara

Hi Melbourne friends, I am hoping someone might be able to suggest where I can get a replacement relay for my Duncan Teachers Plus kiln? I need it asap so I am hoping to find one in Melbourne, AU that I can pick up in store versus waiting for postage from interstate. Thanks

I am crossing my fingers the elements don't need to be replaced, but I'm not holding my breath. I have a Duncan kiln which fires to cone 8 but it has little ability to manually control and I find it fires too quickly for bisque. In saying that, I'm not sure its worth spending hundreds of dollars on replacing the elements for the Tetlow (they're about $250 each here in Aus.) just to gain a slower bisque. Hmm. I guess I will make that decision once I know if its necessary to replace them. Thanks for your help. Tara

Hi Bill, It is tricky to read but I'm sure it says 4.8kw which i think is how it originally comes. It's single phase, 240v, 20 amps. Tara

Hi Neil, Thanks for your reply. The bricks aren't loose at all on the roof or the door. There's only a couple of loose ones around the edge at the front. Unfortunately, I won't know if the controller works until we get the plug fixed and are able to switch it on. Thanks

Hi All, I am a newbie to this community, but I was hoping someone might be able to give me some advice whether or not a secondhand kiln I have acquired is worth investing to restore it. It is a K6 Tetlow which was sold on behalf of another seller, therefore there was very little information about the kiln available. It doesn't have much/any accessories but I picked it up for good price, so I thought it was a gamble worth taking. The plug has been cut off, so I will need to get that fixed before anything else, but what I am mostly concerned about is the overall structure of the kiln, and whether it looks too rusted/worn. I would really appreciate any advice. Thanks in advance, Tara