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Found 7 results

  1. Hello, I am a new member (and new to pottery in general) and have struggled to find the answer to the glaze defects I have been experiencing on previous posts in this forum. I am having trouble with pinholing/pitting/airbubbles (not sure exactly what to refer to it as). Most of my glazed pottery either has loads of little holes (this is especially bad with black underglaze topped with clear) or lots of tiny bubbles trapped beneath the surface. To provide a background, the clay I have been using is Scarva Earthstone ES5 Original White Stoneware Clay, which has a firing temperature of 1200-1290°C and some grog in. I have primarily been using Amaco velvet underglaze, which I apply on cone 04 bisqueware and top with Amaco clear gloss (HF-10), before firing to cone 6 on slow. I only use the standard programmes on my little Skutt Firebox as I have not figured out setting up my own yet (i.e. with soaks). Using tips from previous posts, I have tried wet-sanding bisque fired pieces before glazing, and making sure they are washed and dust free. I have also experimented with slow firing vs medium. The sanding helped a lot and I have fewer pinholes now, but am still getting loads of tiny little pits on (specifically) the black underglaze. I am not sure why this is different to the other colours or clear gloss over bare stoneware (but this still has lots of airbubbles underneath, they just aren't breaking the surface). I have attached some close-up photos of the issues, which hopefully are good enough quality to be visible. I am not sure what is causing this and would be really grateful if anyone has any ideas? Thanks, Ellie
  2. Hi all! I’m new here I’ve thrown lots of ceramics over the years, as a student in a classroom setting (so, lots of ceramics classes where someone else loaded & fired the kiln, haha), but am brand new to firing my own kiln. I recently set up a studio off the side of our garage, and acquired a used Duncan EA 1020-2 manual kiln. I bisque fired about 25 pieces to cone 06 with no obvious issues; firing took about 10.5 hours with top peep hole open (I don’t have a vent, so needed oxygen to enter the kiln in some way - figured leaving a peep hole open was the best option?). I bought several pints of Amaco Potters Choice glazes (blue rutile, oatmeal, chun plum, lustrous jade, and 3 or 4 others), and did lots of reading/searching on these forums and other sites, and gleaned that in order to get bright colors with these glazes, you must brush on many layers, quite thick; so, that’s what I did. Glaze fired to cone 6, with a small cone in the kiln sitter. I did not have witness cones (I very, very much regretted this almost instantly, but as I’m brand new to firing, I wasn’t aware I needed them when I was ordering all my initial supplies, so I had none), but around hour 12 I began to worry that something...wasn’t right, because of the time elapsed. The cone 6 glaze fire took 16 hours before the kiln sitter triggered and only reached temp when I finally plugged the top peep hole. I let it cool overnight and opened this morning, to...major disappointment. Very dark glazes, browns and dark greys, some purples but those were all very dark and almost matte looking. Tons and tons of pinholes, as well, which are new to me - I’ve read that many things can cause them? Without guidance cones I know there isn’t much to go by, but I suspect the kiln overfired, due to the very dark, less than stellar glaze results and the time it took to finish - could overfiring lead to these results? Or does anyone have any insights, helpful recommendations, encouragement? I know it happens, especially in the beginning, but I’m still kind of bummed. Thank you all for your help! -Kati
  3. Hello, My white gloss glaze has recently started pinholing I believe. We have been using it for years with no issue. i initially started with the kiln it is firing to temp. We fire slow bisque and slow glaze programs to 06 and 6. I have tried bisquing to 04 with a hold on the end but the defect came back... I have tried a hold on the end of a glaze firing (20 minutes) with little improvement. We have tried the ware with this glaze in 3 different kilns all have the same problem especially on larger ware. We have also tried wiping down the ware lightly with a sponge on both sides did not help. I am thinking it must be the glaze. But I have no idea where to start. Help.
  4. From the album: USB Images

    Pin-holing from high feldspar content in clay body.

    © TJA 11-2017

  5. From the album: Ceramics Fall 2016

    Turquoise stone and white matte ^6 ox on calico dark red clay. A couple very wonky vases that developed decent sized cracks from uneven drying, this was one of the first things I made after taking a hiatus of 3 years from clay, be gentle! I needed to keep a few unsatisfactory pieces to try my experiments. I am totally head over heals in love with the color combo, but am very sad all the pieces developed pin holes on them... I talked to the professor and she is going to go over how to avoid that next time and keep my work together as to have a more consistent firing.
  6. From the album: Ceramics Fall 2016

    Turquoise stone and white matte ^6 ox on bone white clay. A very wonky vase, this was one of the first three things I made after taking a hiatus of 3 years from clay, be gentle! I needed to keep a few unsatisfactory pieces to try my experiments. I am totally head over heals in love with the color combo, but am very sad all the pieces developed pin holes on them... I talked to the professor and she is going to go over how to avoid that next time and keep my work together as to have a more consistent firing.
  7. From the album: Ceramics Fall 2016

    Turquoise stone and white matte ^6 ox on bone white clay. A very wonky bowl, this was one of the first three things I made after taking a hiatus of 3 years from clay, be gentle! I needed to keep a few unsatisfactory pieces to try my experiments. Ended up loving the combo, but am very sad all the pieces developed pin holes on them... I talked to the professor and she is going to go over how to avoid that next time and keep my work together as to have a more consistent firing.
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