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tomhumf

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About tomhumf

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  • Website URL
    http://www.woodseats-pottery.co.uk

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  • Gender
    Male
  • Location
    Sheffield, UK
  1. Ok Marcia I will try that trick with some of the worst offenders. I've taken your advice and ordered some 03 cones to fire to 04 Neil. It's occurred to me that the worst offenders were saucers and bowls I'd stacked with sand between them during the bisque. Maybe this contributed to the problem, and I might just bisque everything separately in future. Thanks both for your suggestions.
  2. I've just unloaded a glaze kiln and have quite a few pinholes. They are worst on pieces I have done two layers of glaze on. Some things are fine but some with just one glaze on have pinholes. It's the same clay and bisque firing. The clay is a heavily speckled stoneware, and I'm thinking I haven't been bisquing high enough. My kiln sitter kiln fires one cone lower than the cone you put in the sitter. I've been using ^07 bar thinking I'm doing a ^06 firing, but of course it's actually ^08 ! Duh So reading other threads I think I'll get some ^02 bars to fire to ^03 and get some witness cones to check. My main problem is I have a set of pots that I bisqued to ^08 that I really need to turn out nice. Would it be ok / make a difference to refire them when I get the new cones? Thanks!
  3. Ok thanks Marcia and Marc. My studio is an old external garage with no insulation, and ground level halfway up the walls on two sides. It's damp even in summer. I need to take ware in the house to dry fully. Since I only manage to do a couple of hours every other evening its actually not too bad having slow drying.
  4. Thanks everyone. I guess I will try using a bit more clay, and try putting a footring on. How thick would you say your bases are after trimming Mark? And how much clearance do you have between the footring and base?
  5. They were thrown to 30cm diameter from 2kg lumps, the bottoms are as flat as I could make, around 1cm deep thrown. I cut them from bat straight after throwing, then trimmed a little off bottom leaving about 0.5cm thickness. They are stoneware. The bats are plywood, about half inch thick. I have seen your plates during reading about this - very nice.
  6. Marc, I posted that before I saw your reply... I will answer your questions..
  7. After doing some more reading I guess it's the rims drying faster then base which causes the lifting. Does everyone cover their rims with plastic?
  8. This is a two part question. I've not made many dinner plates, but have a set of four drying currently that I have trimmed. I have quite a damp studio/ garage so things dry slow. During drying some of my plates lifted in the centre. I've now put some weights on them to counter this. These ones have flat bottoms - no footring. I've had the problem before. So firstly is this lifting of plates common, if so how do you avoid it? Maybe it's the way I have trimmed them. And secondly do you think footrings are better than flat bottoms - may this be the cause? If I trimmed footrings without any nubbin / centre support I wouldnt be able to weigh them down to prevent lifting really. Otherwise the weight would push the centre area I would need to leave free for glaze onto the shelf...
  9. My hydrometer is labeled from 0 to 70. My glazes vary between 40 and 50 on my scale. 40 is about like skimmed milk so I guess it's just shorthand for 1.4 or 140 yes. I usually do about 3 or 4 second dip for one layer glazes, I bisque to ^06. I tried doing two layers tonight. The first trial was with the glazes my normal thickness. I thought this looked a bit thick so thinned them out a bit and did a second test. Looking at them now the first test looks better. I just waited until they were touch dry in both trials. I'm still seeing some little bubbling but not as bad as I've had previously.
  10. Oh, what about glaze thickness, do you use them more watery or just the same as single layer glazes?
  11. Oh wow, I'll try it later, never thought of doing it straight after. Thanks everyone
  12. I've recently been experimenting with layering glazes. I've been have trouble getting a nice glaze thickness and smoothness. When adding the second glaze it often has loads of tiny bubbles and goes on really thick. Should I be thinning the glazes out a lot more than if I'm doing single coats? They are currently around 40 specific gravity which has been about right for when just firing with one layer. I'm also not sure if the first coat should be bone dry before adding the second? I left it a day, but my garage is quite damp and cold. Thanks!
  13. I too use cones in my electric kiln sitter kiln. When I got the kiln it was firing 2 cones below what it should be. By using witness cones I've been able to adjust my kiln sitter mechanism to compensate. I think they are good piece of mind, and a helpful judge of when the firing is nearly complete for us who don't have digital readouts.
  14. Mostly just spiders in my studio, and me occasionally
  15. Had to move most of my house into the garage studio due to home improvements, no throwing for a few weeks :(

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