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tomhumf

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About tomhumf

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    http://www.thelittlepotcompany.co.uk

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    Sheffield, UK

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  1. I did take your previous replies on board however - I've been continuing to fire reduction with tape on burner ports, as I can't get rich yellow flames just with closing the damper. I don't know if it's my kiln design or what...but closing damper enough for yellow flames means temp starts to drop - I can't increase gas anymore at this point. I'm actually getting a little too heavy reduction though overall by reducing hard at 900C for one hour, with 4 of the burner air holes taped. I'm wondering the best option for lighter reduction. If I reduce without the tape on burners
  2. I've been struggling with this glaze for a while. Firing to cone 7-8 in reduction with speckled stoneware. I'm aiming for a silky matt smooth surface, which happens occasionally and on small test tiles. https://glazy.org/recipes/119355 The worst example shows the base of bowl, it's like the iron in the clay is poking out, surface feels almost like sandpaper. There's lots of very tiny pinhole / bubbles - not sure how you'd describe them. I seem to get better results where I think the tests were hotter ( inside of dish), but I can still see some similar surface imperfections.
  3. I made a similar kiln, not sure the thread is updated to what I do now. I use a brick on the top of chimney as my damper . I fire in oxidation, reduction then neutral. I get probably within half a cone top to bottom.
  4. @liambesaw ok thanks. Maybe I'll just run the emptier tanks on their own to start firings, and pigtail the fuller ones when I need the extra volume.
  5. They are 47kg tanks. I have a thread about my kiln, don't think it's the one you mention though, it's a 10 cubic ft internal space running on one burner. It's about 12 hours firing. Probably not half inch of ice actually, but very icy. I may be able to reduce gas usage in future, still working on my glaze schedule. I don't have a problem with icing tanks when bisque firing for 12 hours. Nobody responded to my question about if the gas would equalise between tanks if I connect them together. I've watched a couple of videos about propane valves and it seems they would work both ways, so a
  6. Hmm, they don't shut off, I just start to loose pressure. It's running at about 1.5bar in reduction. It's not just a freeze line, I get about half inch of ice building up by the time I need to switch, over half way up the tank. I thought linking them would mean half the gas used from each one so they would freeze up half as quickly.
  7. I get through quite a bit of gas firing my kiln with one burner, the tanks are freezing up while they are still half full. It's not really practical to run water on them. I think if I connect two together they will stay thawed for longer, I'm not sure the best way. I've found this connector , which I would use with my existing regulator connected after the T junction. https://www.ebay.co.uk/itm/New-LP-Propane-Gas-90Cm-2-way-Hose-Connector-Coupler-of-Two-Gas-Tanks-Acme-Nut-/264275507385?_trksid=p2349624.m46890.l49292 May be stupid question, but do the valves on top of tanks only
  8. Thanks Bill, I did try initially to reduce with just the damper. It seemed to not work very well, i.e loosing temp or blue flames from the spy holes. I'm right to think blue flames would give bad reduction? Maybe I just needed to crank the gas more or something. I did have positive pressure during the hour reduction - yellow flame from bottom peep. I can see you point about keeping above neutral for the later stage. I was a bit worried about having enough gas in this case so wanted to make sure I completed the firing.
  9. I just wanted to update this thread with my latest results. I have been using the kiln mostly just for bisque firings since I last wrote - these have been going fine. The previous glaze firings didn't turn out very well - didn't really have successful reduction. I've read a bit more and found this article really helpful http://ceramicsfieldguide.org/pdf/val-cushing-handouts/special-extras/Cushing-HighFireProcess.pdf Using that as a guide I started getting great results from my other tiny kiln. Basically oxidised to start, reducing hard @900C for around an hour, then firing in
  10. I've only been full time for around 6 months but it's going well so far. It sounds like you don't need to worry about making speed, I think I throw slower than that. Like others have said it's all the other stuff that sucks time. I start to finish about 50 pots a week, they are mostly customised so take longer to finish than plain pots. I sell everything online , for me getting my dispatch setup efficient was key. I used to spend ages sorting labels and taking everything to the post office, waiting in cues...Now I've got some dispatch software that combines my Etsy and Shopify orders in
  11. Bill - I do fire to cones and temperature, it was only hitting around 1210C with cone 7s down before. I've done two firings since posting this message. Both times I've got kiln up higher in temp - around 1230C and held for 30mins. The cones are very melted, it might be nearer cone 8 now. All pots so far have been problem free, glaze is a bit shinier, so it must just have been underfiring before I think. I do prefer the more Matt look. I may try increasing clay, reducing quartz with new firing style. I'm not sure if that might bring this problem back though.
  12. Hmm top temp could be an issue. I usually only get up to around 1210C which I know is low for cone 7, even though cones are well melted. I did hold for a half hour at top temp in this firing, and downfire to 1100. I don't fire super slow - around 8 hours so not sure why top temp is low. I bisque fire in a larger gas kiln, its about 12 hour bisque with 3 hours between 700C and 900C.
  13. Thanks, I always use the same clay and bisque fire. I fire to cone 7, but it's a little gas kiln so it could be temp differences. I guess more frit then...
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