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Salt.Forest

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  1. Hi all-- I'm making some ceramic bells, essentially the size of a wide mug. I'm planning on glazing the exterior but not the interior. Does anyone see any downsides to using a piece of kiln furniture that's taller than the bell to hold the piece off the kiln shelf? The top of the piece of kiln furniture would fit inside the bell and rest on the inside of the top of the bell. The bottom of the piece of kiln furniture would sit on the kiln shelf. The bell's only point of contact in the kiln would be the kiln furniture on an unglazed surface. I'm trying to avoid leaving the very rim unglazed. Any advice would be appreciated!
  2. Thank you all-- I assumed it was fine looking at other's work (for example: https://poepotteryshop.com/ols/all?sortOption=descend_by_popularity ) which look like underglaze transfers on raw clay. Maybe they just have a really low absorption rate...
  3. Hi there, I've recently begun experimenting with Amaco Velvet underglazes and am really enjoying them. If I have a foodsafe liner glaze on the interior of a mug, is there any concern with using only an underglaze on the exterior (with no clear on top)? Would it be dishwasher safe?
  4. Hmmmm...if I plan on using a custom program for firing (because of the aforementioned pinhole/blister problem), shouldn't I calibrate to that program? That's the assumption I've been working off of, at least
  5. Uhhhhhg I'm going to tear my hair out...I adjusted the thermocouple offsets, but now the cones bent even less. Is it possible that ditching the second slow cool ramp accounts for this, and I need to adjust the thermocouples even further? And yes, still pinholes/blisters, but fewer still.
  6. I know but there's a stubborn part of me that just thinks it should work with commercial glazes and a relatively basic commercial clay. I've probably got one more try in me, then I'll start moving to another clay body.
  7. Hi all-- Not particularly--they seem to be pretty evenly distributed. I did! Still not quite there but closer (top shelf on the left, then middle, then bottom)-- I'm going to adjust the thermocouple offsets a bit more dramatically. I was being a bit cautious because it seemed weird to need to adjust them so much with a new kiln. I don't currently have another white clay body I can try, but I was using a porcelain previously with some of these glazes and had significantly fewer problems --out of four bowls i had one tiny blister total, in an older kiln with a kiln sitter. For the glaze being too thick in the middle of the bowl--this is the second time I fired that particular piece, to see if the blisters improved with a different schedule. The glaze pooled quite a bit more in the middle of the bowl during the second firing. Still too thick? Given all the above I'm considering another test fire with similar temps but a adjusted thermocouple offsets (15 degrees for the middle and bottom shelf, 5 for the top shelf) and the below schedule: 100/hr to 220 400/hr to 2000 108/hr to 2185 (hold 15 min) Freefall to 2085 (hold 15 min) Any suggestions or tweaks?
  8. Okay! Thank you all for your suggestions and help -- I did another fire with a couple of test pieces and have some more answers and more questions. Answers to various questions asked by others: During bisque I leave the top peephole open I do think that this is largely a rutile glaze problem (though one of my non-rutile glazes had one tiny, annoying pinhole after firing). Refiring one of the blistered pieces--I would say maybe a slight improvement, but hard to tell. The outside definitely improved, the inside just changed blister patterns (see photo below) The new pieces fired with rutile glazes definitely had a less overall volume of blisters but still present (see photos below) I did adjust the thermocouple offsets, but not enough. Getting closer, but still need more dramatic tweaking I haven't used the L&L slow glaze, but at this point my programmed schedule is much slower than the pre-set program: 100/hr to 220 350/hr to 2000 108/hr to 2185 (hold 15 min) 100/hr to 2085 (hold 15 min) 150/hr to 1400 Questions: What now? I'm going to keep dialing in the Thermocouple offsets for accurate temps. In terms of blisters -- longer soaks? Soaks at different temperatures? Out of three pieces glazed without rutile glazes, one small pinhole total: New pieces with pinholes: Refired blistered piece, better on the outside, about the same on the inside:
  9. Thanks, Min! I'll give that a try. How long do you typically do the second soak for? I may have cleared out the final temp so I'll need to go check and see. In your opinion, this seems like a glaze schedule problem, not a bisque schedule problem, right? Amanda
  10. Hi all, I'm hoping for assistance with solving a persistent pinhole/blister problem. I am firing in a new L&L E23T-3 Kiln. In my prior kiln, I had experienced this same issue, but had a kiln sitter and much less control. Details: -Using Seattle Pottery Supply Alpine White -Using Spectrum Commercial Glaze -Bisque Fired to Cone 05 using the "slow bisque" program on first fire -- checked witness cones, it was more like a cone 06; adjusted thermocouple offset slightly, paranoid bisque fired a second time, this time to cone 04. Witness cones showed a 05ish. Figured that was good enough (obviously need to adjust my thermocouple offset further) -Glaze fired to Cone 6 using the below program with a slow cool with no holds--actual witness cones showed slightly underfired; (I only had cone 6 and 7 on hand to use, see photo below). However, these glaze are rated for Cone 5 to Cone 6 so it should have been fine. 100F per hour to 220F 350F per hour to 2000 120F per hour to Cone 6 (you can set a cone instead of a temp) free fall to 1900F 150F per hour to 1400 I've experienced this with other commercial glazes I've been using, and I'm starting to suspect it's the clay body. Am I missing something or should I just give up on this clay body--I have quite a bit of work made and ready to fire, but it's a bit discouraging to see this problem over and over.
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