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Brandee Ross

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About Brandee Ross

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  • Birthday 06/05/1978

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    Ann Arbor, MI

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  1. I had a successful glaze firing. I added the downdraft vent (still using the overhead vent also, helps with wax fumes and ambient room temperature) and went back to my original firing schedule. I changed the hold from 20 to 16 minutes with better results, and then finally to 10 minutes with the best results. Thank you for everyone's thoughtful advice and help. I appreciate all of it!
  2. @GEP I use a lot of wax resist so I'm actually thinking of using both vents, but with the overhead raised up at the max 4" (or slightly more). The overhead vent definitely makes the room more comfortable to be in than the downdraft alone, both in terms of smell and temperature. I'm dying to know the answer too, because this is my busiest month of shows and it's extremely stressful not having enough inventory to make those fees worthwhile!
  3. @Joseph F the change in cone was from trying the new schedule. When I fired my usual schedule there was only a minor difference in heat work in the two vent systems. I asked Vent-a-Kiln about the oxygen and they assured me I wouldn't notice a difference... but they were trying to sell me a vent, ha ha! I ordered a downdraft vent yesterday so I'll hold off doing any more firings until it's installed. The problem started before I replaced the vent but perhaps it was due to wear and tear; the old downdraft was pretty beat up when I replaced it. That top peep is always open during bisque but maybe the overhead isn't getting enough fresh oxygen into the kiln. @Min I will also try another body; the clay I'm using is Rovin's most popular: https://rovinceramics.com/collections/white-moist-clay/products/ro-14-light-stoneware They also carry a few Laguna varieties so I'll give that a try.
  4. I posted images with the green glaze, but I am having the same defect on all my glazes and some of them use a different base: Licrorice Mod 4 (MC6G) Ferro Frit 3134 26.00 Custer Feldspar 18.00 Talc 5.00 Whiting 4.00 Ball Clay 25.00 Silica 22.00 ADD Red Iron Oxide 9.00% Cobalt Carb 2.00% Bright Sky Blue (MC6G Glossy Base 1) G-200 Feldspar 20.00 Ferro Frit 3134 20.00 Wollastonite 10.00 EPK Kaolin 20.00 Silica 18.50 Talc 11.50 ADD Cobalt Carb 1.00% Red Iron Oxide 0.50% Rutile 6.00% French Blue (MC6G Glossy Base 2, same base as Rutile Green) Custer Feldspar 22.00 Whiting 4.00 Talc 5.00 EPK Kaolin 17.00 Silica 26.00 Ferro Frit 3134 26.00 ADD Cobalt Carb 1.00% Rutile 4.00% Raspberry (Van Gilder) Nepheline Sye 18.00 Ferro Frit 3134 14.00 Whiting 20.00 Ball Clay 18.00 Silica 30.00 ADD Chrome Oxide 0.20% Tin Oxide 3.80%
  5. Mea, I think this may be my issue. I tried GlazeNerd's schedule and it actually worsened the problem. With the new program, I got over 50% loss but bent a perfect cone 6 on all shelves. I suspect my flaws were isolated bubbles/blistering that was exasperated when I switched from a downdraft kiln vent to the overhead style (a little more heat inside the kiln). My earlier firings were more like cone 5.5-5.75. The clay is rated to cone 8 but I guess that doesn't mean it has to like it.
  6. I also double sieve with an 80 mesh before every glaze session. I think what you are seeing are flecks of the black glaze. The bowl was dipped in the Rutile Green, then waxed, then MC6G Mod 4 Licorice applied. The second photo is the inside of the same bowl.
  7. Oldlady, the problem I want to correct shows more clearly in the first photo. There are some similar blemishes on the inside but they are less noticeable. The spotting you refer to is not a defect. In fact, I really love that effect. It happens when I put my black glaze over the rutile. I think it's due to the high amount of iron oxide in the black glaze, sort of like what happens with oil spot glazes. The stripes are just wax resist. Here's a commercial glaze series that produces the same result: https://www.coyoteclay.com/TwoStep.html
  8. Is it possible that my manufacturer's raw clay materials have just changed a bit in composition over time and that is why the problem seems more prevalent now? I sometimes have both types of pinholes, but for the most part I can see down to the clay. I will try the new schedule when my bisque load completes. I cannot thank you enough for generously sharing your knowledge!
  9. My current glaze program: 150°/hr to 250°F 400°/hr to 1676°F 120°/hr to 2167°F 18-20 minute hold, off So my new program would be: 150°/hr to 250°F 400°/hr to 1676°F 108°/hr to 2167°F 18-20 minute hold 999/hr to 2100°F 10 minute hold off Is that correct? Maybe I should go a little cooler than 2100°F since I'm only going to 2167°F, maybe more like 2067°F?
  10. Bone dry: I don't rush my drying. I would say most pieces take at least 4-5 days to reach bone dry, longer if I leave them under plastic (handles and other attachments). I spend 4-6 weeks making a new cycle of work so work could sit out for that long before being bisqued.
  11. This is a problem I have had intermittently since I started making pottery at home in 2010, and lately it seems to be happening to more pieces each firing. 1. Are these pinholes or blisters? Sometimes they are sharp on the edges. 2. How can I correct this? Helpful (?) details: I am doing a slow bisque firing to cone 04. I hold for 10-15 minutes at peak depending how tight I've loaded the kiln. Bisque firing profile: 80/hr to 250F, 200/hr to 1000F, 100/hr to 1100F, 180/hr to 1676F, 80/hr to 1945. Glaze firing to cone 6. I do a programmed "slow" firing on Bartlett controller to 2167F and hold for 15-20 minutes depending on load. Witness cones show cone 6 achieved. Stoneware clay, made by a local manufacturer (all-purpose Goldart-based body rated cone 6 to 8. Contains 4.5% fine grog). 10 cubic foot kiln, electric Kiln is vented with a Vent-a-Kiln hood that is only 2 months old, replaced broken downdraft vent. Problem occurred with both vents. Trouble occurs sporadically with all my glazes, which I mix. The green glaze recipe in example photos: Rutile green: Talc 5, Custer Feldspar 22 Whiting 4 Silica 26 EPK Kaolin 17 Ferro Frit 3134 26 ADD Rutile (light) 6%, Copper Carb 4% Happens on all types of work: mugs, bowls, etc. I've read on the forum about correcting pinholes with a slower bisque but I feel my firing is pretty slow already. Do I need to slow it more? Why does it only happen to certain pieces? Sometimes two identical pieces glazed and fired at the same time in the same way result in one unblemished piece and one as shown above. Working from home on my own and really feeling out of my depth... and incredibly frustrated.
  12. I recently changed from a downdraft Bailey kiln to an overhead Vent-A-Kiln. I work with a lot of wax resist and the vent hood is doing a much better job of removing fumes. However, the old vent mounted to the back side of the kiln and there is a hole (similar to other type of downdraft kilns). Work too close to this hole is not getting fired properly so I'd like to close it up. What would be the easiest way to accomplish this?
  13. I have been getting mine at Highwater (http://highwaterclays.com/). Mobilcer-A is still going to be produced, right? My work is 100% dependent on it.
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