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Michael D

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About Michael D

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  • Birthday February 4

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  1. I never thought of oxygen needing to flood the surfaces of the tiles. If in the future I grooved the bottoms of the tiles this might make a big difference as it would allow much more oxygen and sulfates to come and go..... Right now it is just the texture from canvas, probably not enough. Thanks!
  2. Hi, I make small tiles in my ConeArt kiln, Cone 6. For economic reasons I have been stacking the tiles horizontally, sometimes several of them-- with not problems for the bisque firing. They seem to be bisqueing fine. My question is: so long as the tiles are dry, and that the kiln has sufficient power, is there any reason why I shouldn't stack the tiles much higher, say 5 or 6 inches high? Especially if I leave an inch or so space around each stack? Thanks Michael
  3. Stephen. Do you ever come to a conclusion about Hydrocal vs Cermical? And the best rubber for the model? thanks Michael
  4. Yes. you are looking at the underside of the shelf just above (no more than 1" above) the tiles with the glaze that copper and other ingredients I listed. I hadn't noticed this before and these are new Corelites. The glaze has no more than 2% cu in it. Maybe a chemical reaction with the new shelves... Thanks
  5. I’m curious why, above and around certain tiles, in closely stacked shelves, there is a clear brown halo. The glaze in question has among other things, strontium, lithium and copper carb in it. It’s clearly coming from just that glaze. Any knowledge on this and if this should be a health concern? (I run a venting fan during the firing.) thanks.
  6. Thanks Min! I read somewhere that the B2O3 (or boron) should be at least .14 for Cone 6. But you say that I may have too much alumina in the recipe for this. Is Silica easier to melt than the alumina? Is that why you suggest I get more flux (or boron) in the recipe?
  7. Hello all: as I examine the specs on glazy, trying to make sure I have enough boron for a proper melt (trying to get at least .15, it’s not clear what these numbers mean (circled in pics). It looks like I am fine with R2O. But it’s the boron numbers that confuse me. How should I see/interpret these numbers? mike
  8. I'm blown away by your generosity of sharing knowledge and time. Thanks to all! I feel like I just too a crash course in glaze chemistry, etc. I see now that the original recipe may look cook, but it is clearly an underfired gloss that may not be stable. I've am seeing now how vital it is to have an understanding of the various tools: stull, R2O ratio, glass to alumina ratio, cooling rate.... And after that it is really about testing and verifying in my particular kiln, with my particular firing schedule. I'm still trying to figure out the R2O/RO ratio as that seems really tricky a
  9. Thanks Callie and Bille. That was an enlightening video, Bill. Thanks! I do a drop and soak, Cone 6 and the witness cone says that it fired nearly a full C6; (I have other C6 recipes in there that were gloss, and they turned out great.) Maybe it is a problem of slow cooling (many shelves with tiles). But again, the other tiles came out great. After watching this video, I think it's clear that I need more flux. or frit. Here is another question: I have no idea when looking at the Stull chart, and R2O, what the cone for the recipe should be. This helpful video says that Bor
  10. Hi. I'm pretty much a beginner with Glazy. When I enter a recipe for a very matte white into the Glazy recipe maker, it shows on the UMF chart and the Stull chart that it should be high gloss. I know it is matte because "matte" was the recipe of the original recipe and because it has made very matte glazes from my kiln. I wanted to experiment with entering into the calculator more frit, or more glass to make the glaze less matte and more semi-matte, but this is throwing me off. Could it be that this C-6 is really just an underfired gloss? That maybe I just need to add a littl
  11. Thanks for all of your advice! It sounds like 1" Corelites would be fine; And maybe even the 5/8" . If they warp after 50 firings, for example, maybe I could flip them or just replace them. And maybe I could strategically move the posts in a little-- say two inches toward center -- and give the shelf more support that way. Right now, if I place the shelves I have (which are modified 11x22"-- there is a good inch in there for clearance and fingers. I was originally going to use setters but because I am experimenting with different and small tile shapes it didn't add up. I figu
  12. Hello Ceramics Friends! I'm starting a small business that involves making smaller handmade tiles. I bought a really nice ConeArt 27" square kiln and had hoped to stuff it full with shelves on 1 inch posts, maxmizing the number of shelves per fire. I'm only a half year into this and it is clear to me that investing in alumina shelves (3/4"") was not wise as it seems like half my electricity is spent in heating them up (and a half day longer waiting for them to cool down). I would love to buy a kiln full of advancer shelves-- the weight, the thinness-- but I just can't afford that rig
  13. I know that overfiring clay, say a terracota to C6, can cause the body to bloat, etc. But besides burning out colors, or perhaps creating a mismatch with a body intended for midfire, is there any fundamental problem with firing a lowfire glaze way beyond its intended cone? thanks Michael
  14. Also, (sorry to hijack this thread). My daughter made her first mugs (dark clay) and wanted to gift them to friends back at college. She is leaving soon and I don't want to rush it and ruin them. But I also need to have them finished by this weekend. If I fire a clear glaze on them and the glaze comes our with too many bubbles (making it opaque), is all lost? Can I fire it again and, say, soak longer, to clear the bubbles? I'm planning on brushing on the glaze very thinly this time. And slow firing it to C6 with a soak at the peak, and short soak coming down. Michael
  15. Thanks Neil! Will do. I also think that I was hasty in mixing my first test glazes, not sieving enough, and brushing them on too thickly, The glazes all looked great on a white body, but on the dark 710 (which I love) they look horrible. (Which makes me think it has something to do with escaping gases from the body) Michael
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