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shawnhar

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Everything posted by shawnhar

  1. Feeling a bit lost on my test results so far and looking for feedback please. My first glaze fire was fullish kiln load ^6 with 10 min hold and fired hot, 6 cone was drooped down on the shelf and I'm guessing was a soft 7. The glazes were pretty smooth but still kinda bumpy. Second firing was fullish kiln load ^5 with 15 min hold Med speed and fired hot I think, 6 cone was bent all the way over tip touching the shelf. All glaze was riddled with acne, little bumps with a hole in the middle Third firing was mostly empty kiln, used all the furniture I have and most of the shelves to add some mass but still a lot of empty space. Fired to ^5 with no hold Med speed. 5 cone bent over tip touching shelf and 6 cone bent 30 degrees. All glaze has the acne, not as bad as the second firing but still there. Fourth firing kiln loaded exactly the same as the third, but fired ^5 FAST speed, no hold, 5 cone bent over tip touching, 6 cone bent over 90 degrees. I thought running a fast glaze would create less heatwork and the 6 cone would be bent less, but that's not what happened. The pot on the top shelf is riddled with horrible acne, BUT, the pot on the BOTTOM shelf is way better, the acne is still there, but almost completely healed over (at least compared to the top pot!). I am hoping to understand WHY the acne is better/worse in each of these tests before I use a custom program for my next test. It "seems" like the more heatwork there is, the better the glazes are coming out, but that means I am firing more than a full cone over what they are firing at the studio just to get a smooth(ish) glaze, which is confusing.
  2. I will see about getting some welding glass, thanks! Tried the following schedule: Ramp Temp/hr Temp/hold 1 100 220/0 2 350 2000/0 3 120 2050/0 4 108 2150/10 5 -120 2050/10 Moving in the right direction but still pock marked, refired pots from previous firings were "better" but not healed. Pot on the bottom shelf is "almost" good, top shelf still riddled with holes but they are much smoother than previous. Not sure if I should increase the top temp or add more hold time. Even with a peak temp set well below ^5, it's still starting to bring down the ^6 cone.
  3. Hahaha, I wasn't sure it was blisters or pinholes or pitting. Read up on blisters and assumed that is the issue, created a schedule that slows down around the peak temp and started the kiln on lunch yesterday, it's now at 400F and I took a quick peek, cones look perfect and I didn't see any blisters. Fingers crossed! I have tried to look in the peepholes but I think my vision can't detect such a low contrast, once the kiln gets above dull cherry I can't see anything. I do only have one thermocouple, put cones in the bottom this time to see the difference, and a few of the blistered mugs to add mass.
  4. I have ruled out the clay, bisque fire and glaze by mixing pots fired at the studio and home. It is def an issue with my fire at home. The last piece I picked up from the studio was bisqued at home and fired there, came out with no blisters using that same turq glaze. Pretty sure the issue is the ramp up/cool down of the last 200 degrees, but the way my 6 cones are bending over is confusing and I'm not sure if I should be firing to a lower temp and a slow climb/cool around the peak, and what peak temp to use.
  5. Well it's been 6 months since I started going to the studio, things are moving along quite nicely I think. Sometimes it does not feel like that, the glazing is still a crap shoot and often disappointing, but seeing a bunch of greenware mugs on the table with the handles all done feels great. A few blunders here and there, lost a few, tossed a few, but I feel like the quality has gone up quite a bit. I even got creative with a few of them and experimented with handles and tried lots of different mug shapes. I need to make another 300 handles it seems, before it really clicks, some of these are still pretty amateur. Throwing the forms has gotten way easier and faster, maybe still a tad heavy on the bottom for some of them, but not boat anchors like some of my previous attempts. Thanks in a big way to all of you that have helped me with the bazillion questions and given great feedback, the folks on this forum are awesome! Any and all critiques, criticisms or comments appreciated
  6. Firing 3rd glaze test....

  7. shawnhar

    Home Studio Information

    You need to actively vent the kiln fumes to the outside and also have an adequate intake of fresh air in the room with the kiln.
  8. Interesting... I have gotten a lot better at getting the clay up from the bottom, but I still can't make the tapered shape I want without using the "wooden knife" tool to carve off a little of the of the bottom and put the final shape on it before wiring it off. I have had "some" luck shaping the bottom with a wooden rib while throwing, but more often than not, that introduces a wobble, or I get the clay too thin down there because I can't feel it through the rib. It has made a big difference in my trim time too, not trimming for shape, just to put the foot ring on. I need to make/get one of those right angle trimming tools that grabs the clay as you trim off that bottom bit, half the time I mess up the bottom if I try to do it in 2 moves while the wheel is still spinning as the wooden knife pushes the clay back up against the pot or doesn't grab it right, etc...
  9. Bisquing ma test pots....

  10. shawnhar

    Advice for 1st glaze firing?

    Perfect info man! I am guessing that is what I will get with cone 5 and no hold, based on my previous result, if so I can put in a cone offset and add a hold, hopefully that will get me in the ballpark.
  11. Just about ready to do my first glaze firing in a couple of days and looking for some feedback or just a sanity check. I can't bear the thought of ruining an entire kiln load because I didn't do my due diligence or overlooked something simple. My kiln is a Skutt KM818, it's much smaller than the 1027's at the studio and I know it will fire slightly different. I'm not too worried about that, just want a semi-safe starting point. My glazes are rated cone 5/6 and are the same ones used at the studio, they were just mixed from dry ingredients 2 days ago. The studio fires their kilns to cone 5 with a 10 or 15 minute hold, I forgot which, and I believe they said that puts them up right at cone 6. They do not use vents. I am using a vent, and I am planning to use the pre-programmed cone fire mode, medium speed, to cone 5 with a 10 minute hold. No fire-down, turn the vent off after the hold completes. I have cone 5 and 6 witness cones to spread around the kiln. The only other variable that might have an impact I can think of, is I fired my bisque to cone 06, rather than 04 like the studio does, not sure if that would have a big impact on the glaze firing, but I did read it might make the pieces absorb more glaze when I dip them so I need to be careful about the thickness. I plan to bisque the next batch to 04 and compare (if this 1st glaze firing goes off without a hitch). Am I overthinking it or is this a solid firing plan?
  12. shawnhar

    Advice for 1st glaze firing?

    Thanks Yappy and Stephen, just waiting for my test pieces to dry so I can do another bisque and then I will use those at ^5 with no hold, go from there. I have enough to run 4 test fires and hoping I will find the sweet spot.
  13. I saw a woman on utube that uses one in her throwing water. I wondered if you couldn't just keep a coffee pot full of water and keep putting some in, it appears Liambesaw has tried topping off with boiling water and it still gets cold fast though.
  14. I bet that is exactly true, I suspect no handles would be a tough sell in my area
  15. Thanks Joseph, all of those were 1lb 4 oz. of clay. I trimmed off 3 or 4 oz. from the bottom on most of them at the time of throwing, some much less and then carved foot rings in almost all. I did some with 1lb but I like the thicker ones, keeps my coffee warmer longer, the thinner ones with less clay "feel" like a better made mug...but my coffee gets cold before I can drink it. The final glazed mugs were 4 /2 to 5" tall. Thanks Rex, it would not have occurred to me to make handle-less mugs! You sell many like that?
  16. Skutt KM818 3" Cone fire mode, medium, cone 6 with 10 minute hold Clay: Highwater Buncomb White cone 3-6 Bisqued to cone 06 (except one cone 04 mug) Glazes: pre-mixed local studio glazes rated cone 5/6, mixed about 2 weeks ago. White, Turquiose, Floating Blue Firing time was 8hrs, 38min Kiln was not packed tight, bottom shelf was just about full and top half of the kiln had some empty space, probably could have used a half shelf and put 4/5 more mugs in, but was afraid or ruining a whole load so left it somewhat sparse. Overall I am pretty pleased with the result cionsidering it was my 1st glaze fire ine the "new to me" kiln. Several pieces ran but not too bad, that floating blue is notorious for ruining shelves at the studio. The glazes are much darker, and blended together much more, than I get at the studio. I love they way they blended, and they have way more texture, which I also love, but I do wish they were a bit brighter. Makes sense now that I know the studio fires these glazes to cone 5 with a 15 minute hold, and a great learning experience to see how much of a difference that is from my firing. A couple of small defects here and there but no pinholes or crawling and nothing ran down all over the shelf. As a first firing, I'd call it a smashing success!
  17. Thanks Min, that is brilliant regarding the mass, I feel really dumb now, wasting my mugs on the second firing when I could have just filled the kiln with shelves and furniture with a few test pots and next firing will do just that. Set the TC offset, use furniture and shelves for mass, and use a firing program provided by dhpotter, which was based on yours and Tom's recommendations, to slow the ramp up to the final temp, let it drop, then hold. First thing though is just do the TC offset and do a cone 5 no hold with a couple of test pots and witness cones, then go from there. Making my test pots tonight Thanks you everyone!
  18. Thanks Fred, sorry I wasnt clear. The first firing was cone 6 10min hold, and it overfired with ^6 cone slumped down, the glazes came out dark but they were mostly smooth, some slight blistering I think and some pinholes but not too bad. Second firing with new pieces was cone 5 with 15min hold, witness cones showed ^6 bent over with tip touching shelf, they came out blistered/tons of pinholes, so I refired those again, same cone 5 15min hold , they got worse. Guess I should have tried cone 4. I have to make a bunch of basic pieces for the next test fire in stead of wasting all my mugs on this, sucks losing them.
  19. Thanks Rae, I took the glaze down to the studio and sieved it, nothing wrong with it, no chunks, was told it's my fire, not the glaze. Thanks Liam, I'm sure they would. - So, I am completely lost now. Refiring made all of the pitting/blistering/pinholing worse, WAY worse. The first attempt fired over (cone 6 w/10min hold) and has problems but is a lot smoother, the second batch fired to cone 6 (5 w/15min hold) was a complete failure, every glaze was ruined. I have no idea what to try now, cone 6 with no hold?
  20. I don't have a sieve yet, I bought a paint mixer attachment for my drill and used that. Should you have to sieve glazes you bought as liquid 2 weeks ago? Surely folks don't sieve every time they glaze... Just if you notice it's chunky. I also picked up one of those hand held immersion mixers and I'm hoping the shear action will break up most of the chunks. I tried the "wet foam rub" but the foam I used was too soft and too much glaze was rubbed off, I need to find some denser material. I have some boat carpet left over from a project and will try that.
  21. Thanks to all! dh, I did just that , cone 5/ 15min hold, on the second firing and it was much better, good info on the TC distance, never would have thought of that. Stephen, make sense on the cones, I need to order some 7's so I have a spread, have some 5's and put one in the next firing. The ^6 looks good to me? Drips/even bottoms is a goal and the more stable glazes I am getting better at predicting, sponging the glaze consitantly off the edges is a skill it's self I am still working on. I looked up the recipie for my turq and it is not Val's, this one doesn't move much at all, very stable. I like, pristine, bottoms and I cannot lie, you other potters try to deny... Completely agree and that is the goal. Pres, I think I need to thin the floating blue more, the fail below was a double dip, I knew better too, it took a long time to dry, but I wanted to push one mug and see. Good tips on the dipping, and adding a catch, and your firing details. Johnny, thanks, I figure if run a glaze fire 3 or 4 times a week for a year, I'll be there, untill I change glazes, or get a new kiln, or clay...lol. Gabby, I am going to try that next time, I also read about spraying water on certain parts to thin the glaze. Min, thanks for the info. ^5 with 15 min hold came out much better overall, my Turq failed though, saw it was chunky and should have waited until I could deal with it. Taking it back to the studio tomorrow to have them look at it/seive it. I thought of refiring just the the green and hoping it would smooth out, maybe ^5 with a 20 minute hold or just putting them in with the next glaze batch? If by themselves the kiln would be mostly empty. I have some black mugs with little tiny burst bubbles on the inside I would add to the load hoping they smooth out as well. Color is WAY better and I think the cones are what they are supposed to be, maybe a tad on the high side but I bet lower and the colors would not be as rich, which I like.
  22. Wow tons of great feedback and tips! It will take me a while to respond to everyone but I wanted to say thanks to all of you. oldlayy, when I bought the wheel/kiln they lady gave me everything she had and there was a box of kiln furniture with those and about 50 other pieces of various sizes and shapes. but those are the only ones i've used, I like em' too! Yappy, I didn't care for the way the blue came out either, next firing came out more blue, will post results later but it did better at ^5 with the 15 min hold.
  23. Thank Neil, I am waiting for last nights firing to cool but it showed a peak temp of 2172 at the end of the cone 5, 15 minute hold. Still have about 4 hours before I can get a look at the results.
  24. Funny you mention that as I was just reading about it last night, apparently 2% is ok, but beyond that it gets iffy?
  25. Ha, thanks Babs, I keep meaning to do that, but I really like it when the glaze goes right to the edge, it's a catch 22. I added some water and mixed the heck out of the blue and turquoise, glazed another 20 mugs and just started the cone 5 with 15 minute hold, I hope they come out a ton brighter. Made a couple with thicker blue, I bet they run....
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