Jump to content

fgvanatta

Members
  • Content Count

    12
  • Joined

  • Last visited

  1. I appreciate all the info. As mentioned, the kiln is firing fine according to the cones (my final ramp is 100°/hour, fairly close to the 108° in the cone charts) and the cones on all shelves are bent to 90° after the firing. The real issue is that the controller reports the final temperature as it is firing - 2241°; then, when the firing is over, the same controller reports the highest temperature reached as 2236°. Why is it reporting two different temperatures? Skutt says this is normal. My suspicion is that the temperature reported as the kiln is firing is a direct reading from the thermocouple, while the "highest temperature" value shown after the firing is complete is the controller's attempt to report heat work. In any case, the firings is OK, so the question becomes a simple question of logic. Thank you all again for all the information.
  2. Everything but the tip is enclosed in a ceramic shield. Current TCOS setting is 15 (Kiln firing 15° cooler). I didn't set this; it's the way the kiln came (slightly used). This doesn't seem to make sense, as the kiln is firing properly - according to the pyrometric cones - @ cone 6 and the reported highest temp, 2236°, is reasonable. To further complicate things, bisque firing @ cone 06 also seems to be at the right temperature according to the pyrometric cones, but the reported highest temp is 1805°, considerably lower than the 1828° shown in the Orton cone chart, even with the offset. I'm tempted to go back to Skutt and get some answers. At the same time, my "if it ain't broke, don't fix it" mantra is kicking in. Methinks the best course of action at this point is to leave well enough alone and keep monitoring via the cones until an actual problem occurs.
  3. The kiln uses a type K thermocouple; it's not zone controlled. I got a reply from Skutt; they just said the discrepancy is "normal" - no explanation why. Obviously not a situation to worry about, but I prefer to have a better handle on the way things work. Frank
  4. I'm sure the glaze chemistry changes - for whatever reason - as the glaze goes from ambient temperature to 2200+° but it would be nice to know why so one could figure out in advance which glazes will react adversely to down firing. Since you mention marked changes in Coyote Sunset Pink methinks I better be careful with Archie's Base, which I use a lot. Hopefully someone here can provide more insight into the chemical goings on of these glazes under fire.
  5. I use cones on every shelf for every firing and they have all been @ 90°, so I'm not really concerned about the amount of temperature difference - I was just concerned about the reason for the inaccuracy. (If the controller has a "slight" problem in one area, what might be lurking elsewhere in its innards?)
  6. I have a fairly new Skutt KM822 (about 20 firings). As I was waiting for the cycle to complete yesterday, I noticed that the temperature went to 2241° before the kiln shut off. When the firing was complete I used "Review" to check the "Highest Temperature Reached" and it reported 2236°. I don't know if this is normal for this controller or something is wrong or it can be accounted for as heat work instead of temperature. I emailed Skutt about this yesterday morning, but haven't received any reply yet. Anyone else out there have any ideas about this?
  7. I'm not sure why some cone 6 glazes change color rather drastically when refired to a lower temperature, but maybe someone can explain. Specifically, Coyote Ice Blue glaze fired to cone 6 turned out the usual beautiful multi-hued blue, brownish at the breaks. Then I decided to put some low fire clear glaze on the bottom and refired the piece at cone 06. The result was an awful, mottled green and brown camouflage-like color. Yeechhh!! So I refired back up to cone 6 again hoping to recover the blues. The piece now looks much better - the greens are gone - but the subtler blues are also gone and there is more and deeper brown. As it happens, I did the same thing to several other pieces with different commercial glazes on them. All of them suffered significant color degradation after the 06 low fire, and recovered only a portion of their original color in the second cone 6 fire. With one exception: a bowl with a combination of Amaco Textured Turquoise and Amaco Iron Lustre looked pretty bad after the low fire but almost completely recovered its original color after being refired to cone 6. I thought it was safe to refire pieces at a lower temperature, but I am obviously mistaken. Any insights on this phenomenon would be appreciated.
  8. Try using Laguna Clay's ^6 Speckled Buff. It looks pretty much like this when fired to maturity. Specks seem to be caused by the inclusion of metallic oxides, which play havoc with some glazes. I highly recommend test firing any glazes to be used with this clay.
  9. Brushes are easily cleaned of wax resist with vinegar. Follow with a little baby shampoo to make the bristles soft.
  10. Good point; we use so many washes around here that I didn't even think about it. I also don't know how concentrated the mix was. You've probably hit the nail on the head since the glaze didn't drip at all - just fell off. Thanks for the insight; the older I get the more I seem to forget. Frank
  11. A wash of "Intensive Red Cerdec Stain" was applied to bisqued B-Mix Cone 10 Clay (bisque fired @ cone 06) then dipped in Laguna Flambe Blue glaze and fired to Cone 10. The stain and Flambe combination produced a dark blue glaze that crawled off about 75% of the bowl's surface and ran more than any glaze I have ever seen, causing two "splashes" of glaze on the shelf that dripped off of the bowl without running down to the foot. I have fired this Flambe glaze both alone and in combination with several other glazes without ever having it run excessively; applied by itself it runs very little. I have no experience with the Cerdec-Degussa stain. Has anyone run into a similar problem/phenomenon with this stain? It is an encapsulated stain and is not supposed to flux at high temperatures (so they say).
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.