jrgpots
-
Posts
958 -
Joined
-
Last visited
Content Type
Profiles
Forums
Gallery
Posts posted by jrgpots
-
-
I have been thinking of adjusting Aardvark Coleman white cone 10 to cone 7. I'm having problems finding good reference material about quantities and types of fluxes.
Jed
-
Mine is the pink powder. It is really hard to know exactly what it is! I will calcine about 500 GM of the stuff and see what happens. I will compare it to Zn oxide in a side by side recipe with the calamine. Maybe opacity a celadon and see it there is a color change because of the Fe.
Jed
-
-
Fe2O4Zn is what pubchem quotes it to be. Sorry I dropped the subscript on the Oxygen. In my research I also found Zinc Carbonate as well as hemimorphite. The clay was mined in India. It does not give chemical analysis. This is all I have.
I thought I would heat it up dry to drive off any CO2, leaving the Fe2O2Zn.
-
I bought about 5 lbs of calamine clay powder to use in cosmetics creams. It didn't work out too well. So now I have it for other uses. Calamine is Fe2OZn. Has anyone used it in glazes? If so, please share.
Jed
-
In my excitement, I pushed it too fast. Next time I will have a higher bag wall and slow down the firing in the last few cones. I think I just need to get acquainted the my new girl. Thanks everyone for the insights.
Jed
-
10 minutes ago, neilestrick said:
Raise the bag wall a few inches.
The bag walls were 9" plus the thickness of one shelf. How high should I take them? I could rais the bag wall to the third shelf ( 13.5").
-
Explain "kiln losses from the shell." If you are referring to heat loss, The sidewalls and front walls are 9" IFB. The arch is 9" also. The floor has a 4" hard brick foundation, then 4.5" IFB, then topped with 2.5" Hard brick. I could throw wool on top of the arch. But it really di not get too hot. The greatest loss was from the front door.
Jed
-
The firing chart is uploaded. Temp(Celsius) vs Time (Hours). the initial few hours were with venturi burners. Power burners were started at about 300 degrees. The damper was at 1.5 " open. (it burns well at that setting). Short time of reduction at 900 degree ( 20 minutes or so). The kiln's rate of climb was slowing in the last hour or so, but I think I should have slowed down a bit more. The last 20 minutes , the kiln was again placed in reduction.
The lowest kiln shelf was 4.5 inches off the floor. Fire brick slits lined the outer shelves edge creating bag walls just on the inside edge of the flame troughs. 2 burners at the back on either side facing forward. I did not put deflecting bricks in the flame trough. Flame troughs were 4 " wide. Hard fire brick splits on their sides were used to support the shelves and make the bag on the inside edge of the fire troughs. The second shelf was 8 " above the first and the third shelf 8" above that. I did not bag wall the front of the first shelf. I will do that next time.
Jed
-
I just finished my first firing of my new down draft gas kiln. The bottom fired one cone hotter than the top. So, how do I even the thing out? Normally, I thought the top was hotter than the bottom. If the bottom is hotter than the top, would I open the damper up a bit more to even out the temp?
Also I got bubbles on one of my glazes. Could this be from a too rapid of ramp or did I need to let the kiln run for longer at the end? The glaze did not bubble with electric kiln.
Jed
-
The arched iron work is from Costco. The roof line matches my house roof line. The side walls will be non combustible. The studs are steel. The surface will be stucco on cement board. Lots to do.
-
This is my finished kiln. The interior is 32 x 32 with a height of 34. Nine inch wall of IFB . I am only part way through framing the shed around the kiln. It is a down draft with two power burners. The bisque firing took 8 hrs and my very first cone 6 firing took 10 hours. I took it slow with two venturi burners for the first 3 hours before firing up the two power burners. I was a bit hesitant to go fast from the onset, especially when I am so new to all of this. The kiln is at about 250 degrees Celsius right now.
Things I've learned so far:
1. A small adjustment in the damper make a huge difference.
2. The kiln has it own rate of heating up. Resist the temptation to give it more gas. Instead, be patient.
3. I need better WiFi coverage out by the kiln.
I know this is not earth shattering, but I made it with my own 2 hands. So I am tooting my own horn. I am excited
Jed
How to lower a cone 10 clay body to cone 7?
in Clay and Glaze Chemistry
Posted
Thanks. I now have starting point