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My very first firing in 18 years of clay


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#1 Jime

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Posted 25 March 2013 - 06:59 AM

Hi all

I just did my very first firing, after 18 years of clay.Exciting and scary!

I could use your input, I wonder if I’m worrying fornothing, or if something is off.

I have a cress fx 23 kiln, I bought it from someone who hadbought it new and never fired it, and had the breaking-in firing done by atechnician who said it was in great shape.

For the firing I used the manual setting, controlling thechanges myself. This was a bisque firingto 04 with a witness cone for the top peephole. I made a rookie mistake andthough I put a cone in to the sitter, I failed to lift the lever when I put thebar in! I tried to fix it, but I ended up breaking the kiln sitter cone.Instead of unloading the kiln to put in a new cone, I chose to go ahead anddepend on the witness cone.

I had it on low for 3 hours, moving the dial up by 0.5 or 1at every hour. Then I had it on medium power for 2 hours, moving from 2 to 4.5.Then I moved it to 7, and waited 1.5 hours and moved to 8.5. Another hour withno change and I moved it up to 10. after 1.5 hours at 10, I finally saw thecone bend, so I turned the kiln off.

So the total firing was 3h on Low (1-4) 3h on Med (4-7) and4h on High (7-10)

Does that seem too slow to you? I had expected the Highphase to be a bit faster.



Are there any things that you notice me doing horriblywrong?

After setting everything up I finally read that I wassupposed to put kiln wash on the kiln sitter supports! Since I broke the sittercone, the point was moot, but now I’m wondering if it was bad to have left thebroken pieces in the kiln… are they at the bottom of the kiln in a gooey mess?!We’ll have to see.

I’m planning on waiting 12 hours to open the kiln, does thatseem about right to you?

I’m also thinking of trusting the Firemate speed control next time, instead ofmaking the temperature changes manually…

so, it’s been an exciting night over here, a real trial by fire ( J)
A new stage in life, where I fire for myself!

Thanks for all the kindness and support, you’ve all beeninvaluable.

#2 Marcia Selsor

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Posted 25 March 2013 - 07:14 AM

How are you determining the achieved temperature? You say there is no cone in the sitter. Do you have witness cones or a pyrometer?
If you go hotter than 04 , yes you will have a gooey mess on the floor of the kiln from that broken cone.

As for when to open, put twisted newspaper in the peep holes. If it burns it is too hot (over 451 F)
Wait an hour or 2 after it is not burning. Cooling is not dependent on a precise time, but depends on how densely pack the kiln may be.

Marcia.

#3 Chris Campbell

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Posted 25 March 2013 - 10:03 AM

Now you know why we love our computer controlled kilns!! : > )

They fire right, without stress or hassle.
Until you get fancy on your firings, your computer will do a good job for you. You will still need to use witness cones to make sure of your results, but my recommend is to let the computer do the work.

Chris Campbell
Contemporary Fine Colored Porcelain
http://www.ccpottery.com/

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TRY ...   FAIL ...  LEARN ...  REPEAT


#4 Jime

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Posted 25 March 2013 - 10:24 AM

thanks Chris and Marcia!
yes, I counted on a witness cone, it just took forever to bend! I hadn't expected to need 4 hours on high!
No, my kiln doesn't have a computer, it has a special dial that can control the speed of the firing. in fact, I hadn't noticed it and all of a sudden the temperature had changed by itself! I eventually found it on the side of the panel (kind of hard to see the way the kiln is set up).
thanks for the help!

#5 Jime

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Posted 25 March 2013 - 09:45 PM

I just unloaded the kiln, and it was absolutely spectacular. The cone was exactly the right shape and nothing cracked!!
after all these years of being terrified, this is seeming very manageable!
newbie success!!

#6 Marcia Selsor

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Posted 25 March 2013 - 10:20 PM

Congratulations.
now on to glazing.
Marcia




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