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Firing Without A Vent Kit - 2 Quick Peephole Questions


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#1 grype

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Posted 10 July 2014 - 08:53 PM

I have a 2 section easy fire 18 L&L. I don't have a vent and I fire with the top peephole out and I plug that hole at around 2/3 max temperature. I am having an issue with some minor pin-holing and I think it is either from my bisque not being allowed to burn off all the gasses because I am plugging too early, or my glaze firing is also getting plugged before the glazes can finish releasing the gasses. So I plan on leaving my top peephole out the entire time for the next bisque and glaze firing. I bisque to 05 and glaze to 6.

 

1. I emailed L&L and they said that a kiln of this size wouldn't have any problems venting with just the top peephole out, however they said I might need to plug the hole to reach temperature. Does anyone have experience leaving the top peephole out the entire time? The kiln doesn't seem to have any problem getting to 2/3's the temp with the peephole out at all. My first firing I plugged it at 1500, then the 2nd at 1900, and they both had the same exact time on the minute for getting to Cone 6. I was pretty impressed.

 

2. After the kiln shuts off, should I set an alarm when it reaches temp so that I can plug the peephole so that it cools in a normal time, or should I just leave the peephole out? I figured it would cool too fast with the peephole out and cause cracking or shivering? If I plug it right after it shuts off am I trapping gasses and causing pin-holing during the cooling?

 

I hope I explained this well enough. I am in my 3rd glaze firing coming up and I want to fix this minor pin-holing for good!



#2 Biglou13

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Posted 10 July 2014 - 09:23 PM

We leave lid cracked open until 1000f. And still leave top peep hole out. Throughout whole process. I recently started putting some furniture when i can inside of open peep.

Neil e is a l&l rep. I'm sure he'd be the go to for this one.
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#3 neilestrick

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Posted 10 July 2014 - 09:28 PM

Do not crack the lid. With a zone control digital kiln like the L&L it can cause issues with the controller since the top will be fighting to stay as hot as the other sections. You should have no problem leaving the top peep open through the entire firing. Many of my school customers that only have overhead hoods, not downdraft vents, do it that way. It will reach temperature just fine. There's no reason to plug it at the end of the firing, either, unless you find that it's cooling too quickly with it open. It's unlikely to cause shivering or cracking, but you may find your glazes look better with a slower cooling.


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#4 Benzine

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Posted 10 July 2014 - 09:49 PM

I would be one of such schools Neil.  Just an overhead vent, and I  keep the top peep out, through the initial firing stages of the bisque.


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#5 Biglou13

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Posted 11 July 2014 - 03:36 AM

I'm following skutt manual directions.
The studio does have overhead vent, although the room still does get hot.

Is propping kiln overkill? I this old outdated information?

My understanding propping open until 1000f. Vents kiln better gases/ steam/ water, and also helps increase longevity of kiln bricks and elements

We are using skutt 1027, 1227
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#6 grype

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Posted 11 July 2014 - 08:03 AM

Thanks for the information. I will start leaving it out the entire time and I think I will plug it at the end. I am not in a super hurry to open the kiln the glazes looking better is way more important to me than opening it 5-6 hours quicker. Thanks for the help everyone. I will post if this helps with my pin-holing issue. I hope it does.



#7 neilestrick

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Posted 11 July 2014 - 09:31 AM

I'm following skutt manual directions.
The studio does have overhead vent, although the room still does get hot.

Is propping kiln overkill? I this old outdated information?

My understanding propping open until 1000f. Vents kiln better gases/ steam/ water, and also helps increase longevity of kiln bricks and elements

We are using skutt 1027, 1227

 

It is overkill in most situations. And even with a single zone digital control it can sometimes cause the controller to freak out. One of the Skutt techs once told me about a specific situation where they couldn't figure out why the controller kept throwing up an error code, and eventually they figured out that the customer was propping the lid.


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L&L Distributor
Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

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#8 grype

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Posted 12 July 2014 - 06:22 PM

Well glaze firing is a going!

 

Bisque to 04 didn't seem to take any longer than with the top hole plugged. I didn't check the exact time but it was around 5-10 minutes of the previous fire where I plugged it at 2/3 temp.

 

Fast Bisque to 04 and Slow Glaze to 6 (5 minute hold). 

 

I will post details if the pin-holing went away with both the bisque and glaze firing done fully with the top peephole out. I think I am going to plug the glaze firing once it completes to ensure the best possible glaze results.

 

Hopefully this does the trick. 112 brown spec seems to have so much more trouble with pin-holing compared to the pieces I made with b-mix(grogless). Results tomorrow afternoon/evening.



#9 grype

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Posted 13 July 2014 - 03:09 PM

B-mix pieces have 0 pinholes, the 112 brown spec is still pinholing. I think it has to do with the manganese specs, as a lot of the pinholing is directly inside of a speckle. I think I am going to change to a different clay. I really like the way some of my glazes look with the 112 but I am tired of the pinholing. Either my glazes are not matching my clay or I just can't figure out how to properly fix the pinholing problem. Off to Clay and Glazes forum I go. Thanks for the help with the kiln question.

 

For the future people who might have a similar problem I am linking the thread I created in the clay and glaze section here: 

 

http://community.cer...nions-on-clays/



#10 Bobg

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Posted 18 July 2014 - 03:30 PM

Grype,

 

What's the glaze you are using inside the bowl in this picture?

 

post-63346-0-62412300-1405285338_thumb.j

 

Bob



#11 grype

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Posted 18 July 2014 - 07:37 PM

That is Amaco's Celebration Glaze. It is called Clementine. http://www.amaco.com...-lead-free.html

 

I love the color. It looks so much better on my bmix bowls because the glaze isn't pinholed. I am hoping I can get it to look that good on 112. I must note the speckles in picture are not from the glaze but from the clay body: Standards 112 tan spec. 

 

I have to warn you the glaze is expensive. Its like 23$ for a pint. However I am making my wife bowls for our kitchen with it, so its a deal!



#12 clay lover

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Posted 18 July 2014 - 07:51 PM

Have you thought about Highwater's Speckled Brownstone?  A high production friend of mine uses it and has no issues.



#13 grype

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Posted 18 July 2014 - 08:21 PM

Have you thought about Highwater's Speckled Brownstone?  A high production friend of mine uses it and has no issues.

 

I just bought 25 lbs of highwater's spec brownstone to try out, it's literally sitting there waiting to be thrown tomorrow = ).

 

I bought 25 lbs of it, little loafters and red rock. Gonna try all 3. The Speckled Brownstone feels way softer than standard 112 so I am hoping it will be much more enjoyable to throw.






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