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Motor

Advancer shelves and cooling in Electric

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I just bit the bullet and bought some Advancer shelves. I fire a 7ct L &L in an outside shed. Its about 30 outside and I'm concerned about when I can open the kiln. I am in the Christmas crowd when it comes to opening. I try to fire early in the morning so it will fire all day when I'm around and then cool all night & I have no choice but to go to bed.  Anyway Advancers are subject to cracking with uneven heating or cooling, but ALL of the references to this come from folks use large gas kilns, you know with dampers and such. Anyone here use Advancers in the electric and how do  you handle cooling?

Many Thanks 

 

 

Edited by Motor
grammer

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Advancers can handle extreme (400-500* per hour)rapid temp change as long as its even across the shelf. That said, if your opening your kiln at 500, and still have a lot of pots holding heat which isnt allowing the shelf to even the temp out you may crack the shelf.

I crack at 350-500*, and open when Im below 300. If you cant wait that long, then you may be buying replacement shelves. Advancers are wonderful, and you will love using them, but now you need to not be impatient and wait till the kiln cools to safe level for your shelves. What's more valuable; 2-3-4 hours of waiting or your $300 kiln shelf?

I should add that if you have a whole shelf (not a half) that it may be more susceptible to thermal shock than a half. Likewise, if there are strong, cold drafts blowing into your open kiln, you may want to be a bit more cautious.

I fire in a gas kiln with my advancers, but the process is the same for both gas/electric kilns when it comes to cooling/heating the shelves. My gas kiln is a car kiln, so when I open my kiln, I drop in temp quite rapidly and from all sides. With a electric top loader, since heat rises, the heat from below may keep the temp more even across the shelf, than in my case where it cools from all sides more rapidly.

Edited by hitchmss

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54 minutes ago, Motor said:

ometimes I do like to crack at about 300....so your info was very helpful.

At that temp you should have no issues unless there is a stiff breeze, or its very cold (outside kiln, middle of winter kind of deal. Essentially treat the shelves like you would your pots. The shelves are in an essence, kind of like porcelain; very tight grained, hard, non porous, etc; thermal shock below quartz inversion temp can ruin the shelves; once above 1064 you can crank.

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I have a potter friend who uses them in electric-they are the 1/2 shelves not fulls. He opens just below 300 with no issues.

These shelve make so much sense for production work. My friend who uses them is hobbyist

Edited by Mark C.

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5 hours ago, Mark C. said:

I have a potter friend who uses them in electric-they are trhe 1/2 shelves not fulls. He opens just below 300 with no issues.

Mark,  

You are the forum's expert on kiln shelves, so I ask:

Is setting a hot (300 F) kiln shelf on a cold floor recommended as good practice?  
I know from experience that taking a hot pot from a Raku reduction chamber and setting the hot pot on cold concrete is asking the pot to quickly acquire additional cracks while setting the pot on a warm fire brick or a block of wood avoids additional cracking. 
  
While I accept that opening and unloading a hot kiln can be successful if done with care, 
care implies having a reliable cooling technique and the equipment that does not damage either the kiln, the ware, the surroundings, or the excited potter unloading the kiln.  

LT
 

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The fellow I spoke about only cracks the lid at 300 degrees-he does not unload it until its cool enought without gloves

Your question really is determined by what type of shelve material is the shelve`

Nils Lou taught me years ago that the kiln furniture really is the decideing factors on up and down temps

I have unloaded with long gloves mullite /cordalight shelves with no damage but do not recomend it (Best shelves for raku  kilns-as they can take abuse) 

As you know these have long crystal matrix in their makeup and are very stron and can take thermo shoc k well

Silicon carbide shelves (the dark grey to black) ones are tighter and can crack more than say mullites with thermo shock resistance .

My English dry pressed high alumina shelves are supewr shock resentant (used them in the 80-90s now in my salt kiln. I had once even put a 2x2 box fan blowing warm summer air to cool my car kiln once before I THOIGHT TWICE ABOUT RUSHING.I suggest not doing this.

Since switching to all advancers I do not force cool at all-just not worth it

As you know fiber kilns cool faster than soft bricks or any mass of bricks. I tend to let that happen naturally-when I was younger and know as (quick cooler) you learn what can work and what cannot.

By the way I'm no expert and as I get older I know less-my only kudos is experience over the long haul 

These days I like a two day cool down-no rush as I'm no longer a procrastinator . Its a better way to life and work

The school of hard nocks is the best learning ground.My art degree was only a starting point in the learning curve that is still going on.

I'm sure placing a hot advancer on a cold concrete slab would crack it.

I knew a fellow who kept his advancers near a swimming pool in so-cal and hosed them by mistake-turns out he found out what happens when they are wet and fired to fast-a zillion pieces and a colasped load. I store all shelves on wood surfaces off concrete directly which can always have dampness to it as its a material that hold water.

Hope that answered the question ?

Edited by Mark C.

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On 2/25/2019 at 6:27 AM, Motor said:

"Since switching to all advancers I do not force cool at all-just not worth it"  

 

This is now me.   Better for the pots and kiln too.....  :)

 

 

Yes better way to go for everything

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