Peep holes, cracking lids & opening the kiln ~ stoneware

[Meredith Kathleen]

Hello,

I am firing my L&L electric kiln with mostly white stoneware (as well as black vulcan) and had some questions about the post firing cool down. 
I can get a little impatient so need some guidelines so it doesn't get the better of me.

I have a top peep hole and two side ones.
I generally leave the top one open during the entire firing...the side ones are sometimes in, sometimes not in...I haven't been great at keeping track and observing any effects (erps).
Sometimes I pull out the peep holes at the side during the cooling down, maybe around 400F, today I did it at over 700F and heard some crackling...still too hot to open so no idea what happened yet.
What temp do you open peep holes?
What temp do you crack the lid?
What temp to you open the lid?

This is for both bisque & glaze fire.

Many thanks!

[Roberta12]

I never fire my L&L without peeps.  They are always in.  But I have a downdraft vent.  Do you??  I don't open the kiln until 200 degrees F.  I will confess that I have been known to peek before that, but I don't fully open until 200 or lower.    I do the same for both bisque and glaze.  I had read that there is still some glaze development going on until 300-400 degrees F.  However, there are many more knowledgeable than me on that topic.

Roberta

[dhPotter]

When to Open the Kiln

1. When the kiln temperature falls to 600°F, open all the peep holes.

2. When the temperature reaches 450°F prop the lid 1 inch.

3. When the temperature reaches 350°F, the lid/door can be opened 3 or 4 inches.

4. When the temperature reaches 250°F you may completely open the kiln allowing it to finish cooling prior to unloading.

5. When the temperature hovers around 200°F the kiln can be unloaded.

[Roberta12]

15 hours ago, dhPotter said:

When to Open the Kiln

1. When the kiln temperature falls to 600°F, open all the peep holes.

2. When the temperature reaches 450°F prop the lid 1 inch.

3. When the temperature reaches 350°F, the lid/door can be opened 3 or 4 inches.

4. When the temperature reaches 250°F you may completely open the kiln allowing it to finish cooling prior to unloading.

5. When the temperature hovers around 200°F the kiln can be unloaded.

@dhPotter I was wondering why you take out the peeps?  I know some potters do and some don't but what is the science behind taking the peeps out and cracking the lid?  

[dhPotter]

@Roberta12 Not sure about the science.

It is my guess to allow the heat to escape faster than letting the kiln cool on its own without help cooling. I leave the downdraft vent running until the peeps are removed. Sometimes I do as you do and let the kiln cool on its own down to 200*F leaving the downdraft vent on. 

[Roberta12]

1 hour ago, dhPotter said:

@Roberta12 Not sure about the science.

It is my guess to allow the heat to escape faster than letting the kiln cool on its own without help cooling. I leave the downdraft vent running until the peeps are removed. Sometimes I do as you do and let the kiln cool on its own down to 200*F leaving the downdraft vent on. 

Just wondering.  Like most things involving pottery, everyone has their own methods.    

r.

[neilestrick]

Cooling with all the peeps open won't hurt the work. From an energy efficiency standpoint, keep all but one closed if you're not using a downdraft vent or you're just letting out heat. I would plug the top peep and keep the upper side peep open. Keep all of closed if you are using a downdraft vent. I open my kilns fully open at 300F unless I have some large pieces in there. Nothing bad ever happens. If the glaze is going to craze it's going to craze, and another 50-100 degrees of slower cooling isn't going to matter.

On 8/31/2021 at 2:10 PM, Meredith Kathleen said:

today I did it at over 700F and heard some crackling

The kiln will make crackling noises as it cools. If the pots are making noise it's more of a ping than a crackle.

[Meredith Kathleen]

On 8/31/2021 at 8:34 PM, Roberta12 said:

I never fire my L&L without peeps.  They are always in.  But I have a downdraft vent.  Do you??  I don't open the kiln until 200 degrees F.  I will confess that I have been known to peek before that, but I don't fully open until 200 or lower.    I do the same for both bisque and glaze.  I had read that there is still some glaze development going on until 300-400 degrees F.  However, there are many more knowledgeable than me on that topic.

Roberta

Thanks Roberta...ummm, I am not certain if I have a downdraft vent?  where/what is that?

 

[Meredith Kathleen]

On 8/31/2021 at 8:34 PM, Roberta12 said:

I never fire my L&L without peeps.  They are always in.  But I have a downdraft vent.  Do you??  I don't open the kiln until 200 degrees F.  I will confess that I have been known to peek before that, but I don't fully open until 200 or lower.    I do the same for both bisque and glaze.  I had read that there is still some glaze development going on until 300-400 degrees F.  However, there are many more knowledgeable than me on that topic.

Roberta

I leave the top hole open and peeps in, in general...

[Callie Beller Diesel]

3 hours ago, Meredith Kathleen said:

I am not certain if I have a downdraft vent? 

You would know if you had one. It’s a separate fan/ductwork attachment that draws fumes out of an enclosed area and helps the kiln fire more evenly. A downdraft vent is mounted on the bottom of the kiln, and an overhead vent is mounted above a kiln. Some manufacturers will sell both as a kit, but mostly they’re sold as separate items.

[Meredith Kathleen]

14 hours ago, Callie Beller Diesel said:

You would know if you had one. It’s a separate fan/ductwork attachment that draws fumes out of an enclosed area and helps the kiln fire more evenly. A downdraft vent is mounted on the bottom of the kiln, and an overhead vent is mounted above a kiln. Some manufacturers will sell both as a kit, but mostly they’re sold as separate items.

nope, i dont have one!