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When I am firing my electric kiln, I start with the lid propped open about 2 inches and the top peephole out. Then at around 1000 degrees F I shut the lid. The top peephole is open the whole time. I understand that the lid needs to be propped to allow moisture and gasses to escape in the early stages of firing. My questions are:

1) is 1000F an appropriate temp to close the lid?

2) Is it necessary to prop the lid on a ^6 glaze firing as well as the bisque, or only during the bisque (^06)

 

I have been firing this way for a couple years and the pots always come out well. However the lid has badly cracked on both the inside and outside, necessitating repair with kiln cement. I have a large electric Skutt Kiln (I think it's the 1227). Even with my repair, it is all fractured and occasionally falls onto the pots below. The metal handle is also badly rusted and corroded, an issue I didn't notice when I bought this kiln used a couple years ago. 

 

I notice when I close the lid on an 1000F kiln it makes a soft settling crackling noise. I am curious if the cracking lid is from thermal shock when it goes from hot room temp to 1000F. Because of this, i wonder if it's better not to close it so late (and hot) in the firing. Perhaps it's just time for an envirovent. 

 

Is it normal for a lid to start to deteriorate like this? The newer versions of my kiln are made with the hydraulic lid lifter, which I assume lifts it more evenly, without the torque from supporting it on just one part. Please let me know if anyone else has had this cracking lid issue.

-Dana

 

 

 

 

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Post some pics.

 

It's not necessary to prop the lid. Just leave the top peep hole open and you'll be fine. Propping the lid is bad for the lid, and bad for the top rim of the kiln body, and totally unnecessary on kilns with decent switches. The only time propping is necessary is on really old kilns that just have on-off switches (light switches), where propping the lid slows down the firing so things don't blow up. But with low-med-hi or infinite switches it's easy enough to do a slow start, and the top peep will vent out the moisture and fumes just fine.

 

You should be using a vent if the kiln is anywhere near a living space.

 

When you say cracking, do you mean the surface of the lid is cracking and flaking off, or the bricks are cracking apart? Surface cracking and flaking happens on old kilns. The best you can do is scrape off any loose stuff and go over it with some thinned out kiln cement. But even then it'll just keep happening. You ca put a kiln shelf at the top of your load to protect the pots. At some point the lid needs to be replaced, or flipped over if the other side is in better condition, or swapped out with the floor if it's better.

 

The modern hinges are nice, and much easier to lift the lid on a kiln that size. They're not hydraulic, but spring loaded. Retrofitting is kind of a pain and expensive. A cheaper, simpler solution is to rig up a pulley with a counterweight above the kiln.

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Yeah, Neil been meaning to rig up a pulley system for my L & L for years. I have an old econo with the four sections for when I fire larger. Problem was always moving the section with the lid and hinge, and finding the right storage and such to take care of the leftover, but then that meant always moving two sections to put the lidded section on. Long of the short, last time I ordered a lid(extra thick), I put on the old lids handle on opposite side. Easily lift the lid and store on side next to kiln, also easy to put on that fourth section. However, a pulley system would be really nice the older I get.   :huh:

 

 

best,

Pres

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neil has given you very good advice.  so do what he says.  

 

you may have been causing  the breakage by propping the lid so high.  i have propped my lid since 1972 but only half an inch or less using a tiny bit of broken brick or a 1/2 inch post on the metal edge that is folded under the lid and over the top of the wall.  never on just the bricks.  2 inches is a huge amount of stress for that lid to withstand.   

 

my firing pattern is very different from the average potter, i tightly pack and single fire from greenware to glaze.

 

(it is not the temperature that determines when to remove the prop and close the lid, but the moisture coming out of the opening that tells me when.  once i cannot see vapor on a mirror held at the edge of the lid, i can safely close it.  check previous posts for accurate temperature when this is expected.)   

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Thank you all for your responses! I only wish I had joined here earlier and known all along that I didn't need to be propping because it was a lot of trouble. ( I usually fire overnight, so I'd have to wake up to close it). I like the idea of switching my broken lid with my floor piece.

 

what is the best way to attach a new handle to the kiln brick with the metal band? 

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I reused the screws that were holding the handle on the lid when I switched them.  If they are too rusty to use go to a hardware store and buy some replacements, don't forget to take the old one with you for comparison.   Denice

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I reused the screws that were holding the handle on the lid when I switched them.  If they are too rusty to use go to a hardware store and buy some replacements, don't forget to take the old one with you for comparison.   Denice

If You replace rusty screws, do so with stainless steel. They're a little more expensive, but they're stronger and won't rust.

JK

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JohnnyK is right on there, the stainless screws are really the only way to go. I attached my second handle to the lid with these, and checked the specs on the lid handle that came with it-stainless.

 

best,

Pres

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are you planning to use the broken lid as a new bottom and using the undamaged bottom as a lid?  can you send photos so neil can judge its condition to do this?

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i am thinking about the damaged top.  if it is in bad condition, it seems counterproductive to put all the weight of the loaded kiln on it.

 

If it's just flaking it won't be a problem at all. Better at the bottom than at the top. If the lid is actually cracked, then you can still use it one the floor, but it would be wise to put a piece of sheet metal under it to give it more support. The shelf posts will rest right about where the kiln stand supports the floor, so as long as the outer band is tight the sheet metal will provide enough support for it. It's not ideal, but I've seen cracked floors go for years like that.

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