neilestrick

Im so excited for the kiln that i didn’t even check mains fuse before posting this question 
found one fuse blowin, I’ll replace and i hope its will work this time
 

Hi and welcome! I wish it was under better circumstances.
The pictures are worth a thousand words, and thank you so much for including those!
The fact that the piece is broken so cleanly, and in 2 near-perfect vertical lines all the way through means that this wasn’t specifically your clay, or anything you did during building the piece. It’s a nice dense clay  that probably stuck to the kiln shelf due to the mass and size of the piece, and cracked during cooling. For the next pieces, I’d fire them on some sand/alumina so that the piece has the equivalent of little refractory ball bearings to shift around on. You could also use a waster slab that will shrink at the same rate as the piece, but take the brunt of the force and absorb the crack instead.
If the clay survived the bisque just fine, another possibility is to not fire the piece to full clay maturity. Porosity in the end piece is less of a concern for you than it would be for someone throwing functional ware.

Unless you make it considerably thicker, porcelain is going to warp with a form like that. 

Unless you make it considerably thicker, porcelain is going to warp with a form like that. 

@Bill Kielb @neilestrick
Thank you so much!!  
Bill I’m so impressed and grateful for the time and energy you took to help me out! I have been trying to fix this since last year when I received the kiln but nobody had a clue …and in just one day you fixed it!!!  It took a long time and effort for me to get a kiln and I was devastated  because I couldn’t use it.  I can’t express how happy and relieved I feel!! God bless you!! After all this time,  I am about to finish my first glaze firing with the temporary set up, the kiln is cooling now and everything is going great! 

I will follow the advice and update with pictures and results so more people like me can find this post in the future and fix similar issues easily. 
This is a great community and you guys are amazing, thank you so much! 

Computer fans work great for this application. There's already a grill in place on the box, so measure that and get a fan that fits. This is a small enough box that the output of the fan won't matter. Amazon carries a bunch for very low prices.

Is there a fan on the outside of the case that we can't see in the photos? Definitely need a fan to keep the SSR cool.

Not everyone wants to or is able to throw dinner plates on the wheel. I slab build my plates, and it is much faster than throwing and I don't have problems with humping in the middle.
@chris123 I think the issue is either with glaze tension as mentioned above, or it could be from uneven heating/cooling between the edges and the center or the top and bottom.
1. Does it happen with all of your glazes or just one?
2. What size kiln do you have, and what firing schedule are you using?

Not everyone wants to or is able to throw dinner plates on the wheel. I slab build my plates, and it is much faster than throwing and I don't have problems with humping in the middle.
@chris123 I think the issue is either with glaze tension as mentioned above, or it could be from uneven heating/cooling between the edges and the center or the top and bottom.
1. Does it happen with all of your glazes or just one?
2. What size kiln do you have, and what firing schedule are you using?

Not everyone wants to or is able to throw dinner plates on the wheel. I slab build my plates, and it is much faster than throwing and I don't have problems with humping in the middle.
@chris123 I think the issue is either with glaze tension as mentioned above, or it could be from uneven heating/cooling between the edges and the center or the top and bottom.
1. Does it happen with all of your glazes or just one?
2. What size kiln do you have, and what firing schedule are you using?

I'm afraid I kind of agree with BlueBird. If it has half dollar size holes in it due to corrosion, the rest of it is probably not structurally sound.
The non-pugmill option is to simply not wedge and not recycle. Most clay bodies are good to go for throwing right out of the bag.
I switched to slab building about a year ago after 30 years of throwing, due to bad arthritis in my hands. Gotta say I don't really miss throwing. I'm happy to still be working with clay, and the challenges and possibilities of working with new techniques have me more excited about ceramics than I have been in a long time.

There are other cost savings with firing to lower temps besides just the cost of electricity, big time if you're firing to cone 10 in the electric kiln.
- Extended element life. Firing just 04 will give you 2-3x the element life versus glazing at 5/6, double that vs cone 10.
- Longer kiln life
- Longer kiln furniture life
- Less energy removing excess heat from the studio (if you're running AC or fans)
Plus you can increase output with shorter firing schedules, and it's better for the planet.

So the metal rod is the stem? First you'll need to decide what size rod you're going to use. Then when you make the flower, make a short hollow stem at the bottom of the flower that the rod will slide into. Make it big enough to allow for shrinkage of the clay. Make the stem a couple inches deep, and thick enough to support the weight of the flower. Then after firing you can glue the rod into the pocket using marine epoxy.

I have seen freishly glazed pieces blow up in a raku kiln. Unlike a regular electric kiln firing, the kiln heats fast enough that the pots don't have a chance to dry out before steam happens. When I used to do raku workshops, newly glazed pots were set on top of the kiln to dry out before they went into the kiln. Once the kiln was heated up from the first firing, the bricks held enough heat that the kiln would rocket up to 800F within a minute as soon as the door was closed without even turning on the burners, so pots were set into the kiln with the door open for about 10 minutes to heat up slowly at first at get that last bit of moisture out of them. We also set the pots on cold pieces of soft brick so as not to shock the bottoms, pulling out the hot ones after each firing and replacing them with cold ones.

I usually fire my kilns at night so I don't really see what's happening with actual temps in the kiln, but today I started it up in the morning and was in the studio in the evening and got to see exactly what was happening during the cooling cycle. I do a slightly-slow cooling cycle to even out the results in my 3 kilns because they all cool at drastically different rates due to their sizes. I do a drop from the peak down to 2000F, then cool at 175F/hr down to 1500F. This gives me identical results from all 3 of my kilns. This firing I'm talking about here is in my 10 cubic foot L&L EQ2827-3, which has 3 zones, and was packed very tight in the middle. I was surprised at just how much slower the middle cools compared to the top and bottom. This photo shows how it's going part way through the initial drop from peak temp to 2000F:

As you can see, the middle and the top are nowhere close to each other. In a normal firing segment, a 73 degree difference would stop the firing with an error code. So why isn't it doing that here? It's because the cooling rate is set at 9999, or full speed. Any time you use 9999, whether it's climbing or dropping, the controller lets the kiln do its thing and doesn't care if the sections aren't even. Firing up or down at 9999 is the fastest, but you sacrifice evenness. As the temp continues to drop, we see this:

Here you can see that the top section (TC1) has started firing again. The set point for this segment was 2000F, at which point it should start cooling at 175F/hr, yet the top section passed that by about 20 degrees before the relay kicked on and the controller stopped the drop. Why did it let it get so far below the set point? Because it's averaging the 3 zones. Once the average of the 3 zones hits the set point it will start to fire each section again as needed to match the set point.
I get a lot of questions from customers about error codes and cooling cycles. The biggest problem is that the kiln can't always keep up with the programmed cooling rate. There are a number of firing schedules out there on the internet that people are trying that use a rate of 600F/hr or more for the fast drop portion of the cooling cycle, and many kilns simply cannot cool that fast, especially the middle section. When you have a specific rate programmed, the controller will send out an error code if the kiln can't keep up with that rate. So if you want a really fast drop you should use 9999F/hr, not a specific rate. For most people doing slow cooling with cone 6 work it won't matter if the sections are not totally even during the drop. If you do need more precision, like if you're firing crystalline work and it's important that you don't overshoot any target temps, then you'll want to put in a slower drop rate that the kiln can actually keep up with, and the controller will keep the sections even and not overshoot set points.

In my experience, self-supporting cones can stick to the shelf if you overfire them just a little. They’re not supposed to, but it happens! As @Bill Kielb said, if you kiln wash your shelves, this is not a problem. I do not kiln wash my shelves, so I have had to chisel off some stuck cone bits. 
My solution to this is to use cone plaques, the kind that have holes in one side for holding non-self-supporting cones at the correct angle. I use the underside that doesn’t have holes, put kiln wash on that surface, and place my self-supporting cones on them. Any small piece of old or broken kiln furniture will work too.
 

Tiny tips one may have never seen, read, or heard 'bout before.
Flexible metal rib, ideal (almost) for moving insects on the surface of water/glaze/liquid to outside the Studio.
Tiny spiders, gnats, et cetera land on the surface tension - timely removal can prevent a tiny insectoid blob (and the bug can live on!). The rib's edge, just on the surface, allows the bug to change footing without wetting, nor harming them. Step outside, blow the bug gently off the rib, onto a rock, plant, or somewhat. Note the tiny antennae nod of thanks.
Using actual real chamois leather chamois*?
Is it floppy - stretched out - slimy and soft? When next you pour hot water into your throwing bucket, note that your chamois, when exposed to hot water, will shrink and "tighten up" considerably! ...maybe too tight? Don't worry, it will loosen up after while...
It's not rainy today!

*We have an actual leather chamois that was a gift promotion from an auto parts store, decades ago.
I've been trimming strips off of it for pottery use over the last six+ years...

@Retxy How much of what we're seeing is rusted metal vs old clay? If it's all metal, then the metal is in really bad condition and I wouldn't touch it. If we're looking at a bunch of clay on the surface and the metal underneath is still decent then I think sandblasting is probably the best way to go. Do not put any sort of coatings on the auger or in the hopper. They won't survive. Just leave the interior raw. Paint the exterior if you want to.

So the metal rod is the stem? First you'll need to decide what size rod you're going to use. Then when you make the flower, make a short hollow stem at the bottom of the flower that the rod will slide into. Make it big enough to allow for shrinkage of the clay. Make the stem a couple inches deep, and thick enough to support the weight of the flower. Then after firing you can glue the rod into the pocket using marine epoxy.

L&L just recently changed their recommended first firing schedule from cone 5 to cone 04. Either will work fine.
Probably because they still have a bunch of cone 5's to use up. Use them when you do your first glaze firing.  I'll talk to them about getting some 04's instead.
Personally, I would do an empty glaze firing (just shelves) with the 5's because if your glaze firing is running hot or cold you can ruin a lot of work.

Luckily there are a ton of online resources to help people do their own kiln maintenance. It's a lot less daunting than before the internet. Most of the kiln manufacturers have good online videos showing how to test, diagnose, and repair kiln issues. It's a good time to be a kiln owner!

It's not just a knob. It's specific to the Sitter, as it has a piece on it that triggers the shutoff. Google 'kiln sitter timer knob' for sources.

It's not just a knob. It's specific to the Sitter, as it has a piece on it that triggers the shutoff. Google 'kiln sitter timer knob' for sources.

It's not just a knob. It's specific to the Sitter, as it has a piece on it that triggers the shutoff. Google 'kiln sitter timer knob' for sources.

Hi @mattb, and welcome to the forum. It would help if you could draw a picture of your plans. Here are some questions I have based on my understanding of the project:
You're making it a downdraft, correct?
What is the btu output of your burners? Powered burners or venturi? Natural gas or propane?
What are you using for a safety system on the burners- Baso valve?
Why do you want to run everything through the electronics bay? Seems like a lot of hassle to work in there, and you'll be restricting airflow for the burners.
How do  you plan to construct the chimney?
Use 16x16 shelves. It needs space to breathe.
You can rewire the control transformer to run the controller on 120V if you want to use the thermocouple. I'd put the thermocouple in a protection tube or it won't last long if you plan to fire in reduction.
You can put the flue opening between the burner ports. Make the flue opening equal to the total area of the burner ports. You can always damper it down.
The bottom shelf will need to be above the burner ports. Have a bag wall for each burner under the shelf. Target bricks can just be a brick leaning against the wall at the end of the firebox, or a brick set upright but turned at an angle to the burners about 2/3 of the way from the burner.