neilestrick

The kiln should be vented for both fumes and heat. That could mean an overhead hood, a ceiling vent that's sized for the kiln and room size, or either of those in combination with a downdraft vent.

The kiln should be vented for both fumes and heat. That could mean an overhead hood, a ceiling vent that's sized for the kiln and room size, or either of those in combination with a downdraft vent.

The first glaze should be dry to the touch (which could mean anywhere from a few minutes to a couple of hours), but not totally dry. Different glazes dry at different rates, so as you use your glazes more you'll learn when the best time is to do the second glaze.

The kiln will take 6-12 hours to fire up, then another 12-24 hours to cool depending on how big the kiln is and how much work is in it. So at best you have about 18 hours where it will be hot and could be a danger to the kids. Plus the vent will be running and that can be loud. So no, it's not ideal. That said, I work on a lot of kilns that live in the classroom and they seem to make it work just fine- by firing on days when they don't have a full schedule, or timing the firing so that it's hottest when the classroom isn't being used and it can cool overnight. Ideally it would be best to have it in its own room, but I get that that isn't always possible. By only working at low fire temps you can shorten both the firing time and the cooling time. At the very least you should invest in a safety screen like THIS. They're usually available through Blick and School Specialty, too. Another option to keep the kids away is to build a chain-link fence around it. Dog kennel panels work well.
How is the kiln vented?

The kiln should be vented for both fumes and heat. That could mean an overhead hood, a ceiling vent that's sized for the kiln and room size, or either of those in combination with a downdraft vent.

@cbjensen Sorry it took me so long to reply with more explanation of what I said. (I had two shows in the past two weekends, one of which was a travel show.)
I used to do a show that charged a percentage of my sales. This was great when I was starting out, because of the low risk. But after several years, my sales grew to the point where the show became far more expensive than comparable shows. I stopped doing it, and others like me also moved on. I would recommend the show to other newbies, due to the low risk. Eventually, the show figured out that their talent pool was restricted to those who wanted low-risk, thus the quality of their show, and their revenue, was suffering. This has a real impact on attendance and reputation. Their intention was not to be a lower-end, newbie friendly show. But that’s what it turned into. 
Shows like these DO serve a purpose in the art world, by giving a safe space for new sellers. If you decide you want this to be the intention of your event, that’s not a bad thing! Just understand that there will be a ceiling on your quality, revenue, and reputation.
You said “we are a community” but this presumes that every one of the potters has the same goals for their own work, which is probably not true. The longer you do this event, over time it’s natural that some of your members are going to pull ahead of others. I hope you can be supportive of that, rather than trying to define everyone as being the same. 
The show that I mentioned above tried changing their fee structure to “percentage with a cap at the high end.” For some reason, that did not work out for them. I suspect it didn’t work because they had been making all of their revenue from the high sellers, so the cap cut their revenue by too much. So they eventually switched to a “flat fee for everyone” format, but had to deal with much complaining from those who felt entitled to the low-risk format. It was a real hassle for them to change formats. And by then, it was difficult for them to get the high-sellers to come back. (I had already found plenty of better shows to do.)
So my advice is to start thinking ahead about the future intentions of your event. Do you want it to be a safe space for newcomers? Do you want to foster professional quality work? It’s difficult to combine both types of sellers in one event. So maybe the answer is, down the road, you will establish a separate event that is defined as professional-grade. Where the participants are not self-selecting, but rather they need to pass through an arbiter of quality (similar to a juried art fair), and with a fee structure that is more friendly to them, and probably more profitable for your studio as well.  

Definitely check out everything Bill recommends. If everything looks good, then I would replace the wires going into and coming out of the switches. If they're old they can cause overheating.

The kiln will take 6-12 hours to fire up, then another 12-24 hours to cool depending on how big the kiln is and how much work is in it. So at best you have about 18 hours where it will be hot and could be a danger to the kids. Plus the vent will be running and that can be loud. So no, it's not ideal. That said, I work on a lot of kilns that live in the classroom and they seem to make it work just fine- by firing on days when they don't have a full schedule, or timing the firing so that it's hottest when the classroom isn't being used and it can cool overnight. Ideally it would be best to have it in its own room, but I get that that isn't always possible. By only working at low fire temps you can shorten both the firing time and the cooling time. At the very least you should invest in a safety screen like THIS. They're usually available through Blick and School Specialty, too. Another option to keep the kids away is to build a chain-link fence around it. Dog kennel panels work well.
How is the kiln vented?

If you can't figure out the timer relay situation or can't get parts, you can just add one more 15 amp infinite switch, do away with all the relays, and wire each element set to one of the switches. If it were me, I'd go ahead and replace the old switch, too, so you're starting fresh with matching switches. Any 240 volt, 15 amp infinite switch kit will work. I like Robert Shaw brand. Make sure it includes the knob, because many don't.

If the timer shut it off before the cone dropped, then it didn't reach temp. Turn the kiln on high for a few minutes and see if all the elements glow. If one is out, then it's probably just a fried element. If two in the same section are out, then you probably have a bad switch. Or in both cases it could be a wiring connection fried out somewhere, which should be easy to see when you open up the control box (with the kiln unplugged). If they all glow, then they're probably worn and need to be replaced. Post a pic of the elements so we can see their condition.

Ahhhh! Thank you! When we did the offset we entered using the 9 not realizing that was a negative. The manual we were looking at didn’t explain it as clearly as these instructions you’ve provided and only showed the offset with the 9 (for example, 9020 for 20 degrees). I believe this is our problem! Our maintenance crew has all but given up. Thank you!!

@clayenthusiast Here's a recipe for Betty Woodman White, which is a very popular magnesium white that I've never seen have any problems on stoneware bodies. I used it for many years on my own work. Give it a try and see what you think.
BW White.pdf

I agree. The kaolin, silica, and bentonite make up almost 50% of this glaze. There's just not enough fluxing going on there. I'm wondering if there was a problem with converting the recipe at some point since the numbers add up in a strange way. Maybe someone messed up the math?

I have had lots of Amaco velvets color shift on me, especially the greens, even with glazes that should be just fine on them (no zinc). I have much better luck with Speedball underglazes. Looks like the Mayco is the way to go.

I agree. The kaolin, silica, and bentonite make up almost 50% of this glaze. There's just not enough fluxing going on there. I'm wondering if there was a problem with converting the recipe at some point since the numbers add up in a strange way. Maybe someone messed up the math?

I've always felt that charging a percentage of sales is good for a lot of the artists, but bad for the promoter. As an artist, it limits your costs if the show is a dud, and the percentage isn't necessarily penalizing unless you sell a lot of work. If you're someone who typically sells $5000 at a show, I can see how it's not a great deal compared to paying a flat $400 booth fee. But for someone who typically sells half that much it can be a good thing. I think you just need to do the math before applying and decide if it's a good show  for you or not. As a promoter, only charging a percentage of sales makes no sense because your costs for running the show are the same whether the artists sell a lot or a little, and it adds a lot of paperwork to the process. Flat booth fees are easy to deal with and easy to budget.

Teaching did more to improve my throwing skills than just about anything else, because I was forced to analyze everything I was doing in order to explain it to my students- hand position, body position, pressure, how I was holding tools, tool angle, wheel speed, etc, etc, etc. It was especially great for consistency, because once I could define exactly what I was doing I was able to repeat it every time.

I've always felt that charging a percentage of sales is good for a lot of the artists, but bad for the promoter. As an artist, it limits your costs if the show is a dud, and the percentage isn't necessarily penalizing unless you sell a lot of work. If you're someone who typically sells $5000 at a show, I can see how it's not a great deal compared to paying a flat $400 booth fee. But for someone who typically sells half that much it can be a good thing. I think you just need to do the math before applying and decide if it's a good show  for you or not. As a promoter, only charging a percentage of sales makes no sense because your costs for running the show are the same whether the artists sell a lot or a little, and it adds a lot of paperwork to the process. Flat booth fees are easy to deal with and easy to budget.

I agree with Bill. Keep the buss bars, replace  the other hardware. Buss bars seem to last forever even as the rest of the hardware corrodes away. The little square washer things can be replaced with fender washers. Use stainless steel hardware for everything. The bolts are probably 10-24, but take a buss bar with you to the hardware store to confirm. Splitting the ends of the element pigtails to go around the bolt is a real pain, so if you want you can just bend the end of the pigtail to go around the bolt. Also put new ring terminals on the wires, or replace the wires if they're old. Use high temp ring connectors, not the regular ones you get at the hardware store. You can find them online from a bunch of places.

Definitely not a good glaze for pieces that could be used for food, due to the crazing and poor durability. Raku glazes are generally formulated for a certain look, not for functionality. With low fire work you really want a glaze that fits really well if you're making functional work, or anything that is used around liquids, since the clay body doesn't vitrify.

Each section would have a mechanical relay and an SSR. The mechanical is turned on by the safety relay at the start of the firing and remains on until the firing is done. The SSRs are connected to the  controller outputs 1,2 , & 3 and get cycled on and off by the controller. I've attached a wiring diagram for a Skutt SSR kiln, which is how it should be done.
 
KMT1227-SSRPK-1ph-W_9601.pdf

If you are stuck or unsure they will crimp tight enough a mechanical lug can be a solution. Definitely available at most big box. Cut back the wire until you find nice copper.
 

I'd go wall mount. It'll be easier to work on and everything will stay cooler and last longer. The Duncan box will be a tight fit, and may not be deep enough for everything, plus you could use the wall mount on other kilns in the future. You'll still want a cooling fan in the wall mount, unless you have a large heat sink. A fan is much cheaper than a heat sink. The fan can connect to Output 4, or just run it in line with a power switch. Run mechanical relays in pairs with the SSRs, with the mechanicals being controlled by the Safety output on the  controller and the SSRs run by the Outputs. Use very fast acting Type T fuses for each circuit. The SSR control for the Genesis can be turned on in the Factory Config menu, use code 443.

@Sinead Pollard How thick is the piece? If you post some pictures that will help diagnose the cause.

@mxdsaIt's not simple to fully convert a manual kiln to a digital system because the control box on the manual kiln isn't made to house the digital kiln parts. There's no insulating baffle, and the box isn't necessarily deep enough to house the parts needed. You can't just replace the Sitter with a digital controller- there are other parts needed (a transformer and at least one relay- usually two or more). The easiest solution is to buy or build a small control box that houses all the parts and hangs on the wall next to the kiln. The kiln plugs into the control box, and the control box plugs into the outlet on the wall. You use the Sitter as a backup safety device by putting a cone in the Sitter that's one cone hotter than the intended peak temp, then push the power button on the Sitter and turn the switches to 'high'. Then you start the digital controller and it cycles the power to the kiln to control the rate of climb.
Here's a picture of a control box I built and installed for a customer last week. It has a Genesis Mini controller, which is perfect for this type of setup since it only uses one thermocouple. The power cord comes out the bottom, the kiln plugs in on the left. Inside is a 50 amp relay, and pilot relay, a transformer, and all the wiring to make it work. It's not simple if you've never dealt with wiring before, but the good news is that you can buy a complete box just like this, although it'll cost you more than $1000 with a touch screen controller. This box is hooked up to a Duncan kiln, which has an early generation analog automatic system that I had to disconnect in order to work with the digital controller. That shouldn't be an issue with your Knight kiln, though, as I've never seen one with anything other than simple switches.