neilestrick

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!

Gas combustion made simple! At about 10:1 air / fuel you will get a nice blue efficient flame (natural gas, propane not so much), plenty of oxygen for efficient combustion. A nice blue base of the flame is a reasonable indication of an oxidizing fairly efficient flame so the answer to your question is basically yes it’s a decent indication enough primary air is coming in. . Venturi burners are sort of self calibrated within a pressure range of operation so the more gas pressure, the more primary air is sucked in by the Venturi effect. Your burners do not appear to have a primary air shutter and that is ok really. A nice blue color, devoid of yellow indicates you are operating within a reasonable efficient pressure  range for this burner.  
About 50%:of the air for combustion comes from the primary air and 50% secondary air. The secondary air enters around the burner or the hole in the bottom of the kiln where the burner penetrates.
when closing the damper there will be an absolute best position for a given gas pressure where you are losing the least amount of heat but still allowing enough secondary airflow through the kiln for all the gas to be burned efficiently. Close it more and flame efficiency drops, less secondary air comes in the holes around the burners.
Folks often set their gas pressure -  then find the point where performance begins to drop and open their dampers slightly more from there to get near that perfect balance. Every increase in pressure generally requires a slight opening of the damper so patience is key until you learn about where the damper needs to be for a given pressure for your kiln.
Your stuff seems to be working as designed, I would’ suggest testing with a damper first, it seems you are close ……. before making changes to the original design. Meaningful fine tuning  damper adjustments start about 1000 degrees btw.
There always seems to be a lot of confusion with combustion
Simple Bunsen burner pic below we use to teach primary and secondary air and a fuel air chart showing efficient mixtures you might find helpful.

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 easier to overpower these little round kilns. Sometimes you need to back off the burners to get them to go. Also, what size shelves did you have in the kiln? You usually need to use a smaller shelf than what an electric kiln of that size would use, so there's room for air to flow. A lot of people also put a shelf at the top, like 3 inches below the flue opening. Even a short pipe over the flue will increase the draw. You can even make a small chimney out of stacked soft brick.

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.

It's easier to overpower these little round kilns. Sometimes you need to back off the burners to get them to go. Also, what size shelves did you have in the kiln? You usually need to use a smaller shelf than what an electric kiln of that size would use, so there's room for air to flow. A lot of people also put a shelf at the top, like 3 inches below the flue opening. Even a short pipe over the flue will increase the draw. You can even make a small chimney out of stacked soft brick.

It's easier to overpower these little round kilns. Sometimes you need to back off the burners to get them to go. Also, what size shelves did you have in the kiln? You usually need to use a smaller shelf than what an electric kiln of that size would use, so there's room for air to flow. A lot of people also put a shelf at the top, like 3 inches below the flue opening. Even a short pipe over the flue will increase the draw. You can even make a small chimney out of stacked soft brick.

They would probably be okay, but any time you shut down a glaze before it's gone through its complete melting cycle there's a chance of something going wrong like crawling. It would also depend totally on the glaze formula as to just how much things would harden up at low temps. I would just carefully wrap them in something soft and pack them so they don't move and rub. If you're using brushing glazes they tend to be pretty durable before firing anyway.

That's a cone 05, not 5. That would explain why the cone 5 glazes didn't melt.

Interesting stuff. The main thing it's missing is that the sodium is not just reacting with the silica. It also needs alumina in order for it to form the glaze. Pure silica will not be affected by sodium vapor. We used to dust flint onto our salt kiln shelves to protect them.
High zirconia blanket is about 15-17% zircon. It's in there primarily to bump up the heat rating of the  blanket. It may help protect from the soda, but not much. High zirconia bricks are 60+% zircon, so it's going to be considerably more durable than the fiber.
The life span of salt and soda kilns depends more on the amount of salt and soda being used in each firing than which one you're using. Salt kilns can outlast soda kilns and vice versa. In general, I see soda people using a lot more material than salt people.
Neither salt nor soda is more dangerous than the other, and your car will create many times more pollution than a salt/soda kiln being fired every week. Much of what comes out the stack is water vapor, and about 96% of the salt/soda that goes into the kiln comes out the stack as the same thing.
Read 'The Truth About Salt' by Gil Stengel in the Sept. 1998 Ceramics Monthly. HERE is some other good info. HERE is a good discussion.

I agree regarding the firing schedule. A shorter firing with holds in the proper places could cuts hours off the firing time, and probably reduce firing costs as well. The slow creep to 300F is totally unnecessary, especially if your work is dry. Just run it up to 200F or 220F, hold as long as needed to make sure everything is dry, then go for it. Also, that first ramp  can be a lot faster than 60F/hr, like 150F/hr will work just fine. There's no reason to take 2 hours to get to the preheat temp, because the hold is where you're really drying things out. 

Move it in sections, don't try to lift it all at once. Unhook and remove the lid. Stack the sections in the truck, making two stacks if you can. Put foam board underneath each section. The pink house insulation board works well. Set down the wall sections first, with the lid and floor slabs on top (if the floor is a separate piece). Foam board separating everything. Wrap it all up with plastic stretch wrap and secure the load as best you can. I use a cargo tarp and that works really well. If you put straps over the top, put foam board between the straps and the kiln. Don't crank down too tight with straps or you could crack the bricks.

A cleanup with a commutator stone will probably help a lot. Does the motor have a small access plate on the side?

I agree regarding the firing schedule. A shorter firing with holds in the proper places could cuts hours off the firing time, and probably reduce firing costs as well. The slow creep to 300F is totally unnecessary, especially if your work is dry. Just run it up to 200F or 220F, hold as long as needed to make sure everything is dry, then go for it. Also, that first ramp  can be a lot faster than 60F/hr, like 150F/hr will work just fine. There's no reason to take 2 hours to get to the preheat temp, because the hold is where you're really drying things out. 

All dark brown/black bodies do odd things with glazes. You have to do a lot of testing to find glazes that work well with them. Those that do can be really striking, though, especially if you leave areas of the clay body visible. My students use a fair amount of Standard 266, and it's a wonderful body to work with. Has a great feel. Don't go past cone 5 with it, though, or you risk bloating.

Ok, now download the firing log and feed that sweet thang into @jay_klay_studio's graphing program to visually see the tracks of the 3 sections. And if you really want to have some fun, add another 9999 drop all the way down to 100 after your regularly programmed cool to log how looooonnnggggg it takes for the last several hundred degrees. Several times over the years I've printed the extended graph of a few kilns as a teachable moment for the students of the virtue of patience, i.e., "Can I get my piece tomorrow?" "No, next Friday."

Move it in sections, don't try to lift it all at once. Unhook and remove the lid. Stack the sections in the truck, making two stacks if you can. Put foam board underneath each section. The pink house insulation board works well. Set down the wall sections first, with the lid and floor slabs on top (if the floor is a separate piece). Foam board separating everything. Wrap it all up with plastic stretch wrap and secure the load as best you can. I use a cargo tarp and that works really well. If you put straps over the top, put foam board between the straps and the kiln. Don't crank down too tight with straps or you could crack the bricks.

Those coatings may be beneficial in a typical reduction firing because they harden the surface of the fiber and make it more durable, but in something as corrosive as soda or salt it won't be able to protect it enough. The atmosphere is just too corrosive.

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.

That's a cone 05, not 5. That would explain why the cone 5 glazes didn't melt.

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.

That's a cone 05, not 5. That would explain why the cone 5 glazes didn't melt.

What color is the cone?

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.

That's a cone 05, not 5. That would explain why the cone 5 glazes didn't melt.