neilestrick

You can just run the empty glaze as the first firing. Medium-Slow with a 1 hour preheat.

To be clear, my sketches are top view. If you're using two venturi burners have them come up from the bottom. If you're using a single power burner have it come from the side. The bottom shelf should be an inch or so off the floor. The bag wall will need to be at least as tall as the top of the burner ports, probably a few inches above that. Trial and error indeed. It's going to force heat upwards before it can be pulled down by the flue, and protect the pots along the firebox.

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.

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.

Yes, if you have some.

If you have some cones, use them bottom and top.

From the edit screen, push the Graph button and it'll show you how long it should take.

L&L used to recommend the slow cone 5 with 3 hour preheat, but they recently changed it to 04 with a 1 hour preheat. Whatever you do isn't going to make much of a difference in the long run. What's important is that you do some sort of firing to season the elements. Put a few shelves in the kiln when you do the test firing.

I've been thinking about this some more. I think that if you really want to be sure that it works well, I would do smaller shelves and leave a firebox zone. There's a tendency to want to fill these kilns with as much shelving as possible, because that's how it worked when used as an electric kiln. But if you were building a gas kiln from scratch you wouldn't do it that way. While it can work with 16x16 shelves, it won't fire nearly as nicely or easily as it could/should. By using smaller shelves and leaving a firebox, it's going to fire much better, and have more options for making adjustments. Specifically, I'm thinking of the bag wall, which will undoubtedly need to be adjusted up or down, and so leaving enough space for that is important. If you go with a single burner you can bring it in from the side. If you go with two burners, bring them in from the bottom: This design leaves room for a 5-6" wide firebox, which is really about the smallest you can functionally go. The 2.25" wide bag wall is made of regular 4.5" hard bricks cut in half. It's narrow but stable. You could increase the size of the shelf all the way to the edge of the firebox by letting it sit on a short bag wall, and then put more bag wall on top of the shelf. Then you'd have a roughly 17x14 shelf all the way up. I've built little kilns like this and they fired beautifully.

I would be very concerned with the splits warping, at which point the brick slots will crack and the mortar joints will fail. IFB are not strong at all. I certainly wouldn't trust them to support the kiln shelves above, although that can probably be dealt with in other ways. The firebox is the hottest point in the kiln, and the burners blasting on one side of a brick is about as uneven a heating situation as you can get in a kiln, so lots of movement there. Alpine kilns used to use a silicon carbide kiln shelf as a bag wall, notched in to the front and back walls of the kiln. They always cracked the bricks where they were notched in, at which point you had to switch to free stacked bricks, which could move as needed during expansion/contraction.

Bring the burner in along one wall, and have the flue opening centered on the opposite wall. Put a target brick about halfway in.

CFM of the blower will depend on the btu output needs, but for something small like this a little 50cfm squirrel cage blower would probably work. You'll want to have a rheostat on it to slow it down. The nice thing about a power burner is you can resize the gas orifice and get a really wide range of output without making any significant changes to the setup. If you really want to make it safe, put a solenoid on the gas line and connect to it a high limit shutoff, in addition to the Baso pilot system. This is one of a pair of burners I built a long time ago for a gas kiln I no longer have. About 450K btu each. Baso, solenoid, rheostat, high temp shutoff, timer. About as safe as I could make it with off-the-shelf parts and without getting into complex and expensive control systems. These can get pricey by the time you buy all the parts, but they work well and are quite safe. Ward Burner Systems is a good resource for burner info.

The size of your burner ports will depend on the size of your burner tips. The port should be about an inch wider in diameter than the burner tip. The end of the burner should be set back from the kiln wall 1/4" for every inch of burner tip diameter. I don't know how you'll make a bag wall that's only 1" wide and stay standing. Typically the bag wall is made of hard brick, set on side, so 2-2.5" in order to be stable.

I've seen that kiln, which is why I don't think the electronics bay is suitable for the burners. It's probably too shallow to house the burners, and I don't know how you'll be able to get to them to make adjustments during the firing if they're enclosed. Plus you don't want anything to restrict air flow around the burners. I would cut out a big panel from the right side of the cabinet from kiln floor level to the top so you have a nice open space to work within. Make the chimney a full brick thick (4.5"), and put in a damper about 1/3 of the way up from the bottom. Baso with a simple thermocouple and pilot light like an old school water heater will work well and be a cost-effective safety system. Just thought- if you make a power burner (with a blower) you'd only need one, and it would also eliminate the need for a very tall chimney. The chimney height is the number one issue we see here on the forum when it comes to successfully firing converting kilns. Most of those use venturi (n/a) burners, which are cheap but require a good dose of secondary air to fire properly, which comes from a taller chimney. With a power burner the chimney doesn't need to be any taller than the top the kiln. Having the front wall of the controller cabinet would also allow for mounting a rheostat for the blower. This kiln is a much better candidate for conversion than the majority of kilns we see here. It should work well.

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.

Those are the best! Seriously, I want to eat that pot.

Nestle

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!

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.

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.

Murphy's will work okay on the wood. The smoother the wood is the better, though, so the plaster doesn't have anything to grip on. Tapping a bunch works fine. If you were making lots of mold then a vibrating system would be good, but for the occasional one-off you'll be fine. https://ceramicartsnetwork.org/daily/article/Plaster-Mixing-101-How-to-Mix-Plaster-for-Ceramic-Molds

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.

Looks like it's wired wrong. You've got a wire going from the relay to the element, then jumping to the other end of the element. Each element needs both wires from the relay. So the relay wires should go to one element, then jump to the other element:

Does the kiln have a safety switch on the lid? If so, it may be out of adjustment.

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.