Blank ring to powered ring

[cadenrank]

Hey everyone. This is unrelated to my previous topics, but am curious. How difficult would it be to turn a 4.5 inch blank kiln ring into a ring with power instead? I’ve had an old blank ring that I use for bisque sometimes on an older manual kiln, but it’d be cool to make it a powered ring to stay there permanently. I think the control box is what I don’t know how I’d go about doing if I wanted to. Brick and element would be straight forward I think. But I guess I’d have to have a control box fabricated, and get its own switch, etc.? 
 

This isn’t a project I’m planning on doing yet, just thinking about it in passing every so often. 

[neilestrick]

First you'd have to groove the bricks, which isn't necessarily an easy or fun job. To power it you would need a box of some sort on the outside to cover the wiring connections and house a switch (or add a switch to the main box), and you could connect it to the main box with an external jumper cord on the ring and an outlet on the main box. From there it's just a matter of making all the connections. Doing this will increase the amperage draw of the kiln, so you'll probably have to upgrade the breaker and/or wiring and maybe the power cord, too.

[JohnnyK]

This sounds kind like the 2 mugs I've had in a damp box for the last 8-10 years and wondering when I'm going to end the test and fire them. I think about it whenever I use the damp box (which isn't that often) and say to myself, "Just a little longer"...

[cadenrank]

32 minutes ago, neilestrick said:

First you'd have to groove the bricks, which isn't necessarily an easy or fun job. 

I was imagining just getting new bricks for it. The cost for the bricks is really the only thing that has kept me from deeply pursuing this project, lol. 
 

33 minutes ago, neilestrick said:

To power it you would need a box of some sort on the outside to cover the wiring connections and house a switch (or add a switch to the main box), and you could connect it to the main box with an external jumper cord on the ring and an outlet on the main box.

This is the part that has been the biggest piece of the puzzle for me, the box that would cover the connections and house the switch. Where does one get something like that? Or how does one make one? Connecting it would be easy, since this kiln uses external jumpers and plugs anyways. 

Power consumption I guess would depend on element configuration. New kilns that would be of equivalent size to this one if I added the blank ring are within the specs of the existing wiring/circuit. And the power cord is a 50 amp appliance cord, so it should be good in regards to capacity as well. 

Thanks for the thoughts! This really just has been a floating idea in my head for the past year or two, but am just trying to solidify the details to determine if I should just throw that idea away, or continue thinking on it lol. 

[cadenrank]

30 minutes ago, JohnnyK said:

This sounds kind like the 2 mugs I've had in a damp box for the last 8-10 years and wondering when I'm going to end the test and fire them. I think about it whenever I use the damp box (which isn't that often) and say to myself, "Just a little longer"...

Yep, that's exactly what this is lol

[neilestrick]

9 minutes ago, cadenrank said:

I was imagining just getting new bricks for it. The cost for the bricks is really the only thing that has kept me from deeply pursuing this project, lol. 

So you'd just be using the metal band?

10 minutes ago, cadenrank said:

This is the part that has been the biggest piece of the puzzle for me, the box that would cover the connections and house the switch. Where does one get something like that? Or how does one make one?

You could make one from sheet metal, modify a box from another kiln, or find an electrical enclosure that would fit. You might have to make mounting brackets.

[neilestrick]

Is it a single row blank ring, 4.5" tall? Depending on where the elements come through, you might be able to stack a couple of 4" electrical box extension rings. The knockouts would make it easy to mount the jumper cord. Put a blank cover on the top and mount the switch in that. Kinda shim-sham, but it would serve the purpose and be as safe as anything else if it's securely mounted to the kiln.

[cadenrank]

Yep. It's a single row 4.5 inch. I guess where the elements would pass through would be up to where the holes in the terminal bricks make them come through. I'd have to drill the holes for them in the band. But yes, essentially, my idea of the project was just that I'd be using just the band. While I'd love to save money and do the brick grooving work myself, I feel that I would mess that up, and probably end up needing to buy bricks anyways. 

I was wondering about electrical box extension rings. My only concern with them was that there was no venting of any kind in the metal, and I wouldn't have any kind of air baffle between the band and the wiring/switch unless I made one of those as well. Of course everything would be high temp stuff inside the box, but I'd still feel more comfortable if it wasn't basically a mini oven inside the enclosure, lol. I guess I could drill out some vent holes on the top and bottom of the box depending how it's constructed. 

[cadenrank]

So electrically, lets assume I added a single 10ohm element to the configuration in the blank ring, 

It's currently running 2 ,10 ohm elements in series in each section at 240v. 
So that's 12 amps in each section, currently running 24 amps in the whole kiln. 
Adding another 10 ohm element in the blank ring would bring that to... a number that I'm not sure if is correct lol. 

we had discussed in another thread, about when I change elements next, to bump it up to 35 ohm elements wired parallel, which brings the amperage to around 27.42 for the whole kiln, and adding a 5th 35 ohm element would bring it to about 34.28 amps with the 35 ohm configuration. This would mean that I would need a 45 amp breaker with this configuration. Which isn't what's in place.  I'm assuming 8 gauge wire would also probably not work for a 45 amp circuit, but that's just an assumption.

Again, this is all hypothetical, and could vary on a lot of things that may or may not happen between now and if I ever do the project. Just getting an idea. This kiln would be the size of a Skutt 822 if I did this project, and the tech specs on that kiln would work in my current power available to this specific kiln, but am not sure how they got those values/ what resistance the elements are in that model. 

[neilestrick]

2 hours ago, cadenrank said:

we had discussed in another thread, about when I change elements next, to bump it up to 35 ohm elements wired parallel, which brings the amperage to around 27.42 for the whole kiln, and adding a 5th 35 ohm element would bring it to about 34.28 amps with the 35 ohm configuration. This would mean that I would need a 45 amp breaker with this configuration. Which isn't what's in place.  I'm assuming 8 gauge wire would also probably not work for a 45 amp circuit, but that's just an assumption.

This would be the best way to do it. You'd need a 50 amp breaker with #6 wire. It would be a cone 10 kiln.

2 hours ago, cadenrank said:

It's currently running 2 ,10 ohm elements in series in each section at 240v. 
So that's 12 amps in each section, currently running 24 amps in the whole kiln. 
Adding another 10 ohm element in the blank ring would bring that to... a number that I'm not sure if is correct lol. 

A single 10 ohm element at 240 volts it would draw 24 amps on its own. You'd need to use the 35 ohm element.

[cadenrank]

46 minutes ago, neilestrick said:

This would be the best way to do it. You'd need a 50 amp breaker with #6 wire. It would be a cone 10 kiln.

Just looking at the prices of 6/2 with ground cable compared to the 8/3 that I ran years ago, I wish I would have run the #6 wire at the start for this kiln. Were the calculations on this configuration correct? All 35 ohm elements, would be about 34.3 amps total with 5 35ohm elements running, two in each section wired parallel, and the single one in the blank?

 

46 minutes ago, neilestrick said:

A single 10 ohm element at 240 volts it would draw 24 amps on its own. You'd need to use the 35 ohm element.

That was what I thought. So, if I kept it in it's current configuration, 4 10 ohm elements, 24 amps for the existing section, putting a single 35 ohm element in the blank would bring it to about 30.85 amps total for the kiln. Which would keep the existing circuit of 40amp, #8 wire still able to work, correct? What would this be in a cone rating? 8? The kiln without the blank ring is rated to cone 8 on the manufacturers plate. I'm not sure if that's still accurate after changes to the switches and all of that. I don't know how the cone rating is calculated, I always thought it was just in relation to the brick and element type, etc. 

I'm mostly just trying to keep it cheap, but also functional. With brick and element and a switch, it's gonna be about a $200-$230 project alone. This number I'm okay with. Just to gain 4.5 inches at cone 6, haha. Granted, adding new #6 wire and breaker would probably only add about another $200, and then changing all of the elements to 35 ohm would be about $240 ontop of all of that. So almost half the cost of a new kiln that size for 4.5 inches increase at cone 6.  

[neilestrick]

1 hour ago, cadenrank said:

Were the calculations on this configuration correct? All 35 ohm elements, would be about 34.3 amps total with 5 35ohm elements running, two in each section wired parallel, and the single one in the blank?

Yes, you'd be pulling about 6.8 amps per element, 34.3 total.

If you run #6 wire, you'll be set for any kiln up to 48 amps if you upgrade in the future.

[cadenrank]

@neilestrick What are your thoughts about the lack of ventilation inside of one of the electrical box extenders? All of the ones I see online have knock outs on every side. The control boxes that are on the kiln already are basically just sheetmetal bent in 4 spots, but I feel that that would be a lot more difficult than what I'm imagining to do without a brake. I like the electrical box extender idea, but them not being vented is a concern to me. 

[neilestrick]

32 minutes ago, cadenrank said:

@neilestrick What are your thoughts about the lack of ventilation inside of one of the electrical box extenders? All of the ones I see online have knock outs on every side. The control boxes that are on the kiln already are basically just sheetmetal bent in 4 spots, but I feel that that would be a lot more difficult than what I'm imagining to do without a brake. I like the electrical box extender idea, but them not being vented is a concern to me. 

You could use a washer or two as spacers at each screw- at the kiln, between the two extensions, and under the cover. The old manual kilns that had a box on each section of the kiln had very little venting, certainly not enough to create much draft through the box, so I don't think it'll take much. And/or remove the knockouts on the sides and put some perforated sheet metal over the holes on the inside. They sell decorative aluminum perforated sheets at the hardware store for about 10 bucks.

[cadenrank]

 

8 minutes ago, neilestrick said:

You could use a washer or two as spacers at each screw- at the kiln, between the two extensions, and under the cover. 

I like the spacer washer idea. I might use the perforated metal too. How would I attach the perforation to the electrical box? I unfortunately don't have the ability to weld it. 

Also back to the brick, If I did get all new 4.5 inch bricks that were grooved to the different styles I'd need, would it pretty much be a direct fit? Just loosen the old band, and replace the old bricks, then tighten it back together? I'm imagining I may have to do some sanding, but have never needed to buy brick before so I don't know. 

I'm at the very least gonna continue thinking on the concept and make notes of your suggestions. 

Your help is always appreciated! I'll likely find more questions if I determine this project to be something worth while, or will update if I ever actually complete the project. 

[cadenrank]

So, to zero surprise to me, me posting this topic had made me want to dive into the project, and I did. 

Bricks are on the way, as well as elements and a pilot light. I've fabricated a cool little control box out of the electrical box extenders, and an infinite switch, and was surprised how well it worked. I didn't use the washers to make gaps, as I felt the boxes mated weirdly enough to allow a good amount of air flow out, and the boxes them selves had 4 or 5 small holes drilled in them already as well around the knockouts. I even went ahead and got a pyrometer and thermocouple, and am considering how I could potentially add the thermocouple permanently into this ring as well, but that's a project for once all of the rest of it is finished.

So, the roadblock in the project is something that I anticipated: The tensioners on the band broke it's rivets when taking it off of the blank bricks. I was pretty sure that this was probably going to happen, so I looked at the cost for 4.5in, 8 brick bands early on when I ordered the rest of the parts, and found they really weren't all that expensive brand new with all new hardware. About $30 without shipping. 

So the question is: Should I just go ahead and add another $30 some into this project and get a new band with new tensioners? Or should I do it like the rest of the kiln (the blank ring I believe was a part of another kiln) and use a ratchet strap to tension them, and then use screws to hold the tension where the bands meet? I know the tensioners are likely the preferred method, just wondering if it would really make any major difference or not.

 

[Mark C.]

You could just use  SS sheet metal screws and some straps to hold it all together-but 30$ is not much to do it right

[cadenrank]

6 minutes ago, Mark C. said:

but 30$ is not much to do it right

That was my thought too. Went ahead and ordered it. I figure I can just keep the old band hanging around for something else. 

[cadenrank]

Alright, well, bricks showed up this morning, and my kiln is running a test fire to 04 right now with the blank ring installed and powered. 

I'll post some pictures of the set up later on, but I'd say it all looks nice, and will hopefully complete the test fire well. I'll test it to cone 6 sometime later this week.

For the time being, it's running the 35ohm elements in the blank, and the 10 ohm elements in series the two sections, for a total of about 30 amps. I do plan to change them all to 35 ohm elements in parallel in the future, or if it doesn't get to cone 6 in a timely fashion, but I will have to change the gauge of wire running to the kiln to do that project, and throw away the 10 ohm elements that are only 3 months old. But I will slowly work on that project, if I'm satisfied with the time it takes to get to cone 6. 

Two questions: Is it normal that when all of the switches are on high, the middle elements (35 ohm) glow orange a lot quicker than the others? And is it also normal for the middle elements in the blank to not buzz as much as the others in the sections at first? I originally thought I may have wired something incorrectly because the other existing sections buzz pretty loudly for 15 minutes or so after they first turn on, where this one is very very very quiet in comparison. I checked the wiring, and all was normal, and looked inside, and the other sections were only just starting to glow, where the blank ring was bright orange. In theory, this all makes sense to me, but just wanted to make sure it was normal. 

I have a picture of my constructed control box that I took before I had the bricks, but I'll take some other pictures of the rest of the project once I complete the tests. 

https://imgur.com/Igw4Vxt is the link to the picture of the control box. Simple, but it's pretty much exactly the same as the other control boxes, and is really all it needs to be. 

[neilestrick]

18 minutes ago, cadenrank said:

Is it normal that when all of the switches are on high, the middle elements (35 ohm) glow orange a lot quicker than the others?

The more powerful elements will likely glow sooner than the others.

19 minutes ago, cadenrank said:

And is it also normal for the middle elements in the blank to not buzz as much as the others in the sections at first?

Buzzing is random and never the same for each section. I work on some kilns that are really loud, and others I can barely even hear.

Looks good!