Help with choosing my first kiln!

[Smorzando]

Hello everyone, I’m new here and am in the exciting but daunting process of buying my very first kiln.

I am in the UK, for reference.

I’m looking at a Nabertherm 60-litre toploader, as they seem to be a good make, and quite energy efficient. I don’t have room for a larger kiln, and I am only a hobby potter, really, who also tends to make smaller pieces

My question is regarding the controller for the kiln. The controller that comes as ‘standard’ with the kiln is a B500 which has ‘Four freely adjustable segments’ and can store 5 programs. There is also an option to purchase an ‘upgrade’ of a C540 controller which has ‘Twenty segments’ and can store 10 programs. 

As a complete novice to kiln firing, I would like to ask more experience members if they think the ‘basic’ controller would be suitable, or is the upgrade worth it? For reference it is quite considerably more expensive - £372 ($453) to be precise!- which is probably money I’d rather invest elsewhere, although I wouldn’t want to regret not choosing it if it later turned out it would have been useful….

Thanks in advance for your help!  

[High Bridge Pottery]

It looks like holds are their own segments so you won't be able to get very complicated with the firings. Say you had some thick work and wanted to heat to 80c and hold for a few hours that would be two segments. One going from 0c-80c in 30 min and another segment holding 80c for 2 hours. Then you only have two segments left for the rest of the firing (which is possible)

Some people like to heat slower through quartz inversion (575c I think) or do a hold at top temperature or even a slow cool. You could do a bisque firing in 1 segment if it was 0c-1000c for 10 hours (100c per hour) but if you wanted to go 0-80c for 30 min, 80c hold for 2 hours, 80-550c for 3 hours, 550-600c for 40 min, 600c-1260c for 4.5 hours, 1260c hold for 20 min you are looking at 6 segments. It really depends how complicated you want to get. A glaze firing could be 1 segments with 0-1260c for 8.5 hours and done.

 

Not sure I explained the best 

[Smorzando]

2 hours ago, High Bridge Pottery said:

 

Not sure I explained the best 

You explained it well - it’s just that having never fired a kiln, I really have no idea how likely it is that I’d want to do such a complex firing! So I suppose I was trying to get some idea from more experienced potters if they find that they often need so many ‘segments’ to a firing, or whether four would be enough for most purposes. 

Both controllers come with four preset programmes - but I can’t find out what exactly these presets are, in terms of exact ramps, holds etc.

[High Bridge Pottery]

I could certainly get by with a 4 segment program and £400~ extra just for more segments seems like a rip off unless it has more extra features.

 

My typical bisque would be 200c per hour to 100c then hold at 100c for 30 min. 150c per hour to 1000c then hold at 1000c for 20 min which would be the 4 segments.

 

A glaze firing doesn't really need the first hold so for a cone 10 firing it would be 250c per hour to 1180c then 60c per hour to 1280c and a 20 min hold at 1280c. You don't have to hold at the end but they can help to even out the temperature in the kiln. You would change the last ramp segment depending on which cone you want as cones are specified as a rate of climb (either 60c per hour or 150c per hour) for the last 100c of firing to a certain temperature.

250c per hour to 1180c may be too much for thick work or large platters and end up cracking them so something like 100-150c per hour would be better.

 

You could even add a controlled cool to the glaze firing as my example above is only 3 segments. Cooling slower than just turning the kiln off is good for crystal growth, if you are looking to get into proper crystaline glazes then I would probably go with the 20 segment. Not something I have tried myself but I have read they need very particular firing profiles on the way up and down to get big crystals.

 

In the end it all depends on how you like to fire. More segments will give you more ways to try and solve issues with your clay and glazes but from my experience you never need the firings to be overly complicated with different ramp rates and holds.

 

 

 

 

 

[Smorzando]

27 minutes ago, High Bridge Pottery said:

In the end it all depends on how you like to fire. More segments will give you more ways to try and solve issues with your clay and glazes but from my experience you never need the firings to be overly complicated with different ramp rates and holds.

 

Thanks - that’s really helpful. I am thinking it is probably best not to overcomplicate things, certainly with my first kiln. And I’ve no intention of getting into crystalline glazes - I will have plenty to keep me occupied making ‘normal’ glazes, since I’ve never even made one before! So perhaps the basic controller will be just fine for my needs at present. 

[neilestrick]

4 segments will work for basic firings, but as mentioned above it gets tricky if you want to do holds. However, if you limit it to 1 hold per firing you'll be fine, and you really shouldn't need more than 1 hold per firing. When I bisque fire:

1. 200F/hr to 200F

2. Hold for however long I need to make sure the work is dry

3. 325F/hr to 1745

4.  108F/hr to 1945 (cone 04)

So 4 segments on your controller. You can easily do a glaze firing in 3 segments, or even 2 segments with a drop and slow cooling segment after the peak. It's a scam for them to make the better controller cost that much more.

[Smorzando]

16 hours ago, neilestrick said:

So 4 segments on your controller. You can easily do a glaze firing in 3 segments, or even 2 segments with a drop and slow cooling segment after the peak. It's a scam for them to make the better controller cost that much more.

Thanks Neil! That makes sense. 

To risk further over complicating things - I have also been looking at a Rohde EcoTop 60 litre kiln, which is very comparable in terms of spec - also 3.6kw, 16amp, similar internal dimensions. It comes, from the suppliers I’m intending to use, with a Stafford ST411 controller which has 32 segments and can store 32 programs, 

The cost difference between the Nabertherm with basic controller and Rohde with ‘fancy’ controller, is £190 (the Rohde being the more expensive). If I assume that four segments would be enough, are they any other advantages of the Rohde kiln over the Nabertherm? Build quality, reliability, etc? 

[neilestrick]

Looks like they both have solid state relays and similar construction. The Nabertherm kilns are difficult to work on since they cram everything into the shallow hinge system. If the Rhode has a panel that's easier to access, then it would be worth the money to get the Rhode. And really, 190 is worth the better controller even if everything else is identical. I would also check with both and see if they actually take advantage of the SSRs ability to cycle at 500ms. To have SSR and switch them slowly like mechanical relays is a waste IMO.

[High Bridge Pottery]

From a quick search it looks like the Rohde elements are about £100 cheaper too. I think I got the right models of kilns. Can't seem to spot what kind of thermocouple the Rohde is using but I would guess it's the same typeS as the Nabertherm.

Edited March 21, 2023 by High Bridge Pottery

[neilestrick]

9 minutes ago, High Bridge Pottery said:

From a quick search it looks like the Rohde elements are about £100 cheaper too.

Good point. I recently got a quote from Nabertherm for a full set of elements for a Top 220 (8 elements) for $2030. That's a mighty expensive element change.

[Smorzando]

I knew this would get more confusing !

The supplier I’m looking at buying from (Hot Clay, in the UK) recommends the Nabertherm in terms of customer service, from their experience of dealing with them.

And from what I can tell the Nabertherm uses two elements rather than the one in the Rohde which is presumably why they are more expensive? The price does vary by supplier and I found a price difference of about 25% in a quick Google search….

I am starting to think I may as well just toss a coin

[High Bridge Pottery]

It looks like the Rohde uses 1 long element over 4 grooves and the Nabertherm uses 3 elements over 6 groves. Never seen a design with 1 long element like that before.

I just mentioned elements because they are a consumable and don't last forever so will need replacing at some point. I wouldn't worry too much about the customer service, if the kiln arrives broken I would guess you are dealing with HotClay not the kiln manufacturer.

 

Rohde

 

Nabertherm

 

[neilestrick]

I'd get the Rohde. Better controller and cheaper elements.