Has anyone on here ever fired pottery?

[Cowley]

Yep this is a massive stab in the dark.

Mrs C is now the proud owner of a fully wired up kiln which we’ve loaded up with her various creations this afternoon. Unfortunately though it’s somewhat more of a complex process than I’d appreciated (ie you don’t just press ‘on’ and then retire to the pub).

I know it’s a long shot but if anyone has any advice I’d much appreciate it!

 

[61653 HTAFC]

I remember using clay in art class at primary school, but alas when it came to firing our magnificent creations in the kiln we weren't allowed to participate.

Elf & Safety gone mad, I say.

 

[lkpridgeon]

I have and we're just about to get a kiln too! Good luck with your pottery endevours

 

[WatcherZero]

Not done it since school either, as I understand it its mostly a trial and error process that relies on gaining experience with the characteristics of a particular supply of clay rather than hard science.

 

[Cowley]

Morning folks.

Yes the thing that’s completely flummoxed me is programming this control unit:


I was vaguely starting to get my head around how it works but then realised that you had to program different stages of heat and then cooling into it. She’s got earthenware to fire and I just don’t want a) mess the pots up, or b) damage the kiln the first time I use it!

 

[D365]

I remember using clay in art class at primary school, but alas when it came to firing our magnificent creations in the kiln we weren't allowed to participate.

Elf & Safety gone mad, I say.

Likewise here, but I thought it was more than just safety concerns. Other than our semi-regular pottery lady (who also taught at the local college), the teachers had a knack for exploding creations...

... as I understand it its mostly a trial and error process that relies on gaining experience with the characteristics of a particular supply of clay rather than hard science.

Yes these would be my closing remarks also. Don't start right off with anything that you'd want to risk losing.

 

[Acey]

Didn't Chelsea do that ?

 

[WatcherZero]

Morning folks.

Yes the thing that’s completely flummoxed me is programming this control unit:


I was vaguely starting to get my head around how it works but then realised that you had to program different stages of heat and then cooling into it. She’s got earthenware to fire and I just don’t want a) mess the pots up, or b) damage the kiln the first time I use it!

Yeah as D365 said practise first on what you dont mind messing up. From a quick read on the subject Kilns seem to be pretty rugged but one danger is is you program them to ramp past their maximum output, e.g. maximum operating temperatures are generally just over 1300 degrees but yours works on setting target temperatures and ramp rate to reach it, rather than rate of increase and number of hours to maintain that rate of increase so you shouldnt risk burning it out that way unless you ran it for a long time at a target temperature of 1300+. Once youve set the programs it should be just like selecting a washing machine cycle, the pain is you have to initially program those cycles! Check if the controllers it Has come loaded with any preset programs which would save you the work.

Start the firing with the clay bone dry as the first slow heating stage is all about getting rid of the remaining moisture.

Below is an image that shows a common firing pattern (several sites I looked at had similar) In your programmer to set that up to match program 1 below that would be a two segment program.

Segment 1
Delayed start time = 0
Ramp rate 80 celsius/per hour
Target temperature 600 degrees
Soak time 10 minutes
Segment 2
Delayed start time 0
Ramp rate 200 degrees per hour
target temperature 1000 degrees
soak time 10 minutes

That firing should take just under 10 hours
The kiln will then slowly cool down until its under 40 degrees at which point it will say End. Soak time appears to be giving allowance for the temperature in the Kiln to reach and maintain those levels, on older kilns it might be 30 minutes but on newer better insulated kilns 5-10 minutes seems fine.

 

[Cowley]

Yeah as D365 said practise first on what you dont mind messing up. From a quick read on the subject Kilns seem to be pretty rugged but one danger is is you program them to ramp past their maximum output, e.g. maximum operating temperatures are generally just over 1300 degrees but yours works on setting target temperatures and ramp rate to reach it, rather than rate of increase and number of hours to maintain that rate of increase so you shouldnt risk burning it out that way unless you ran it for a long time at a target temperature of 1300+. Once youve set the programs it should be just like selecting a washing machine cycle, the pain is you have to initially program those cycles! Check if the controllers it Has come loaded with any preset programs which would save you the work.

Start the firing with the clay bone dry as the first slow heating stage is all about getting rid of the remaining moisture.

Below is an image that shows a common firing pattern (several sites I looked at had similar) In your programmer to set that up to match program 1 below that would be a two segment program.

Segment 1
Delayed start time = 0
Ramp rate 80 celsius/per hour
Target temperature 600 degrees
Soak time 10 minutes
Segment 2
Delayed start time 0
Ramp rate 200 degrees per hour
target temperature 1000 degrees
soak time 10 minutes

That firing should take just under 10 hours
The kiln will then slowly cool down until its under 40 degrees at which point it will say End. Soak time appears to be giving allowance for the temperature in the Kiln to reach and maintain those levels, on older kilns it might be 30 minutes but on newer better insulated kilns 5-10 minutes seems fine.

@WatcherZero - You’ve explained that in way that actually makes sense to me now. I’ll have another go at it after tomorrow when we’re both at home and see what happens. Thanks very much for the input.

Edit - just to add, I did check it for preset programs but it doesn’t seem to have any. Although if I can get it working then it should at least save this first one.

 

[WatcherZero]

@WatcherZero - You’ve explained that in way that actually makes sense to me now. I’ll have another go at it after tomorrow when we’re both at home and see what happens. Thanks very much for the input.

How did it go, tried it out yet?

 

[westv]

Sounds like one of those "buy it now and worry about how to use it later" sort of moments.

 

[birchesgreen]

I remember using clay in art class at primary school, but alas when it came to firing our magnificent creations in the kiln we weren't allowed to participate.

Elf & Safety gone mad, I say.

Same here, i mean what possibly could have gone wrong?

 

[Cowley]

How did it go, tried it out yet?

We’ve actually been away for the last couple of weeks so not had a chance yet. Definitely going to have a crack at it next week though.

Sounds like one of those "buy it now and worry about how to use it later" sort of moments.

Very much so.

 

[Gloster]

We’ve actually been away for the last couple of weeks so not had a chance yet. Definitely going to have a crack at it next week though.


Very much so.

I am not sure if ‘crack’ is the most suitable word.

 

[Cowley]

How did it go, tried it out yet?

Finally it’s time for a kiln update.

With the helpful advice above and a bit more research I programmed in a firing cycle, we filled it with some pots, pressed start and…. Nothing.

Ah.

I rechecked everything and it was just completely dead. So I phoned up our local clay supply place and they gave me the number of a company in Plymouth who repaired kilns. I sent them a video of it and they sent a chap out to look at it a couple of weeks later and this was what he found:

1) The kiln had been upgraded at some point with more powerful elements.
2) It originally had the controls on the actual unit and when it was upgraded they blanked that off and replaced it with the ST315 controller mentioned above which shows what it’s currently doing/the temperature it’s at etc.
3) It had a loose wire in the controller hence it not working.
4) The 13amp switched fuse that we’d fitted would very much not cut the mustard as the kiln had been upgraded and would (I think) be drawing the best part of 30 amps now!
5) The kiln works though and the chap programmed in a firing cycle for me and explained how it functioned.
6) He suggested that we only fire it when we can keep a close eye on it. So no going off to the beach for the day if it was running…

So the next free weekend we had, we loaded it up and pressed GO!

It climbed up to 600 degrees C slowly and at that point we were told to cover the vent at the top as any moisture etc would have escaped.
Then it climbed fairly rapidly but at reaching 1100 degrees C it threw up a fault code (error 7) saying that the temperature around the unit was too high. It was getting late at that point so we just switched it off.

The next evening once it had fully cooled we examined the pots and to be fair they seemed pretty well fired (we’d set it up to go to 1240 degrees C).

Obviously some of this is trial and error though, so we had another go yesterday after Mrs C had glazed those same pots.

Yesterday the same thing happened but at around 900 degrees this time. I’d moved the control unit out of the booth a couple of days ago as when I’d phoned the kiln chap again he’d suggested that the controller was possibly too near to the kiln and it wasn’t happy with the heat around it. It’s now mounted on a bracket on the door though and it still did it…

Once the kiln drops down to 600 degrees after the error code it fires up again and starts to climb back up, having handled the controller though I think I might have worked out what’s happening. I think it’s trying to ramp it up too quickly and the electrics in the box are getting too hot. I’m going to adjust the ramp settings for the next time we fire it as I think that might cure the problem, but I’m pleased to report that despite the issues last night we did eventually get it up to 1240 degrees C and complete the program!

Obviously you can’t open it until it’s all completely cooled down as everything will crack, but here’s Mrs C’s first properly fired pots!



This has all been quite the learning process but I think I’m starting to understand things now. Some of the ones we fired she actually made a while ago and she’s been making better stuff since then so it’ll be interesting to see what they look like once they’re done.

We’re just having a celebratory (pottery) glass of wine out of one them now.

 

[WatcherZero]

Congratulations, glad you've had a couple of successful fires though sounds like its been a nightmare.
Maybe next on the shopping list is a nice reliable car, like a Triumph TR6, lol.

 

[Cowley]

Congratulations, glad you've had a couple of successful fires though sounds like its been a nightmare.
Maybe next on the shopping list is a nice reliable car, like a Triumph TR6, lol.

My neighbours’ got one of those!