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Me No Understand!


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I'm looking at different firing schedules for my kiln.

One I've looked at begins as follows:

1st ramp @ 50°F per hour to 220°F

I work in centigrade with my kiln so this converts to:-

1st ramp @ 10°C per hour to 104°C

If we start with an ambient temperature of 70°F it will take 3 hours to reach 220°F

 

Convert that to Centigrade:-

If we start with an ambient temperature of 20°C it will take 8 hours+ to reach 104°C

 

What am I missing?

 

:huh::blink::huh:

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You should just multiply by 5/9 for converting temperature differences or rates. (Or if you are lazy divide by 2).

So 50°F/hr = ~25°C/hr (a very slow ramp rate)

 

 

Here is my bisque program:

1. 150°C/hr to 100, hold 4-10 hours depending on the wetness and thickness of the work. I fire student work on a timeline and cannot always have it completely dry.

2. 150°C/hr to 400, hold 0.

3. 80°C/hr to 600, hold 0.

4. 150°C/hr to 1000, hold 20. About ∆06 I think. Change this final temperature/hold to meet your needs.

I have not lost a single piece using this program.

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You should just multiply by 5/9 for converting temperature differences or rates. (Or if you are lazy divide by 2).

So 50°F/hr = ~25°C/hr (a very slow ramp rate)

 

 

Here is my bisque program:

1. 150°C/hr to 100, hold 4-10 hours depending on the wetness and thickness of the work. I fire student work on a timeline and cannot always have it completely dry.

2. 150°C/hr to 400, hold 0.

3. 80°C/hr to 600, hold 0.

4. 150°C/hr to 1000, hold 20. About ∆06 I think. Change this final temperature/hold to meet your needs.

I have not lost a single piece using this program.

 

The very slow rate was what caught my eye, I don't intend to use the programme but couldn't help but convert it - in my head initially.

 

I knew that 50F is 10C and it just didn't work.

 

Usually, to convert F to C you first take off 32 then divide by 9 and multiply by 5.  It seems that to calculate something like this you ignore the initial -32 and then it works.

 

I usually fire both bisque and glaze @100°C to 600°C and then my programmes diverge  -  my work is always dry,  if it's at all suspect I'll do a separate candling first  to make sure  -  I've not had any problems but was just looking to tweak the glaze firings.

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It seems that to calculate something like this you ignore the initial -32 and then it works.

 

 

Correct.  

 

There's an old thread of mine with the very same conversation, as I too was confused.  But, yes, apparently when converting rate of rise, you leave off the -32 and it all works fine.

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