ayjay Posted August 27, 2016 Report Share Posted August 27, 2016 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°FI work in centigrade with my kiln so this converts to:-1st ramp @ 10°C per hour to 104°CIf 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? Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted August 27, 2016 Report Share Posted August 27, 2016 They don't scale the same, 50f may be 10c but 100f is 37.777c, 200f 93.333c. I guess you can only look at them as ratios 1:4 and so on, so 25c/h up to 100c. Link to comment Share on other sites More sharing options...
MatthewV Posted August 27, 2016 Report Share Posted August 27, 2016 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. Link to comment Share on other sites More sharing options...
ayjay Posted August 27, 2016 Author Report Share Posted August 27, 2016 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. Link to comment Share on other sites More sharing options...
Chilly Posted August 28, 2016 Report Share Posted August 28, 2016 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. Link to comment Share on other sites More sharing options...
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