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Showing results for tags 'orton cones'.
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I have been trying to be scientific about arranging my firing schedule in a small electric kiln with a controller. I understand the concept of heatwork and use cones on all shelves in my kiln to monitor results. I soak at top temperature and fire down so want to compensate for the additional heatwork these procedures involve when I set the top temperature on my controller. I understood that this could be done by looking at the area under a graph of total heatwork, but having compared theoretical models using the Orton cone firing tables, if this is indeed the case, I must be missing something. The following example uses °C, as I am in the UK, and I am referring to the Orton theoretical temperature values. 1. In the Orton table Cone 7 is reached at 1237°C when firing at 60°C /hr, if this is a straight ramp, this would take 20.3hrs, assuming a starting room temp of 17°C ((1237-17)/60). If the x-axis is time and the y-axis temperature, the area under the graph is a triangle and can be calculated as (1237 x 20.3)/2 = 12,555 2. When firing at 150°C/hr cone 7 is reached at 1255°C. As a straight ramp this would take 8.25hrs ((1255-17)/150). Then the area under the graph is also a triangle calculated as (1255x8.25)/2 = 5179 SO, these areas which are supposed to represent total heatwork to achieve cone 7 are not the same. I am clearly missing something here. Can anyone help please. Thank you
Does anyone know what the packing material inside old orton cone boxes is? The new ones use foam but the old ones use some other lightweight particles/chunks. I have always mixed these with my clay when I am making cone packs and it seems to help the moisture in the pack evaporate faster. It is so lightweight and seems like it would burn out but actually creates a nice aggregate in the clay of the cone pack and I thought it might be worth mixing into a clay body for a nice variation.... if I knew what it was and where to find more!