Chantay Posted May 25, 2015 Report Share Posted May 25, 2015 I have read the following, several times: Using Orton Pyrometric Cones Cone Numbers 022-14 Behavior of Pyrometric Cones Typically, it takes 15 to 25 minutes for a cone to bend once it starts. This depends on the cone number. The cone bends slowly at first but once it reaches the half way point (3 o’clock), it bends quickly. When the cone tip reaches a point level with the base, it is considered properly fired. This is the point for which temperature equivalents are determined. Differences between a cone touching the shelf and a cone at the 4 o’clock position are small, usually 1 or 2 degrees. So if I understand this correctly, if I want to reach cone 5, and it is all the way down, and cone 6 has started to bend, then I have over fired by about half a cone. I am using large cones in a plac. Would someone please verify that I am understanding this correctly. Link to comment Share on other sites More sharing options...
Mark C. Posted May 25, 2015 Report Share Posted May 25, 2015 ok this is for large cones only lets say you want a perfect cone 5 end point fire-you would fire until the cone tip is equal to the base (almost touching the shelve) Thats assuming your kiln is shut off at that point and does not climb or is on hold -for this cone to stay and not bend more the temp needs to cool from that point forward.The tip is same level as botton of base (large cones only) If the cone 6 is bent a little you would not care as the fire is a cone 5 perfect end point. I can post some photos if you need them of end point cones as I have a zillion cones laying around fired(they are not cone 5) Mark Link to comment Share on other sites More sharing options...
rayaldridge Posted May 25, 2015 Report Share Posted May 25, 2015 Mark is exactly right, as usual. But let me add that if you have a glaze that looks good at exactly 5, and bad at 5.5, then in my opinion you need a new glaze. Good glazes should not be so sensitive to minor differences in heat work. Link to comment Share on other sites More sharing options...
David Woodin Posted May 25, 2015 Report Share Posted May 25, 2015 If cone 5 is down or 90 deg bend than Cone 6 shouldn't have deformed at all. Cone 6 at a ramp rate of 108 deg F/hr would start to soften at around 2195 deg F but cone 5 would have been down to 90 deg bend at 2167 deg F. As far as your glaze goes it probably doesn't care, probably cone 5 1/2. David Link to comment Share on other sites More sharing options...
Pres Posted May 26, 2015 Report Share Posted May 26, 2015 If ^5 is nearly touching shelf or equal to base, ^6 will be somewhere near 45degrees from straight up. Link to comment Share on other sites More sharing options...
Mark C. Posted May 26, 2015 Report Share Posted May 26, 2015 I'm packing two kiln loads and 5 orders from all of the pots today-I can post a few photos in a day on cones and 1/2 and whole end points. Mark Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted May 26, 2015 Report Share Posted May 26, 2015 There is an interesting article on digital fire about reading cones. http://digitalfire.com/4sight/education/interpreting_orton_cones_193.html Link to comment Share on other sites More sharing options...
neilestrick Posted May 26, 2015 Report Share Posted May 26, 2015 When the tip of the cone touches the base, you're there. The next cone up will have started moving, and the previous cone will be pretty flat. There will always be variations to this, but in general this is what happens. Soda, salt and wood firings can have crazy effects on cones. Link to comment Share on other sites More sharing options...
Min Posted May 26, 2015 Report Share Posted May 26, 2015 One caveat I would like to add is that all the info on tip touching base doesn't apply if you are using the large self supporting cones. Tip down to top of the wedge shaped support in that case. Link to comment Share on other sites More sharing options...
Colby Charpentier Posted May 26, 2015 Report Share Posted May 26, 2015 I've never understood describing cone behavior with clock or angle references. The cones tend to curl or bend in ways that there could be many interpretations of these terms... In the larger community firings, we draw the cones every check, and use a finger to signal behavior. There are terms such as stiff, soft, bent, touching, and flat that are rather helpful. What does 45 degrees or 1 or 2 o'clock mean? Are you guys imagining vectors between the base and the tip of the cone? And why? Link to comment Share on other sites More sharing options...
Mark C. Posted May 26, 2015 Report Share Posted May 26, 2015 I've never understood describing cone behavior with clock or angle references. The cones tend to curl or bend in ways that there could be many interpretations of these terms... In the larger community firings, we draw the cones every check, and use a finger to signal behavior. There are terms such as stiff, soft, bent, touching, and flat that are rather helpful. What does 45 degrees or 1 or 2 o'clock mean? Are you guys imagining vectors between the base and the tip of the cone? And why? colby check this out and you will see what the clock vectors mean http://digitalfire.c..._cones_193.html Link to comment Share on other sites More sharing options...
Chantay Posted May 27, 2015 Author Report Share Posted May 27, 2015 Thanks everyone. Highbridge, the article really helped. Ray, your right. I am wasting a lot of time messing around with a finiky glaze. Works at cone 5 slow ramp, over done at cone 5 1/2 med ramp. So I have gone back and studied my cone packs and kiln log. Everything looks good, but now I am confident about it. Using the kiln vent helped even out my kiln. The bottom shelf is still about a quarter cone cooler than the top but it is not a problem. When I pull the cones out of the kiln I mark them with the firing number and T, M, or B for top shelf, Middle, or Bottom. Detailed notes, change only one thing at a time, and be ready to trash a bunch of work before getting it right. Now you know what to do with that 100 bowls you made for practice. Next firing I get to see what happens when you accidently pour the freshly mixed glaze into the wrong bucket. I now have three gallons labled with a question mark. Link to comment Share on other sites More sharing options...
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