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David Woodin

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Everything posted by David Woodin

  1. The original glaze on the website you gave makes it difficult to convert because the Bentonite and Copper Carb are usually added as a % later. Therefore your glaze is slightly different than the website. At any rate it will run. should be Custer 49.92 Silica 17.2 Lith carb 4.05 3124 5.06 whiting 16.19 Stront 7.59 Total 99.98 Bent 3.04 Copper Carb 8.09
  2. I don't think the kiln completed its last ramp due to losing an element. That is why the old kiln sitter with timer were so valuable. David
  3. It is a Eurotherm/Chessel Model 2416/P4/VH/LH/XX/XX/XX/ENG it controls a Eurotherm solid state Relay 24amp. This is an industrial controller and maybe expensive. Other PID controllers could be used but you must make sure they have a guaranteed soak or hold back This means if you ramp to a temperature it has to stop and wait for the process to get there otherwise it could go though the whole program and think the kiln was following the program setpoint and the kiln might not be anywhere near the temperature. David
  4. As Neil said you probably have a defective controller. You can use a regular PID ramp soak controller but bear in mind that you will have to write a program and it will not have the same features as a Bartlett controller. I use an Industrial ramp/soak PID controller with excellent results. David
  5. The Rampmaster II is the same as other ceramic kiln controllers but has several newer features and a great price. David
  6. It Looks okay especially with a solid state relay. It looks like it is rated for 40 amps, so check your existing kiln for amp rating you may be able to get a higher rating from them. You will have to make your own program as It doesn't have the features of an Orton programmer, or any other programmer meant specifically for potters. Which means no sensing that the kiln is firing faster or slower than intended so no compensation for this and no guarantee of the proper heat work. Also all you are getting are the parts, you will have to mount them in an electrical box and run the power cord p
  7. A manual kiln with balanced elements can benefit from a Wall Mounted controller. On the other hand if your manual kiln doesn't fire evenly top to bottom (less than 1 cone difference), a Wall mounted controller can't help much except for the convenience. David
  8. I use a Bartlet controller to control 3 of my electric kilns one at a time. My kilns were manual so I changed the wiring of the kilns so that the controller bypasses the switches. Since the kilns have two rings I changed the Barlett to a 2 zone controller, and now have two zone control on each of the kilns. The Bartlett comes with the outputs all ready there for up to 3 zones and up to 3 thermocouple inputs.all of the same type. in my case type K. I have to change to which kiln I am using by means of the power cords and themocouples. It has been working fine for over a year now. David
  9. I just finished a slow glaze firing to cone 6 and a soak of 19 minutes, Total time of firing 7hr 53 min. Witness cones were self supporting cone 7. Cone 7 went down to 90 deg. I wanted 7 down and the glaze came out perfect. So the lesson here is be careful with the soak and use self supporting witness cones. Also the thermocouples have to be in good condition and you need to be sure as to what the thermocouple offset is set to, if at all. David
  10. L&L in there control manual doesn't recommend a hold time unless you are monitoring your kiln with cones. This means their controller is continually adjusting to give you the proper heat work as the elements age and your kiln loads change and the firing time changes. To be sure you are getting cone 5 buy some cone 5 self supporting cones and place in the kiln. As far as the bisque goes if you add a hold you are changing how much the clay body will absorb water and this could be a problem. The slow and fast bisque is designed to burn out the impurities in the clay which happens around
  11. Firing to cone 4 with a soak of 45 minute's will give you the same heat work as a cone 5 firing and cone 5 will go down. This is done in industry where a long soak is required. To refire a platter would be difficult unless you slowly bring it up to say 1800 F deg and then continue with a glaze firing. Any soak over 10 minutes is going to start on a path to overfiring. David
  12. Yes push the stop button David
  13. In most kilns a top shelf over everything helps. If you want to use a longer soak try firing to cone 4 and hold 45 minutes. But have a self standing witness cone where you can see it during the firing, so you can stop the firing if it is too long a soak. This certainly will tell you if a longer and slower firing is needed. David
  14. The peep being open could be a problem. Some more questions, is there a top shelf over the pieces? Is the kiln stacked so that there are at least 2 element between shelves? I would say the firing is too fast and another way to get a slower firing than the slow glass is to fire at cone 4 and hold until 5 goes down. If you might be interested I can give you a hold time that may do this. David
  15. Soak means a hold at top temperature, but anything over 10 minutes is going to change the heat work by a significant amount and the longer a soak will eventually get you into a cone 6 firing. You need to be using witness cones to keep track of what is going on. This is why I would write my own program, because your last segment was at 120 deg /hour. Unless your kiln has new elements it probably can't go at 120 deg per hour. The computer controller recalculates the firing based on how fast your kiln can fire within certain limits. My last segment in my user program is anywhere from 30 to 80
  16. Thank you Marcia, for the explanation. I changed it to 100% and than rounded the results to one decimal point and came up with 99.9% which hardly made any change to the original formula. Next step is for me to try it on my clay. David
  17. Out of curiosity is there some reason for Marcia's glaze not normalized to 100% David
  18. I think you only leave the top peep hole open for bisque firings. David
  19. for a consistency of 70. 1 pound water to 1.42 pound of pottery plaster or (70 parts water to 100 parts plaster ) could use 70 grams of water to 100 grams of plaster David
  20. Take a look at www.matrix2000.co.nz which is an on line glaze course. David
  21. Ramp is either time to get from one temperature to another or set as degrees per hour. You mentioned holding for 30 minutes at top temperature, this would mean you probably fired hotter than Cone 04. Most bisque is at cone 06. If you fire sculpture or heavy pieces slow bisque is okay otherwise I would use fast bisque and save 3 hours total time. The Orton 3000 is a great controller and you should look into making your own programs David.
  22. All the answers to this are good, One comment is that the kiln sitter was meant as a safety device for manual kilns. Somewhere along the line people started to use them to shut off the kiln without using witness cones, which also could cause overfiring problems. So on manual kilns a witness cone is what you should use to determine when to shut off a kiln. Small cones were made for the kiln sitter. Most kilns now use a programmer but again witness cones should be in the kiln.to be sure the temperature and heat work were reached. A 10 min hold for cone 5 will amount to about 14 deg F increa
  23. Matte glazes generally don't fall within limits. That was a big lesson for me in 2014. Limit formulas are mostly for glossy glazes for functional ware. You are correct. Michael Bailey in "Glazes cone 6" states that alumina matte glazes are temperature sensitive and plus minus 50 deg F can make them matt or shiny. So maybe if the witness cones are not the self standing type there could be a temperature difference that regular cones wouldn't show? David
  24. For a cone 6 glaze the recipe you gave doesn't have enough silica to be within the limits, the glaze doesn't add up to 100% and the fluxing power is very high so it could easily be glossy, the COE is also high which will cause problems on some clay bodies. That is why a Currie 35 grid test is helpfull, and probably will show several good glazes. David
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