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David Woodin

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Posts posted by David Woodin

  1. The Genesis controller has many great features.   My experience with it did not end up good and I returned it and they gave me a full refund.  As Dick White said they give no information as to what  some of there software changes mean to how it will react.  I felt like I was doing there testing in the field for them and that  this should have been done  before it left the factory. I finally gave up when they tried to convince me that the cycling was due to stray coming in on the thermocouple even though I kept telling them the old V6 worked perfectly.  I now have an industrial controller that is 100% better and a setup where I can monitor firing on my computer and  go back and review firings and just measure how long they take to see if there is a change in element s that require  replacing them.  I also changed over to solid state relays, no clicking of relays and a much longer life span on SSR"s with a tighter control.


  2. First you need to verify what cone each shelf is being fired to.  The  best way is to use self standing cones.  If you decide to use a hold than you also need to change the top temp you fire to. For example if the final ramp to temp. is 120 F than a 10 min hold would subtract 13 F from top temp., a 108 ramp  -16 F for 10 min hold.  Unfortunately this means writing your own program.


  3. From what I can see of the elements, it looks like it could be fired.  You can get an appliance cord from Home Depot that will work for the kiln. take a picture of the cord end you now have and see if that matches  the Home depot 240 volt appliance cord.  You will have to verify what the breaker is for the   existing appliance outlet 35 amp is needed.  Take a look at the connecting wires in the kiln and they can be replaced with appliance high temp wire available  at Home Depot or any store that sells parts for stoves or dryers.  The kiln on 240 VAC will draw about 1565 watts instead of the original 1500 watts.  The cheapest and best elements can be ordered from Euclids.com,  they also carry many parts for kilns.  If this scares you then you will have to get someone who repairs kiln's.



  4. I bought a Genesis controller as an upgrade to my Bartlett V6-CF.  The first firing with it just did what ever it wanted and overfired everything.  I called Bartlett Co. and their Technician was only  interested in proving their was nothing wrong with the controller, it was my programing.  Finally after firing twice more with just shelves and posts and cones in the kiln I pulled the controller and put the original V6-CF back in and fired a load of pots successfully.   Today I called Bartlett to return the controller, and was put thru to Dave Bartlett, he said a lot of upgrades had been made on the firmware and would I put it back in and he would step me thru it.  This afternoon I called him again and had put it back in.  First I had taken down the information on the controller, He said that was the newest version, and after much talking back and forth of what I was seeing, he said he wanted to check one more thing.  He talked me through how to get to the PID and the setting was at 1 he said change it to 18 and he thought that would solve the problem.   I am now firing the kiln with shelves  and it seems to be following the setpoint like it should.   This PID setting in my manual says don't change without askiing the kiln Mfg. 


  5. On 6/8/2017 at 6:02 PM, AndrewNorrell said:

    Hoping for advice on if I should continue testing, changing the firing schedules, or just choose a different glaze clay combo. Problems here are bloating and crazing.


    I used a clear cone 6 glaze to test on cone 6 stoneware. The 4.6 cubic foot electric kiln was mostly empty, which I think let to some of my issues. Also, this is a manual kiln with no pyrometer. My temperature estimates are based on color and cones.


    I used Heath A2V cone 6


    Silica 35.4

    Gerstley Borate 29.2

    Nepheline Syenite (Theoretical) 20

    EPK 6.6

    Strontium Carbonate 5.7

    Wollastonite (Theoretical) 2.5

    Dolomite. 0.6


    Cone 6 Stoneware


    Cushing's Handbook (#4 on p.38)

    VC Stoneware Cone 6

    OM4 25

    Goldart 25

    Hawthorn 25

    Lizella Red 10

    Talc 5

    Nepheline Syenite 10





    I bisqued to cone 05 ( thinking of switching to cone 06) moving slowly from 200 to 1000 F, but once I passed 1300 I put all switches on high til the cone bent like we do at the kilns at my college. Through research though, I found out moving fast just after crystolysis can trap organics in the clay and this could be the cause of the bloating during glaze firing.




    Firing to cone 6, I shot the kiln right up at about 300F an hour... All the way to cone 6... Not doing that again....


    I attempted to hold the cone 6 temp for 10 minutes, but like I said- no temperature readout.




    Results of the cone, test tile, and test mug are attached. Would it be wise to try this again with a slower schedule, or scrap the combo?




    I am curious as to how the cone is set, it looks like it is laid on something?


  6. I use an Omega 1/4" diameter Type K, in their High Temperature super Omegeclad protecting tube.  Go to www.omega.com, go to temperature than to thermocouple, go to product finder and look at (*) QXL.  The one I use is KQXL-14G-7 @$35.00  The -7 is custom and 7 inches long. Standard lenths are 6 ",12",18" I get way over 150 firings, and when they fail it is immediate because of the small gauge wire in the protecting tube.


  7. I use  one controller for 3 each 2 zone kilns and just plug in the the power to the kiln I want to use and plug in  the thermocouples for the kiln  I am going to use into the controller .  I use the thermocouple plug in connectors from Omega.com.  The only draw back is the possibility of forgetting to change the thermocouples.  The contoller usually will come up with an error signal of  FAIL and shut off the kiln if this happens.  I have been using this set up for over 5 years now.


  8. I think that you can follow Min"s program by using the  first time ramp as a slow ramp from ambient  to what will get you to 200 deg F, (2  hours 10 min from ambient of 75 deg F gets to around 200 deg F) than the second time ramp to get you to a temp you will set in the program, than the next two  time ramps to get you to the bisque temp you will set in the program.   In other words you don't have to use up your 2  setpoints for temperature  right away but can use ramp rates to get to blind setpoints.


  9. On 9/2/2017 at 0:57 PM, Brandee Ross said:

    I posted images with the green glaze, but I am having the same defect on all my glazes and some of them use a different base:

    Licrorice Mod 4 (MC6G)
    Ferro Frit 3134    26.00
    Custer Feldspar    18.00
    Talc        5.00
    Whiting        4.00
    Ball Clay    25.00
    Silica        22.00
    Red Iron Oxide    9.00%
    Cobalt Carb    2.00%

    Bright Sky Blue (MC6G Glossy Base 1)
    G-200 Feldspar    20.00
    Ferro Frit 3134    20.00
    Wollastonite    10.00
    EPK Kaolin    20.00
    Silica        18.50
    Talc        11.50
    Cobalt Carb    1.00%
    Red Iron Oxide    0.50%
    Rutile        6.00%

    French Blue (MC6G Glossy Base 2, same base as Rutile Green)
    Custer Feldspar    22.00
    Whiting        4.00
    Talc        5.00
    EPK Kaolin    17.00
    Silica        26.00
    Ferro Frit 3134    26.00
    Cobalt Carb    1.00%
    Rutile        4.00%

    Raspberry (Van Gilder)
    Nepheline Sye    18.00
    Ferro Frit 3134    14.00
    Whiting        20.00
    Ball Clay    18.00
    Silica        30.00
    Chrome Oxide    0.20%
    Tin Oxide    3.80%

    I know it is a bad time to think about your problem, but you are mixing different base glazes together when  you double dip.  You could probably get the same effect using the same base but changing the colorants.  there may be times that you have a Custer base and than a G200  or Nephline Sye base on top of it, for me this would invite trouble.  There is no reason why you are stuck with different bases to get what you want.  It will require some color testing but both glazes would be compatable.


  10. On 8/18/2017 at 10:30 AM, Brandee Ross said:

    This is a problem I have had intermittently since I started making pottery at home in 2010, and lately it seems to be happening to more pieces each firing. 





    1. Are these pinholes or blisters? Sometimes they are sharp on the edges.

    2. How can I correct this?


    Helpful (?) details:

    • I am doing a slow bisque firing to cone 04. I hold for 10-15 minutes at peak depending how tight I've loaded the kiln.
    • Bisque firing profile: 80/hr to 250F, 200/hr to 1000F, 100/hr to 1100F, 180/hr to 1676F, 80/hr to 1945.
    • Glaze firing to cone 6. I do a programmed "slow" firing on Bartlett controller to 2167F and hold for 15-20 minutes depending on load. Witness cones show cone 6 achieved.
    • Stoneware clay, made by a local manufacturer (all-purpose Goldart-based body rated cone 6 to 8. Contains 4.5% fine grog).
    • 10 cubic foot kiln, electric
    • Kiln is vented with a Vent-a-Kiln hood that is only 2 months old, replaced broken downdraft vent. Problem occurred with both vents.
    • Trouble occurs sporadically with all my glazes, which I mix. The green glaze recipe in example photos:
      Rutile green:
      Talc 5,
      Custer Feldspar 22
      Whiting 4
      Silica 26
      EPK Kaolin 17
      Ferro Frit 3134 26
      ADD Rutile (light) 6%, Copper Carb 4%
    • Happens on all types of work: mugs, bowls, etc. 

    I've read on the forum about correcting pinholes with a slower bisque but I feel my firing is pretty slow already. Do I need to slow it more? Why does it only happen to certain pieces? Sometimes two identical pieces glazed and fired at the same time in the same way result in one unblemished piece and one as shown above.

    Working from home on my own and really feeling out of my depth... and incredibly frustrated.


    Your glaze firing program doesn't agree with the Barlett slow glaze program, the temperature of 2167 F even with a 20 min hold woudln't be cone 6 , some where around cone 5 and cone 5.5.  You are getting cone 6 past 90 degree so your kiln must be going very slow.  How many hours is the firing? Two of the glazes on the next page are within cone 6 food safe limits. Bright sky blue and Rasberry.  So probably your clay is suspect.


  11. this glaze is the one used over slips to allow their color to show and the drawn lines show up white.  i use it a lot and love the effects.  it is very touchy, literally touchy.  if i touch the glaze it scars over and looks awful.  it is the reason i spray all glaze now.


    the problem is that it contains zinc.  the thing that wrecks green slip and turns it grey. i am grateful for  dick white who explained why any of the mason stains that contain chrome do not work well when zinc is in the recipe.  he gave me the list and we noticed that almost every color has chrome.  who knew???


    anyway, a different glaze expert suggested that since only 8.6 % zinc is in the recipe i might be able to eliminate it entirely.  i will test this but wonder if any of you with the glaze programs see any problem with doing this.  is there a substitute for it?  


    i want so badly to have the green slip made with my new copper carb come out green.  is it possible?




    charles counts translucent white glaze      cone 6


    silica                         5.6

    zinc                           8.6

    EPK                          15.4

    whiting                       18.8

    neph sy                      51.6


    thank you for looking.   see why i love it?

    You could take out the Zinc, it will still have the same AL/SI ratio, but it will be a different glaze and probably fire in the cone 7 range, it may be possible to use a frit to get more fluxing.  The new glaze brought up to 100% would be neph sy 56.5, whiting 20.6, EPK 16.9, silica 6.0 


  12. callie,  so sorry you have so much trouble with bubbles.  i wondered what zinc adds to a glaze since so many recipes have it.  fluidity sounds important for a glaze, i hope my removing it does not cause more problems than i have now.



    david, thank you, but i am confused.  (not an unusual condition.)  i do not have enough knowledge to understand why i need to adjust the silica.  the glaze is one that i have used since the 1970s.    charles counts used for many years before that and his apprentice, susan barnhart maslowski taught me to use it as she had put it on her work for many years as well.  we all fire(d) to cone 6 in electric kilns.


    i am only trying to eliminate the zinc which changes green slip or underglaze to gray.  and you are right, i do not know what a 20 grid biaxial test is or what it would accomplish toward my goal.  can you help me understand?

    The glaze you now have is not a cone 6 glaze and you fire to cone 6, to make it a cone 6 glaze you need more silica in the glaze.

    You could  try a  line blend to get the silica into the cone 6 range and keep the AL/Si ratio the same as you now have.  The easy way to do a line blend  is to mix   A    and  B  containers first (about 350 grams batch each

                                                                            NEPH 180.6      145.6

                                                                       Whiting      65.8        53.2

                                                                         Zinc         30.1        24.5

                                                                         EPK         53.9        89.6

                                                                        Silica`       19.6        37.5

    If You have a 60 cc syringe you squirt the glaze into 7 small cups as follows:       1   2   3   4   5   6   7  cups

       each cup has this recipe in it

                                                                                                                                 A 96  80  64 48 32 16 0

      Nep Sy  whiting Zinc  EPK Silica                                                                       B  0   16  32 48 64 80 96

    1  51.6      18.8    8.6    15.4    5.6

    2  49.9      18.2    8.3     17.1   6.5

    3  48.3       17.6   8.1     18.8   7.3

    4  46.6       17.9  7.8      20.5  8.2

    5  44.9       16.4   7.5     22.2   9

    6  43.3       15,8   7.3     23.9   9.9

    7  41.6       15.2   7        25.6   10.7

    You also could just make the above separated  batches.  they will start getting into cone 6 range at 3 on.  The 20 grid biaxial is a simplified curry blend, but it will have matte to shiney glazes at cone 6. The above line blend will be in the matte range you now like. Sorry for the confusion.


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