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ronfire

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Posts posted by ronfire

  1. When I have a full shelf with 1/2 above I will use 4 stilts that will allow the full shelf to sit flat. Then above that I can add 1/2 shelves and have the stilts line up.

    It can be a pain to have the 4 stilts work to have the shelf stable. I will check to see if my stilts are close to the same length, exchanging 2 posts beside each other or sometimes rotating the full shelf helps stop the rocking if you are close.

    In a glaze fire I usually get the full shelf supporting flat then remove and load the shelf below to reduce the debs into the glaze.

     

  2. I dip all the pottery I make in a clear cone 6 glaze. The problem I am about to face is I threw a pot to big to dip and pour out at 9" X19". 

    I was thinking of spraying the glaze but have never done that, I do have a spray gun with the pot on top but have never used it and don't know how much I have to thin the glaze.

    My other choice would be to pour the glaze inside and pour it out, then place the bowl upside down and pour over the outside and maybe brush the bottom. I know this would work but maybe spray would be better .

    Sure could do with some advise from others that have faced this issue.

     

  3. Update. After speaking to Tony Hansen at plainsman he was not sure why the glaze did not gel. Suggested it might be the well water and could have a seasonal change and is why it worked well before. The recommendation was to remove some water to thicken it up and use it.

    Just emptied the kiln and all the glaze looked great, was a relief as I was worried about the excess Epsom salt.

    Now if I could only get that glaze to work on the sinks, will have to try again.

     

     

  4. I tried adding vinegar to about 2 litres of glaze and it still did not gel with 5 cap fulls. Just ordered a new bag to be shipped here, might be scraping this batch. I have a call in to Tony at plainsman to hear his advise. Might be able to add some of this glaze to the new batch to thicken it but for the amount I gain might not be worth it. Oh well it is just money.....

     

     

  5. At this point I will only try on a small batch to try and save what I have. Adding Bentonite looks like my next move,I will also call Plainsman tomorrow and see what they have to say .

    Read  that adding the Epsom salt without dissolving it first works but has to get mixed well and have time to dissolve into the glaze.

    With the amount of Epsom salt added I should be able to stand on the glaze. I know that all the salt was dissolved after screening the glaze and not finding any solids.

    I sure do appreciate all the advise and help.

  6. If I recrystallize the salt and remove it I still need to thicken the glaze.  When I went to thicken the glaze I had some crystallized salt that I added boiling water to and thought it should have been enough  after that I added the salt directly.  Have to use this glaze in a few days and not sure what to do at this point. It would be a 6 hour drive to get more glaze and start again.  I know the specific gravity was 1.44-1.45 when I mixed it as I checked both with a hydrometer and scale weight several times.

    Think tomorrow I will pull out a couple of litres and add some dissolved salt and see what happens.

     

  7. I do have hard water but had no issues last time. I did add the salt in the crystal form and mixed it well and let it sit and mixed again. It sat overnight and is still thin. Just went out and ran all the glaze through a fine screen and had no  solids in it. The glaze temp now is at 62F and still not gelled. Not sure what to do at this point, might have to phone plainsman in the morning, wonder if they had a bad batch and missed something .

    What happens to the salt when fired? Does it burn out?

    Went out and did a better estimate and put in 300-500grams.

     

  8. I just mixed up a 40+ lb bag of plainsman G2926B clear cone 6 glaze. Mixed to a specific gravity of 1.44 as per directions for dipping.

    I am adding Epson salt to thicken but it does not seam to have very little effect. I should have kept track of how much I added but  did not think of it at the time. My guess is I added about 1/2-3/4 kg looking at the container.

    Does this seam excessive?  Is there a problem with adding a large amount of Epson salt to thicken? I am trying to get the glaze to a 2-5 second bounce back.

    I just seams I am adding more than usual but have never measured the salt ( will from now on to keep track)

     

  9. I increased the 2 holes in the bottom of the kiln to 5/16. I checked the kiln this morning just as it shut down on a cone 6, the kiln would still draw in air at that temp and the pipe to the fan was 86f.  I did not notice fume from the glaze fire  so the next firing will be a bisque and see if the small increase in hole size made a difference. I might then try to increase the mixing air until I get a good balance and not draw as much air into the kin as it does draw in a flame from a lighter to the inlet holes. 

    The good note is I am happy with how the items look coming out of the kiln as long as I do not place large items on the bottom shelf. Guess I just like to try for perfection in how the kiln runs and vents.

     

  10. Here is a pic of the mixing box, not very clear. There is a pipe that will slide on the inner pipe that has holes in it. Currently I have it set to have only 1 hole open.  With the amount of negative pressure in the kiln I am surprised at the fumes I get just before the kiln reaches the top temp for cone 04 bisque. It is most noticeable on a bisque firing. When I test with a lighter on a removed plug or at the to holes on the lid the draft will bend the lighter flame inward.  I would get a pic of it but cant find a standard type lighter that works now,

    The lid does not appear to shift open during firing, I adjusted the hinge to eliminate that problem.

    So far my solution is to not be in the shop at that time except to check on the kiln, that is ok but still don't like it. It has been much easier to deal with now with the new controller instead of a sitter.

    Wonder if it would be better to change over to a top vent system instead and not draw air into the kiln. It would not be hard to change the fan over and hang a movable hood.

     

     

    1530402477_ScreenShot2020-11-21at9_30_00PM.png.8c7b6f73607ac4628ec48daa7a95f6e4.png

  11. The kiln does have a single thermocouple and is at the midpoint of the kiln. All the elements will fire at the same rate as it is set to a single zone. Even if I set the kin for a slow bisque of 16 hours I still have the breakage on the bottom shelf of large items. The shelf is flat and the items placed on the shelf does not rock at all, also placed on alumina to help with drag issues and try to reduce breakage. On the large items firing I have  a slow cool of 200f per hr to 1000f and then have the fan shut off,  it usually takes at least another 12 hours to cool to 200-150f.

    I would think that with the controller set to SSR mode that the bottom element would not get that far ahead of the firing schedule. Now I wonder if I should have built the controller for 3 zones instead but being a wall mount it would get a lot more wiring.

    Now I get worried and just load a shelf of mugs or bowls on the bottom but at time I will only have large 14"-20" bowls or sinks to fire so I try again and have breakage.

     

     

  12. I cant find any information on the cfm of the fan, even the link Tom posted does not list it. the draft hole I have below the kiln is a 1" hole that is only 3/4 open. I used to have a 2nd kiln on the system so the Y is now closed off and all the joints are taped closed.

    The kiln will suck in a flame from a lighter all the time during the firing, this is why I do not understand why the fumes.

     

    Screen Shot 2020-11-20 at 4.02.42 PM.png

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