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Everything posted by docweathers

  1. For however helpful in might be to someone else, I want to report back in on what appears to be the final solution to my burner problem. Jon Pacini of Laguna technical support suggested that I continue to reduce the orifice size down to a number 58 drill, which is a little smaller than 3/64ths. . Though I haven't done a full firing yet, with the lid open and at 7 inches of water pressure the flames are now about 10 inches high above the floor of the kiln. The top 1/5 th is yellow and the bottom 4/5 is blue. This seems about right to me. I want to thank all of the people on this forum, as well as Mark Ward and Jon Pacini, who offered much good advice. The least helpful people were Olympic Kilns Co. In fact, they were the real source of my difficulty given that the repeatedly asserted that 5/64 jet size was appropriate for propane on my kiln . Thanks to all Larry
  2. I have a pyrometer that accommodates 1 type k probe. I would like to add a second probe by having a switch to go from one to the other. Is it sufficient to have a single pole double throw switch to change the connection for one of the probe leads (while the other one remains continuously connected) or do I need to use a double pole double throw switch to change the connection for both leads simultaneously. I asked the vendor and I got basically a "darned if I know" Thanks Larry
  3. I talked to Ward today. He suggested reducing the orifice size from the factory recommended 5/64 to 1/16 inch. I have done this. When I tested it, I can run more manifold pressure, like 7 inches of water. However, it still begins to reduce strongly about 800°C as evidenced by yellow flames out the vent and my oximeter. It may be a little less reduction, but not much. This thing presents quite a puzzle for such a simple machine. What do you suggest? Thanks Larry
  4. That's a good idea? How would a smaller orifice be different than just keeping the manifold pressure lower? At this point, about 1/2 inch of water seems to be optimal for this contraption.
  5. Taking the flange out of the burner pipe did not help.
  6. my gauge reads in both IWC and pounds. in my initial post in this topic, I misstated pounds and what I should have said was IWC. since initial post I got my act together and have correctly stated everything in IWC. I took my burners out and disassemble them. the piece of pipe screwed in the top of each one of them had a significant flange on the inside, both top and bottom, from the pipe cutter that was originally used to make them.... 30+ years ago. This would appear to restrict airflow significantly. I took a reamer and cut this out of each of them and have reinstalled the burners. I am running a test right now, bringing the kiln, with some junk pots in it, up to temperature fairly quickly to see if this solved the problem. I am only at 400°C so far but things are looking better. thanks for your input
  7. You are right I was reducing too hard at some points. I have been corresponding with Olympic. They recommended 8 inches of water maximum pressure. If I even got to 1 inch, the reduction flames were huge. I sat for a long time fiddling with the gas pressure valve and watching the pyrometer. At something under 1 inch ( my manifold pressure gauge does not read well under 1) I was able to get to a maximum temperature of 974°C. If I increased the manifold pressure, the temperature actually started going down because the increased reduction.
  8. Thanks for all of the useful advice. As per JD3's post, I am pursuing getting a second pyrometer. What is the difference/advantage of the MR-750 Venturi burners over the original burners. I have one of the early versions of the Olympic 2728G Kiln which has six burners versus the current model which I think has four. Axner sells these burners for $43.50. With shipping I will be into this almost $300:huh:. I only paid $500 for the kiln, hood and furniture. I wonder at what point I start over with another kiln. I think my core problem is that my current burners are unable to mix enough air with the propane. Is there any way to get them to mix even more air or is there something that happens to them over time that restricts their original ability to mix air. (The air valve is wide open on all 6 of them) I have contacted great kilns, the manufacturer, and sent them detailed descriptions and pictures. Hopefully they will have some brilliant insights into how to fix this thing cheap. Does anyone know if this is a regular problem with this kind of kiln? Or, is this unique to my particular kiln? Thanks Larry
  9. Mark Thanks for your suggestion. I carefully adjusted the manifold pressure up and down to even get to 974°C. I was only able to get to that temperature by keeping the manifold pressure less than 1 inch of water, though I have 11 inches of water available. thanks Larry
  10. I just tried my first glaze firing in my used Olympic 2728G kiln. I got to 974°C and could go no further. The problem was obvious but the solution is not. The kiln was reducing strongly both as evidenced by 2 foot yellow flames coming out of the vent and my oximeter showing strong reduction. My manifold pressure was less than one IWC. When I would raise the manifold pressure the flames would get even taller and my pyrometer indicated it actually got cooler. I'm using propane. When I assembled the kiln, I checked the gas jet size and it was according to factory specifications for propane. I also cleaned each of the jets. I have the air control valves on all 6 burners all the way open. It seems obvious that I need to get more air into my burners but it is less obvious how to do that given that the air valves are already all the way open.:(I Suggestions please Thanks Larry
  11. I have had very good luck drilling glass with some diamond bits that I got from www.drillglass.com. I have not tried drilling ceramic, but I assume they would also drill ceramic.
  12. John In your picture you don't look older than God, but maybe you're well preserved:rolleyes:. I'll go ahead and buy Insight level II. thanks for your insight Larry
  13. I don't really need Insight right now, but they're having a 40% off sale. So, I'm tempted. Does anyone know if Digitalfire offers these sales from time to time or is this a one time deal? Thanks Larry
  14. I found a friend of mine, who turns wooden bowls and burns the waste. I have an almost unlimited supply from him. I build a nifty sifter out of 2 2 gallon plastic pails stuck one inside the other. I cut a large hole in the bottom of the top one and plastic welded some 100 mesh screen over the whole in the bottom. I stuck the two of them on my wheel, locked in my Giffen Gripper. I also built an arm, attached to a nearby shelf, that holds a stationary plastic paddle in the top bucket to stir the ash over the screen. The thing works great. I just dump some ash in the top bucket, let it turn for a while, then empty clumps out of the top bucket and the sifted ash out of the bottom one... repeat.
  15. I thought burn wood might be the answer, but sometimes you fancy potter chemists have something fancier in mind. Thanks for the suggestions.
  16. I see a number of glaze recipes calling for wood ash. What is the proper (easy) way to make this stuff for glazes? Thanks Larry
  17. My throwing area is a mess. Where can I find a picture of "Dennis Davis who built a frame around his wheel where tools could hang and slips used on thrown pots could be stored at hand." I need some tested ideas of how to organize my mess. Thanks Larry
  18. On YouTube I've seen some demonstrations of chattering on freshly thrown soft clay. It is still soft enough that they can expand the body of the pot to stretch the pattern. I've tried this with no luck. Any suggestions on how to get chattering to work on soft clay would be appreciated. Larry
  19. There also is reported to be a problem with the paper acting as a flux in the clay. Has anyone noticed this and dealt with it?
  20. I haven't tried paper play yet but I've been reading a lot about it. It sounds like it is the wonder clay that solves many common problems. So my question is, why doesn't most clay have a certain amount of paper pulp in it as standard practice? What is the downside of having a little paper fiber in all of your clay? I generally use Georgie's G mix 6 with grog.
  21. For what it is worth, I am experimenting with Axner Kiln Patch to mend cracks on bisqueware. Has anyone else tried this stuff?
  22. I like the definitive responses of yes both sand and grog, whatever you like that works for you;), it all depends on whether it's a sunny day or your foot itches:o. I too use a heat gun and have built a centering device that will let me quickly and easily center 20+ pounds of stiff clay. (I also do welded art, which also allows me to build strange tools for my pottery) I'm having to ask these strange questions because up until now the University always provided the clay, glazes, kilns and the "night trolls" to put it all together out of my sight and knowledge. Let me rephrase my original question. Why would a clay manufacture choose to use grog versus sand? thanks Larry
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