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R Fraser

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About R Fraser

  • Rank
    Advanced Member
  • Birthday 05/29/1961

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  • Location
    Three Lakes, Wisconsin
  • Interests
    Raku, functional ware, kiln building, Shino experiments, throwing, woodworking, Single malt scotch,

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  1. I thought is was like toilets flushing and tropical storm rotation, it depends on your location relative to the equator? Richard
  2. I too found finches book helpfull. The price on Amazon has got to be an error because that is where I bought mine and it was well less that 700 USD! Amazon was kind enough to offer to buy my used copy for 2.03 USD though! Talk about depreciation. Richard
  3. The Sandia Forge reported up to 30% improved efficiency if I remember corectly. Nils Lou suggested significantly increased efficiency with his recuperating power burner set up but I do not remember if he made any specific claims. I would be concerned that depending on the location of the recuperators and the temp of the exhaust gases a closed loop system relying on natural draft flow to feed the burners primary air the CFM flow of primary air may be low, possibly too low to offer any meaningfull cooling of the recuperators and thus the burner. This would also limit your ability to control the kiln atmosphere to regulating the secondary air flow. The more I think on it the more it seems that to use a recuperating design safely and effectively you are almost obligated to use a blower fed burner system. Nils Lou's book "The Art of Firing" has a nice schematic outlining how to set up a recuperating kiln burner using a power burner system along with a ton of other great kiln construction info, probably the greatest information density per dollar of any kiln building books I bought second only to Olson's Kiln book. The plans and breif outline on design are at the end in an appendix if memory serves.. This is a link to the ABANA web site with the forge plans: ABANA Forge plans Note that this is a very small volume chamber with very short primary air supply tubes to the atmospheric burners in more or less a closed loop design. Richard
  4. This sounds like a recuperating (spelling?) type furnace I first read about when making my first blacksmith forge, I found the plans on the Sandia website (many years ago). It called for oval stainless steel pipe(s) running through the exhaust vent that was then collected and used to supply combustion air to the burner(s). These were atmospheric burners, and it was a small furnace < 2 cubic feet. In Nils Lou's book "The Art of Firing" he talks about a similar design for a ceramic kiln, but it is using a power burner with the blower first running through a pipe matrix in the exit flue to pick up heat before feeding the burner itself. I would say that everything from the flue to the burner would have to be stainless steel. I do not think this would be easily to make safe or simple using atmospheric burners. Richard
  5. I just built a kiln of this size and to fire to cone 10 in 8 hours (roughly) it needs 320,000 BTU/Hr input, and I have 2 burners that are fueled by high pressure propane that will put out 150,000 BTU/Hr on 3.5 PSI. I have fired several times now and have to throttle back to make it to 8 hours. The design is mostly a modified Oregon Flat top design as discussed in Nils Lou book the art of firing. The Burner you have pictured looks like a MR 750 or MR 100 style burner, but as pointed out type of fuel and how supplied, your elevation, orifice size, size of supply pipe, regulator capcity all influence final burner output. Marc Ward is a super resource on burner questions. Here is a link to the thread I started when I finished my kiln; My First Kiln Build Good luck! Richard
  6. My Laguna Pacifica wheel actually came with the advice to spray the belt with a silcone based spray on lube periodically to keep it quiet. Seemed like it would make it more prone to slippage, but I never did have that problem. When the belt got noisy, like neoprene rubbing unhappily together a quick squirt made it retunr to silent running status. Richard
  7. I bought a ball mill from an EBay vendor that is very servicable for about 150.00. I have milled several rounds of glaze for Raku and cone 10 reduction using the "jars" made from schedule 40 PVC plumbing fixtures (6" pipe, closed end cap, reducer and rubber cap secured with a SS band clamp. I bought ceramic ball media from a ceramic supply vendor in 1 inch, .75 inch and 0.5 inch sizes. It seems to work great, and I have made my own jars since for far less than the EBay vendor was charging. I imagine over time some of the PVC winds up abrading off the inner walls, but I have assumed any present in the glaze slurry burns out early in the firing and have not seen any ill effects in fired ware. Richard
  8. I read a tip somewhere that you can use the same diffuser to mass produce bits of wadding from your favorite wadding formula, just roll it into the diffuser, let it dry a bit and invert. Presto! Never occured to me to make little itty bitty tiles. Could make a very cool mosaic with these! Richard
  9. I have a safety tip. Much of what is sold as "consumer grade" disposable gloves are not latex free, and you may have to read the fine print to know it. All health care facilities are now "Latex Free Zones" due to the risk of serious allergy developing over time to latex both in staff and patients. Significant allergy can occur often only after sustained chronic exposure. The non-latex gloves do not have the same degree of elasticity and in some cases the same feel as the latex based gloves. Make sure you look for latex free on the box, particularly if you know or suspect you have a latex sensitivty. When I work with seriously toxic stuff (ferric chloride,soluble lithium or barium salts) I have a set of reusable gloves made for use with toxic and or harsh chemicals that go almost to mid forearm. I rinse, dry and repeat over and over again. I do keep some nitrile purple gloves similar to what prehosptial personell use for barium or lithium containing glazes as they are much more robust and can be dried and re-used for a bit. I also collect shower caps from every hotel that puts them out to cover my banding wheel when spraying or sloppy glazing. The glaze pops off when dry. Richard
  10. I have a strong affinity for a Shinto style belief system when it comes to my kilns, and generally offer premium Sake or good quality single malt Scotch to my little kiln Kami cups. I also feel strongly that my kiln Kami do not like to drink alone, so after loading and before lighting the pilot burners I have a toast or 2 to the happiness of the kiln and its ware, and another wee dram to wish for a safe & happy firing. It is surprising that the Greeks felt they needed more antagonistic dieties than charitable ones when it came to their pottery. Richard
  11. I love mine, and the free wheel feature is actually pretty cool. I have not noted bogging when throwing larger bits of clay though I must admit I do not often ask the wheel to spin more than 30 pounds. It is very quiet. I like it much more than the Pacifica 400 I was using. I threw on Brents in a studio and prefer my Shimpo. Richard
  12. Thanks for this. I was pretty sure that the math was done for this. This info is very helpfull. Richard
  13. After enough electrical disasters (sawzall vs. 220 line on the far side of the joist, small electrical fire after 220 wire of new dryer- fire department not involved) to make most sensible people actually pay a qualified person to do the work you would think I would know better, and yet… I bought a new 10 CF electric kiln and put in an 80 amp breaker for the 220V service, and bought some copper cable the size of a baby’s arm to hard wire the kiln to the junction box. Now I know the conventions for electrical wiring i.e. green = ground, and the large green cable in the guts of the kiln clearly was firmly mounted to the case & stainless jacket, so of course it is the ground right? The 8 gauge cable had 4 colors in it, black white, green, and another one (red). So of course this would be easy. I went over it all twice before energizing the panel and the breaker, and the kiln panel made a test tone like all was Okeedokee. So, following the testing instructions I was going to check that all the elements operated correctly and set up the kiln vent and plugged it in. When I energized the kiln there was an impressive flash and rather acrid smoke followed immediately by a warm wet feeling in my pants. I turned off the kiln breaker and went to see WTF was going on. The Kiln vent seemed to stop working and on closed investigation I noted the ground wire of the kiln vent had magically disappeared after melting its way through the plastic insulation. There was no other damage anywhere on or about the kiln so perhaps it was faulty wiring in the kiln vent, and yet it worked fine until I powered the kiln breaker. So I thought I should check the set up and took the wall and breaker box apart. Turns out somehow the green cable was attached to not the ground but to one of the energized legs of the panel, so my kiln jacket was energized with ½ of the 220 voltage, the black cable to the other and the white (should have gone to the energized pole) to the ground/neutral. The flash was indeed the ground of the kiln vent vaporizing because of its proximity to the rather “amped up†kiln jacket and a whole bunch of eager electrons with no place to go. Now, I appreciate the fact that these electrons did not pick me for the best exit to ground, and that after such a terrifying experience I should have paid the electrician to fix my problems. For a whole day I considered giving everything to do with electricity away but a lack of common sense and mortality prevailed. I corrected the faulty wiring, checked it a second and third time, replaced the kiln vent cable with a new grounded plug (one that still had a green wire) and standing a more than safe distance used a broom stick to energize the breaker to the kiln. Everything worked perfectly, all 3 thermocouples worked fine, all solenoids functioned and all kiln elements lit up. I am happy to say the kiln has been firing flawlessly since. My wife has been spared the gory (or nearly gory) details on this.
  14. Wow, that is a very cool set up. I think instead of re-building this kiln this summer perhaps I will build some power burners. I do have a couple of questions: are you running natural gas or propane, if propane are you on 11in WC or high pressure. How did you determine the CuFt/minute for the blower to orifice match? Do you have an orifice chart? To do this my current build the high pressure pilots and Baso's were by far the most expensive part, but safety first. So I would need to base any power burner on the high pressure propane source if I want to include the pilots and Basos. I do have the Baso valve left over from the original burner ring from the Torchbearer and it is set up for 11in WC propane, and I know it still works, but it would be awkward to plumb it for 2 burners. I discussed the merits of high vs. low pressure with Mr. Ward previously and the choice really only mandates the orifice diameter and may affect the turn down ratio in the end. But for the best efficiency getting the orifice right is probably pretty important. Do you have a parts list for that build? What kind of flame retention nozzle is that? I like the inline design with the blower passing straight through. Did you say the orifice is directed away from the blower, as in following the airflow? Sorry to bomb you with questions…
  15. I asked Marc Ward about this when I was planning my Raku kiln and he felt positioning the burner in the middle aimed straight in was fine, as the high pressure burner generates alot of turbulance on its own. I was going to try to point it along a tangent to the kiln interior to swirl and mix it up inside but it would have been difficult to get it aimed that way, and the flame tends to hug the wall it is aimed along anyway. Straight in has worked great for me and if there are any "cool spots" in my kiln I have not been able to find them. My octagonal shelf sits on three 8 inch posts which puts the shelf about level with the surface of the brick and the flame path is straight between the silts. Richard
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