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Bill Kielb

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About Bill Kielb

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    Advanced Member

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    United States - Illinois
  • Interests
    All forms of constructionist pottery, education, analysis, design and repair as it pertains the ceramic arts community.

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  1. So how did calculated COE work out in the end?
  2. I have used green patch pretty successfully to fill most dings and dents. Just do not let it come in contact with elements if doing any minor fixes in the interior. There are more color matched repair products available.
  3. If that is supposed to be a gloss glaze it definitely looks underfired. Does it ever have a gloss finish? See below.
  4. @MFP Bmix is pretty forgiving so if it cracks then I would say change up your drying method. Even my toughest porcelain (Laguna Frost) drys fairly quickly without cracking if my throwing techniques are good. I usually throw the mug on the wheel head, cut it off and set it on a cheap Cfold towel often on a wood bat or ware board. From there I use a technique Jennifer McCurdy showed me where the plastic is gathered, inserted in the center of the mug and just allowed to drape over the sides all around. The cfold towel (paper towel) wicks water away from the bottom nicely and the loose plastic allows it to dry leather hard in a day or so. Most of my cracks used to be at the bottom so we found a way to make sure the bottom is very compressed. Has worked for our students pretty well for some time as well. here is a quick video of what we do that has eliminated many of the cracks in the bottom.
  5. I like the tool, who doesn’t? As far as the rib, I am just lazy and started doing it years ago. Not the best but works. Here is an old (somewhat awful) student video that does show the use of the rib. We had student requests when they looked in my mugs they said, hey how did you square this inside corner? So we made a simple video of - a - way to do it. As far as better thrower, don’t get your hopes up here.
  6. Open wide, say ahhhh? sorry, couldn’t resist.
  7. Yep, that’s what I do when something is narrow or not at least twice the kidney rib diameter. Maybe 3” diameter is my limit.
  8. Anything you can do to slow the program rates down will help so the segments make sense to me. For me I would set an alarm for when the kiln finished and take some data every 15 minutes till 1600 degrees or so of a non powered cool down to know what they basically are for that kiln. From there you should be able to develop just about any schedule you like staying conservative within those rates. I don’t have a great way to cool this evenly and quickly as the potential for sudden drafts and local rapid cooling makes me wary. So pulling the port plugs early in my view has some risk. I am not a fan of disabling the error function either but have observed others do it hoping to make it through a firing. Our best no thought studio solution is to not fire in the insulated kilns if possible for powered cool. We have one L&L rectangular kiln, 3” brick, no insulation which cools much more quickly on its own and five Cone Arts which are insulated. When we can fill the L&L it generally is Easiest to run the power cool without worrying about rates much. As to having insulated kilns we enjoy the saving in energy. I think measuring your natural cooling rate and knowing what it is is still my best suggestion. A bit of a pain but once known may be very useful.
  9. I use the corner of an old wooden kidney rib. Curved Inside for bottom inside the pot and pointed outside to trim off anything not round at the base on the outside.
  10. @CAR More than you ever wanted to think about cool down! The shutoff feature can be turned on or off except it has no effect on down ramps. On down ramps the kiln will begin the hold when any zone falls to the set point temperature. The excerpts attached are from Bartlett and available for down load at: https://www.bartinst.com/manuals/kiln at the bottom of the page there is an operating manual AND a technical manual. Just a word of caution write down your present technical parameters before making changes so you can return your controller to its previous setup. interesting in that some folks leave the fan on to alleviate this condition somewhat and this time you turned off the fan. Their kilns don’t reach cool down set point fast enough on their own so they leave the fan on. The fan generally does not provide a whole bunch of cooling speed to this BTW, if counterflow it usually removes a very tiny bit of air. Slow cool is a bit misleading in that we are really engaging in a powered cool down to control the cooling in a certain range of temperatures so crystal growth can take place. To give an idea how things cool I have attached a measured cool down of one of our Alpine kilns, a very leaky old gas fired 16 cu ft. Notice how quickly the rate of cooling drops as the temperature difference from inside to out decreases. If we added insulation to this kiln the rate of cooling would decrease even more dramatically. Recording this manually may be the best way to know what speed it goes on it’s own. By 1800 degrees the rate is less than 300 degrees per hour for this kiln. The data you see here was developed so we could develop an equation that would predict the cooldown so we could add this function into a monitor allowing folks to power cool the gas kiln and not have to sit and watch endlessly while it cools. A bit overkill but really nice to have. The equation we settled on is below as well. Since then we settled on the final programming allowing the user to enter early warning setpoints and receive a text a few minutes before they needed to return to the kiln to Power up for their hold. To answer your bisque fire question it will tell you something but is significantly short of cone six temperature where the cooldown rates are the highest. Probably a cool subject but actually more than you probably ever wanted to know.
  11. Double wall pipe is fine for gas service if and only if this is just a natural draft hood that will draw dilution air along with the kiln fumes. Additionally For reduction the hood must be mounted high enough so the flames never impinge on the metal. So yes, if using double wall pipe the hood must be designed to not exceed 500 degrees of which btu and stack height will be the primary drivers of the equation. Even when we design these we always test at top temperature with an infrared device to make sure we got our assumptions correct.
  12. I have seen this error on insulated kilns where the kiln will cool slower than the ramp programmed and therefore the controller believes the kiln has a stuck relay. Bailey used Frank Tuckers (Cone Art) design which features his lid lifter and the insulation which I have seen take longer to cool than many program down ramps. Yes, insulated kilns do in fact out perform non insulated kilns thermodynamically just like insulated glass outperforms old single pane in a house. 3” brick cools quicker than 2” brick plus 1” of insulation pretty much every time. Packing the kiln tightly, along with the insulation tends to exacerbate this problem. Kilns that are super insulated have other provisions that allow the user to vent some of the heat so slow cools can reach their hold points in a reasonable time and not cause this error. The controller has to default to an error at some point if it appears a relay is stuck. I have excerpted two parts of the Bartlett manual. One section reflects that ANY down ramp will begin its hold based on the coolest zone so the middle being hotter than the others can be a problem if significantly hotter than the other zones and you begin your down ramp hold but it is quite a bit higher than your hold temperature. The second excerpt allows you to turn off the error function for special firings issues. One thought which takes some effort and observation You might have to set a completion alarm then monitor and time how quickly this kiln cools to get some ramp rates that match the kiln more closely for your down ramp programming for this kiln.
  13. It’s not the best as if it’s gas fired part of the combustion byproduct is water and there is that carbon monoxide thing. In an electric, I guess it’s ok but either way glazes often contain things you would not want in your pot roast.
  14. I think it depends on your design and what is acceptable by code. Codes are created to make things safer for the mass common application. So flexible gas appliance connections are generally limited to six feet in length, now mostly stainless steel and single flare connections. They allow the appliance to be moved in and out and maintain their integrity for many years. This takes into account the low operating pressure (less than 1 PSI), wall thickness of the flexible tubing, and pressure drop that will occur in this flexible connection. If your kiln is permanent or semi permanent, hard pipe to a fixed location near your tank with the final connection between tank and pipe being flexible. Some states accept copper, virtually all accept black steel pipe and there are some that require stainless steel piping or tubing. For above ground vapor service in a permanent or semi permanent appliance location black steel pipe likely is fine from the kiln rigidly mounted and adequately supported to a point near where your tanks will be. Likely Worst case your state would require seamless tubing. Black pipe is nice and certainly has sufficient wall thickness but in PSI pressure ranges must be adequately joined and pressure tested to ensure no leaks. This is a tough subject actually, in the State of Illinois high pressure natural gas vapor service must be fully welded construction and tested. We can however use newer cross linked (rated plastic) service gas line underground in many circumstances as this is designed to be impervious to corrosion and often carries a tracer wire in it so electronic location is possible in the future. Same problem with fiber optic cables btw, no way to find them after they have been buried for years. Perhaps the easiest and safest way for you to do this would be to have a licensed plumber do the hard pipe from kiln to a location where your tanks may be in accordance with local codes. Have him pressure test after completion ( often a one day leak down test), then attachment to the tank would be an approved propane tank flexible o ring connection just like a gas grill. In the meanwhile the regulator and isolation valve would be hard piped into this line near the kiln, per code, to comply with available service (shut off) requirements of the appliance under code and to ensure the burners have 11” of pressure to them (I think that was their max. rating). So at the kiln a service shutoff (usually within six feet), regulator, then operating valve would likely be the configuration. Generally a pressure gauge downstream of the operating valve is standard so the operator can see the adjustments. I suspect most folks just run flexible hose from their tank and declare their kiln as non permanent. My further suspicion is this will be permanent and therefore not per code and technically not able to use the flexible hose start to finish. Now put wheels on the kiln and you likely have a whole other argument. Actually pretty complicated stuff and we haven’t even talked about running piping for liquid propane delivery when tank vaporization rates cannot keep up. (Frosty tank) Seems like hire a reputable licensed plumber is likely the best answer!
  15. At that speed it will take three hours to get to 200 degrees which for glazes only probably is plenty. An additional hold for four hours seems excessive especially glazes only. For sure ought to be dry
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