Bill Kielb
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Posts posted by Bill Kielb
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14 minutes ago, Potterbabe said:
i have a cone 10 glaze firing program established with this kiln on natural gas will there be any variation on propane?
I agree with Neil, however reduction and your visuals likely will change a bit. That nice blue flame is not something you will see so much with propane. Propane literally has double the btu output per cubic foot used, but proper orifices will compensate for this. You should be firing on temperature and rate so manually controlling will compensate for slight faster or slower. For reduction, your visuals will change a bit but not something you will not grow accustom to.
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Still a nice look. It’s really difficult to get true mirror like gold. The PVD coating above was actually a pleasant surprise to me.
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Dishwashers can be fairly aggressive on non durable glazes. This a soda fired piece so not something designed and tested durable. Looks like the dishwasher dissolved some of the surface of the glaze. It’s soda fired so hard to predict and no guarantee it will end up durable.
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Looks better than expected. I wonder if you can buff it, not necessarily to a mirror but glossy smooth?
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10 hours ago, PeterH said:
The rather large difference maybe related to the speed of response required?
No, I think my math. Assuming 8”round prox. 20.32 cm so area should by 3.14x((20.33/2)^2 ) = Prox 324 sq cm. So 22W (from above)/ 324= ..068W per sq cm. A bit more than your floor heater ought to melt ice off your mirror as opposed to heating a floor to comfort temps.. I think you are in range and my quick calcs are wrong above.
All done flipping back and forth on this iPad, but seems right. Someone should triple check all the calcs if the OP does want to do this in some fashion, I think we can sneak up on a real potential load.
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On 8/3/2023 at 4:22 AM, PeterH said:
Do you have any guestimate of the weight of water that might need to be unfrozen? (It takes about 0.1 Kwh to melt 1Kg of ice once it's at 0C.)
The density of snow varies significantly. I kind of really liked the heated mirrors above for approximate established data. I think we really need more of a description as much as practical as the mounting and what it is mounted to could significantly affect the required energy as well. Gotta start somewhere so maybe size, mounting, materials ….. Maybe a display case in the end is practical.
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38 minutes ago, Ahmad.khd said:
and I was wondering, what if I reduce the length to 10 meters instead? could you tell me the specs of the wire in that case?
I think we can tell you more but you will need to tell us how big will this be ……. Tell us as much as practical. To be effective, I believe we are just going to need the potential load in watts which is affected by size and enclosure or lack there of.
Sorry, the above is the best thoughts that come to mind to address the potential load. Maybe others will have more insight here. I would suggest describing what you envision as completely as practical though.
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23 hours ago, CeramicHugs said:
So, what are they using?
Still not sure ….. PVD coating that sticks to ceramic? (See below) it’s definitely not common and lusters have served this function with reasonable durability for potters. Most folks try and keep the lusters away from high wear and direct contact with food as well just to be extra cautious.
I see this finish on many other materials such as steel and plastic more so than ceramic. I am not aware of a glaze that can produce the finish nor a traditional spray applied coating either. Spray applied coatings generally lack durability and are often not high temperature tolerant.
If you figure it out, maybe you have something folks have been asking for for years. PVD appears a bit expensive unless it scales well to produce thousands of items.
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Knowing that, I would suggest a carbon fiber heating element or flexible element often used in heated clothing. 80 meters of Nichrome is a very long distance so not sure what area you plan to heat or how you intend to distribute the heat from a single wire. My first instinct is to enclose or protect from snow, maybe move energy with air, but that may not fit your use. Maybe a full description here will sparks some ideas from others.
Just to add a bit to this we are talking about raising some area from -15c to above 0c with only still air (undisturbed layer of air near the fabric) as an insulator. The slightest breeze makes that layer go away. This can become a very large loss of heating in a hurry. Maybe insurmountable wattage actually, when we look at available batteries and storage.
I think the more accurately you can describe here it likely will improve your chances of suggestions by others.
@Ahmad.khd Just looking at this further, car mirror heaters might give us an idea of the energy required. If my quick math is right - temperature dependent - it looks like on the order of 1-2 watts per square centimeter. Likely not trivial depending on how large an area you are trying to defrost. Cold climate Heat pump technology could produce this at 1/2 to 1/4 the electrical energy vs resistance heat.
Assuming the above is correct my thoughts go to dark minimal awning, maybe using the existing sun as practical and a ducted heat pump only when essential. Maybe even automotive heat pump.
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6 hours ago, Ahmad.khd said:
Hello,
I have an 80-meter nichrome wire and I want it to heat up to 40 degrees Celsius maximum (30 to 40 is ok). I want to connect it to a battery that is enough to make it hot for at least 10 hours.
The ambient's temperature is negative 15 degrees Celsius.
What is the diameter for this wire? what is the resistance?
What are the spec of that battery in this case?
My thought is first work out the total heat needed which goes to what are you trying to heat up and what are the losses. Once you know the losses in watts we can figure out how to replace those watts with available nichrome wire (Diameter and resistance using your 80 meter length) and available batteries. It’s actually a very significant problem in my mind where no simple answer comes to mind. Perhaps a bit more description of what you are trying to heat would be helpful here.
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7 hours ago, Gonepotty said:
I have tried using the pre programmed bisque firing and had similar issues with cones not bending.
Hmm, the machine should generally ought to do it better or at least more consistently than creating a custom program. So when you create your schedules do you follow the last 100c requirements in the Orton chart?
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21 hours ago, Gonepotty said:
It's a new kiln and only done 13 firings. (Skutt with touch screen controller).
Program is in celcius
Set 1 :80 degrees to 600
Set2: 100 degrees to 800
Set 3: 50 degrees to 1000 with 20min hold
Just curious, since it is a Skutt with the touchscreen controller, why not use the cone fire programs rather than working with holds and various rates? Also - to get a particular Orton cone to fall it’s customary to set the last segment rate to that shown in the chart. Begin that rate 100c before the cone temp. If you follow Orton, just curious if anyone has explained how that chart is intended to work?
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Not that it’s not possible for this to work, I would say with this level of cracking, highly unlikely. I am with min wondering about pouring dry.glaze in and out. I am not familiar with this technique from Mayco etc… or the expected look.
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2 hours ago, PeterH said:Have you tried pressing what looks like a rectangular button on at the top RHS of the blue plate (while the power is off) it might reset the ELT.
Usually cycle off after a test resets it. The interesting point though is to definitely cycle this test switch to make sure it’s not stuck and releases freely.
Pretty funny though it’s either “off” or simply turn it to “No”.
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Just a late add - Nabertherm does a nice job IMO of explaining a bit about the fresh air and exhaust port. In addition, they suggest when to open and at what temperature to close.
Manual https://nabertherm.com/sites/default/files/noindex/2023-07/M01.1089_English_2023-06.pdf
- Section 5.5.6 - section about how the vent works with reference to piping, slope and height.
- Section 5.7 - first firing with fresh open 100% of the time to 950 c to season the elements and burnout in a new kiln. Just a good thing to know for future use.
- 6.5.1.1 - some nice preset program firing charts with reference of suggestions of when to close the fresh air inlet. Their range 950c-1250 c depending on type of firing,
Anyway, it may seem confusing but this does give reference to a suggested temperature to close the fresh air vent, and these appear to be me to be relatively conservative numbers.
This may help a bit. Perhaps confusing now, but likely will have greater meaning as you fire more and more and gain greater knowledge.
sample schedule below with specific closure temperatures.
Finally - why are we doing this? Here is a nice article from this web site that could give you an idea of what we are burning out and about when this happens. https://ceramicartsnetwork.org/ceramics-monthly/ceramics-monthly-article/Bisque-Firing-101#
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53 minutes ago, Smorzando said:
I’m afraid it’s left me even more confused to be honest! I am working myself up into a bit of an anxious state about all this. Having never fired a kiln before it is all rather daunting and reading so much online where most advice seems to conflict,
Yes, lots of interesting advice. The basis for venting with respect to fumes is what I tried to convey. If I had one wish looking back, it would be that I wish I learned the underlying why parts first instead of looking for a magic number, temperature etc…. Very confusing I know. It’s a fun journey, no matter the path.
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Many of these kilns use the buoyant properties of hot air to remove fumes instead of a mechanical fan, often called stack effect. At the conclusion of a bisque firing it is generally assumed all significant off gassing has occurred. Bisque firings work because of peak temperature and sufficient time in the firing for all this to occur. Even glaze firings have glazes which contain clay, and oxides which need to off gas almost as if being initially bisque fired.
So suction is determined by the diameter of the pipe, final height of the vent termination above the kiln and the temperature difference of the air. Height being a very significant factor. So in general, at bisque temperatures most off gassing is done, so that sets a credible termination temperature and depending on the height of the installation the inlet and discharge ratio is set to maintain a very small amount of air through the kiln up the outlet pipe …… just enough to prevent fumes from infiltrating into the kiln room.
opening the discharge a bit more than the inlet will ensure the kiln stays negative with respect to the kiln room. How much required is often a very very small amount and very dependent on final height. Open too much or too long wastes energy and in the extreme case could affect how even the kiln fires. So trial and error often establishes this.
A reasonable way folks often figure this out is the smell of wax resist burnout. If one can smell the wax early on in the firing, the kiln atmosphere is leaking into the kiln room. So opening the vent (s) just enough or slightly more to ensure this smell is exhausted …. and establishing this ratio (of discharge opening to inlet) results in a reasonable expectation that all fumes are being removed. Closing these after bisque temperature reasonably ensures a minimal amount of energy is wasted. The challenge is often to get inlet and discharge ratio established during bisque and then close the inlet only after bisque temperature so any very minor leakage will be out of the kiln room. The stack effect will always try and pull air out of the kiln.
Sorry for the complexity, but logic often says bisque temperatures are the magic number. Most manufactures stress the kiln must be vented but the variability makes it hard for them to provide uniform settings for all.
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Your design is single stage high pressure so it already exceeds 1/2 psi. Most kiln orifices - operating and pilot are design in the 0-14” of water column range, so a second stage regulator is often placed at the kiln. If you use a low pressure safety on a high pressure system you risk valve failure. So Ward is right, most pilots are designed down around 3.5” and are regulated for consistency.
In short, as designed you need the high pressure model if you keep the design as is.
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Yes, this should be simple to diagnose for a kiln repair person. The 1/2 amp fuse only provides protection for the control board, its controlled loads and the transformer itself. So check ALL low voltage wiring to make sure no cuts and scrapes are touching anything. If you Unplug the orange, blue, white that will test the control board and its outputs. Unplugging (red, black).checks the low voltage output side of the controller (basically the relay load)
Your transformer appears to possibly have burn marks on its secondary wiring side ( might be the smell) could be the picture though or could be from production. This could be from production, or defective as a result of overloading it.
Secondary voltage — The nominal voltages measured - orange - Blue = 12VAC, orange - white = 24 vac, white - blue = 12 vac. This is a 24 vac center tapped transformer.
The red and black are the output of the controller and ought to be 12vdc (nominal) when cycling the relay on. Green appears to be unused.
All of these items can be checked for amperage draw by your tech to see which if any are drawing more than 1/2 amp.
This should be your transformer specs https://www.mouser.com/datasheet/2/410/FD5_24-781304.pdf the U shaped jumper appears to be internal from the factory on this transformer.
This should be your kiln wiring diagram https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/S0743-1.pdf
I would double check all low voltage wiring for a short to see if that overloaded the secondary of the transformer. You may need a new transformer if it cooked itself a bit.
My experience paragon designs in accordance with code, UL and CSA so their wire size ought to be fine. Not sure who or where the undersized thing came from, but that saying seems a bit suspect to me.
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So my thoughts above seem to align with Paul’s…… shutdown by high limit or ……. Programming. I have experience with various Geil kilns and depending on configuration, pilot safety can be a bit touchy..
My observation converting these kilns is you may need to increase the pilot orifice size when all is said and done to obtain a stabile pilot and stabile operation so the kiln does not shut down unexpectedly in pilot safety.
Notice the before and after photos below. Before = lazy soft flame along the pilot bar, After = robust better defined flame.
Additionally we built monitors for these so I should have decent relatable engineering with respect to potters atmosphere on the Geil probe as well as oxyprobe. They are very useful in hand firing and following a schedule. The values for each are a bit relative so if you get to a point of using the probe I may be able to help quantify what we found. Picture of the Geil relative reduction scale below as well on one of the monitors.
Oh last piece of advice, get the operating pressure correct. This will most likely operate propane 0-14 inches max so a two stage regulator from the propane tank and the orifices sized for inches of pressure.
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You should measure approx. 25.2 ohms at the terminal block that feeds the four series wired center elements per the wiring diagram. If they measure appropriately then trace the wiring back checking connections to be sure they are powered.
Please don’t forget to disconnect all power before checking things.
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Again, if the middle elements do not glow, they are hooked DIRECTLY to the sitter. No relays, no interval timer, no nuthin. If they do not glow, there is a break in the wire, connection or since they are series wired, one or more of those four elements. They connect straight to power from the sitter and run continuous from start to finish. If they don’t glow, as in the picture, they need to be investigated. Since the top ring and bottom ring do glow - for now - it appears the relays and timers must be working.
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Nice! It’s hard to tell from your picture, but the middle set of elements should be powered all the time the sitter is on. They appear off to me in the picture. so if they don’t glow at some point then somewhere there is an open circuit and it’s unlikely related to the timers / auto manual switch.
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Looks like #40 is more correct. Their new kilns are 240000 btu and …… my mistake #40 might be a bit large in the 6 burner so #50 gets you closer. Decent table here:http://www.davegardner.org/images/GasInfo/OrificeTable.pdf If you are lucky it is on the kiln tag.
Looks like you want to max out at 240,000 btu by todays standards which means #50 or slightly larger, closer to # 48. If you drill them yourself and don’t leave the conical approach in, they will not perform quite as well as if manufactured. If you have #40’s in there and decent blue flame then I would definitely work the damper. Small (very small) adjustments will have very dramatic effects once you get closer to reduction. You. Want to keep as much heat in as practical, just short of reducing. This changes as the fire progresses and as the operating pressure increases as well.
updrafts can be tricky (especially a small kiln) but folks have fired them for years so they can be mastered. It does take a reasonable amount of patience though. It would be great if you could watch someone fire successfully. When we do this usually folks observing see a few things that they never would have realized. Demonstrating the dramatic affect the damper has often enlightens may so maybe seeing is believing I guess.
zehat are you using as a damper?
Gold glaze
in Clay and Glaze Chemistry
Posted · Edited by Bill Kielb
Nice just some conductive paint and you are on your way! Looks like somewhat non functional stuff (I should probably say non food contact or something like that) though, but nice for its use.