Bill Kielb
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Posts posted by Bill Kielb
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6 hours ago, Gonepotty said:
Thanks Bill. I previously tried top temp of 1230oC and it overfired quite a bit fully bending cone 9. Yes I use witness cones and this schedule gives me a perfect cone 8
Sorry did not read the whole thread above…. Of course you use cones! Just a thought, some glazes will pinhole and not heal well when fired hot. Counterintuitive, they do liquify more but don’t necessarily spread out and heal as one might think. Drop and hold is often an effective way to get these types of compositions to heal.
I also assume you are firing cone 8 because it matches your clay and glaze maturity requirements. If not, firing too hot can have its draw backs. -
3 hours ago, Gonepotty said:
1220oc with a 20min hold
just an observation
The 20 minute hold likely gets you to cone 7, not sure if that is what you are trying for. Do you use cones? -
10 hours ago, MochiFriend said:
PM2.5 levels did not go above 1 both in the kiln room and the house
@MochiFriend If this is an older monitor I would definitely check the pm2.5 module. They generally allow gentle cleaning of the optical detector and pathway. It’s really unlikely to have such low readings, especially when outdoor air is usually in solid single or double digit range. 2.5 micron stuff is really small to the point where a reading of approximately 300 would show as very fine dust in a beam of sunlight or laser pointer. Generally Everyone has to dust, even folks with 1 micron hepa air purifiers. So a count of zero or one seems relatively unlikely. Still you have VOC’s so the trend and delta readings super helpful to illustrate the point: it’s hard to completely ventilate a kiln indoors, and to be as effective as practical it’s often really hard for folks to do without some solid formal experience.
While much advice is well intentioned, it ends up a bit more non intuitive than expected. Picture below of me verifying that no matter how gently one scoops glaze chems out, hundreds if not thousands of very very small particles get displaced and migrate tens of feet or more, nearly instantly. The laser is a nice visual example much like the beam of sunlight.
Finally a personal thanks for sharing, this is a hard subject to address to the level in these threads and yet could help a significant number of potters have a better understanding of the dynamics present.
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3 hours ago, MochiFriend said:
A follow up! There's a smell in the kiln room (above + around the kiln), but no smell in the adjacent office room.
Readings:
500F:
TVOC
Baseline: 0 in all rooms
Living room: 0
Kiln room: 23 ug/m^3PM2.5
Baseline: 1 in all rooms
Living room: 1
Kiln room: 11200F
TVOC
Living room: 120
Kiln room: 320We are wondering if we should perhaps close the door to the small kiln room so that the only negative air intake is instead from the leaks around the house. I'm not sure if this would make it spread more or less given that the fan is not venting out all the fumes. (Our stove is electric and furnace intake is from around the house - not near the kiln room).
I think that given there is still the persistent smell in the kiln room even with the additional fan venting out -- I am considering to move the kiln to be right in the corner between the two windows (health is first..).
Sorry for the confusion, as long as you have enough volume in your house the makeup air from all the little cracks etc… likely is fine as you have run the dryer without issue and it sucks about 200cfm out of the room when operating.. So with the window closed maximum draw will occur from all other rooms which will limit the fumes from exfiltrating to the occupied spaces. If later, running the kiln vent, bath fan, stove vent etc… the volume of your house and normal leaks may not be enough and you will begin pulling from your furnace ….. providing your furnace is a natural draft furnace.
Anyway, two competing issues, pure ventilation and combustion appliance makeup air. Always safe to design in makeup air so combustion appliances behave well. So not a one sized fits all and best done by someone with experience and knows all the components of the home else out of safety you will likely see makeup air always suggested. Like most things if someone is viewing these problems as a stream of airflow, technically this is usually a very flawed view. Folks who do it everyday for real are very cognizant of the pressure difference.
Interesting results from the air monitor btw. I see a lot of general assumptions about vents, kilns and working near them, this may be a nice simple way to show folks All the fumes are likely never captured by down draft ventilation. Your pm 2.5 results seem low since outdoor air is generally above zero. Regardless a nice indicator of trend and your monitor does voc.
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As a suggested test I would take one piece that is very intact with no defects and fire to cone 5, not cone 05. Your clay and glaze are midfire, not low fire.
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I think I would be very pleased to know the segment rate and after observing the delta graphically (or numerically) over time I would have a decent sense of how fast can this kiln go with reasonable accuracy and it would also be a strong indicator of element condition at peak temperature for me. Maybe less complex would be best for me and at a glance indicator of trend most useful.
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7 hours ago, MochiFriend said:
I'm curious if you guys think that having the one window open is necessary for intake airflow. I understand that the two outflow vents require a source of intake air, however would the intake air come from around the house as the room is not a perfect vacuum?
When you run the dryer it exhausts 200 cfm, window open or not, so no, air will be drawn in from the many minor openings in the house. Opening the window even a very small amount will help ensure that you do not suck fumes back down the flue of a gas fired appliance though. Most old codes allow exhaust by volume …. if there is sufficient home volume to draw from. Most homes have leakage on the order of 5 air charges per hour or more.
I would suggest you put your pm2.5 in the adjacent room(s) to get a pretty good idea if you are succeeding in exhausting all the particles generated by the kiln from the kiln room. Maybe confirm by noting the reading in the room vs the reading in other rooms. If the fan is large enough exhaust then the other rooms will remain at or near their baseline and change proportional to the activity in the other rooms as well as the pm2.5 outdoors. If you are a smoker, the counts will be crazy high maybe up to 1000 µg/m3 or more especially when you first light up.outdoor air will generally be in the single digit range for pm2.5 but can rise very high due to fires for which air filtration became one of the only ways to lower this count indoors. Your local weather station likely posts AQI and maybe Pm2.5 daily. For my location today, at this point they have measured in the last hour AQI of 29 and pm2.5 of 8 µg/m3 See below accuweather prediction for my location.
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4 hours ago, jay_klay_studio said:
I could also just include the out# for each T&C in the tooltip when you hover on the graph. This would only give you a reading in the moment, though, and might be hard to draw conclusions on.
I think I would like it in the tool tip but not knowing what data are available may not be the best choice so I will review the Genesis tonight. This is a cool project, just wondering if a universal excel template might suffice. No matter - nice project.
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If everything is intact, your glaze should be very underfired, but if it has stayed put and intact then I would test one piece in a cone 5 glaze fire. The worry would be if the glaze has come off or developed cracks that will not heal in the glaze firing. So as you remove those, very careful handling is probably really important. Firing a second time from cone 05 is very different than refiring. Right now your clay and glaze are not fully baked, so very different than a second glaze firing.
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20 hours ago, jay_klay_studio said:
Here's a graph from my most recent firing (where it's clear that my kiln struggled to maintain ramp at peak but otherwise was pretty close
Much better! I would suggest to see percentage output from the controller if possible, by zone would be great, so at a glance I can tell if the kiln is under powered at some point or the controller PID needs some calibration and tweaking s practical.
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1 hour ago, PaulineNL said:
It’s Georgie’s PG630 Zinc Free Clear Gloss Glaze that fires to cone 6
So If you fire to cone 05, the clay will be bisque fired only, so porous and weak and the glaze will be severely underfired. The normal progression would be decorate with underglaze, then bisque fire. Then glaze with a glaze matching the cone of the clay and fire to cone 5/6 so the clay and glaze melt and mature as expected.
I think the confusion here is the clay is not really firing at typical terracotta temperatures, it’s just called that and is a midfire clay that matures at cone 5.
The good news is this may work just fine for a single fire to let’s say cone 5, just use a slow / medium bisque schedule but still fire to cone 5. Definitely something I would try and test. The clay should off gas and burnout as a normal bisque firing and then go on till maturity (cone 5). If your glaze tolerates the off gassing, then it will heal and be just fine when mature. Definitely worth a test IMO.
This is often referred to as once firing and many combinations do just fine which saves one whole firing. Going slower than a normal glaze firing (bisque firing speed) is precautionary to allow enough time for the organics to burn out before proceeding onward to cone 5.
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5 minutes ago, PaulineNL said:
Amaco Velvet underglaze says fire to cone 04-05. So I I think should be ok. I’m so new to all of this and there is so much to learn technically.
The underglaze is fine and will fire higher, specifically what clear glaze is on the piece? Velvet under glaze will basically go to cone 10 btw.
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What cone is your glaze? The clay is basically cone 5 red clay so the glaze needs to be cone 5 for them to mature together. If you bisque this clay itt will be a fragile sintered bisque which most likely would not work well with a cone 05 glaze. So what cone does the glaze mature at?
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Terracotta COLORED stoneware mature fires to cone 5. So I would glaze fire it to cone 5. I also would bisque to 04/05 but I think you. Have glazed it already. So maybe once fire to cone 5 using a slow / medium bisque schedule. Of course assuming you used a cone 5 glaze and not a lowfire cone 05 product. If you glazed with a cone 05 product and have not bisqued, I really don’t have a good idea other than remove the glaze someway and bisque fire to 05, then glaze with a cone 5 product.
It is not functional and fragility may not be an issue, so trying one of them to cone 05 bisque schedule might get an acceptable result.p for now.
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11 hours ago, Dave Earley said:
This summer I got two used furnace oil burners and added a second nozzle to each one.
Might help, my experience as an old guy - oil burners are pretty old technology so lots of reading if you just Google oil burners. Some decent plain English reading here IMO https://inspectapedia.com/heat/Oil-Burner-Nozzle-Selection-Guide.php#FiringRate. Picking a correct pressure important, used to be no less than 100 psi which has grown to 140 psi for finer droplet size, better aeration. 140000 btu per gallon is how I learned it (no2) and nozzle dispersion critical to cover the firebox without impingement. Anyway, pressure, size, cone angle all contribute significantly and mostly really good filtration to avoid clogged nozzles.
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If no need to be double sided - conventional masking tape? There are a variety of adhesives, fine line, etc, to choose from and they are available in different widths.
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New elements for 240 v service and a bit of wiring change will get you there appropriately. Find the wiring diagram for your kiln in the single phase model and build / rebuild accordingly. If a transformer is in the kiln for controller power, chęć / change the primary jumper to match 240v. For breaker / wire size check the manufactures 240v model requirements.
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1 hour ago, MochiFriend said:
Do you recommend attaching any kind of "capture device" on the end of the duct that is in the kiln room, eg. some kind of lightweight hood or umbrella-looking thing? Or just the end of the tube sitting there near the kiln is fine for the purposes of testing this out?
Any hood is great, higher inlet better than low is good but really if you get it in the room, the room is small and to keep the odor from exiting the room, near the kiln much better than you are doing now. Keep in mind, the kiln vent is capturing many, just not all.
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9 hours ago, Giovannaaa1109 said:
I got paranoid that I didn't hear anything else and stopped the kiln when in hit 75 degree F. I did put my hand inside and it did feel slightly warmer than the outside temperature. But I feel like when I fire I usually hear more clicking, but am clueless at this point.
I would suggest running a quick test fire to let’s say a few hundred degrees. So 1 segment program, go as fast as you can (9999) to let’s say 500 degrees. All the relays will turn on and stay on till near 500 degrees. Ought to take minutes to achieve and you should see all the elements glowing. You don’t fire enough to intuitively know if what you are hearing is normal or not, so a quick test at least should show everything is working - or not.
Do this without stuff in the kiln, especially wet stuff!
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16 minutes ago, MochiFriend said:
thank you!! this looks great!
Make sure you pick the right model and control. The picture shows three different applications. You likely want the 6” round with the outdoor louvers. Airlift air shutter series
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10 minutes ago, MochiFriend said:
2) also ran ducting from the fan out one of the two windows in the nearby room? (I have a cover that can cover the entirety of the window except for a hole for the vent). Below is a diagram illustrating this.
This will work, mounting the fan on the board to directly discharge, then run the duct in the crawl or wherever. With the fan mounted at the window all the rest of will be negative pressure, so no worries of small leaks. This is traditionally how we treat exhaust duct in general to guarantee no exhaust leaks out of the duct.
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1 hour ago, neilestrick said:
The one I have in my shop is fairly quiet, but I don't know the actual db output. If you had a couple feet of flex duct between the motor and the hole that may help to dampen the noise.
You might be interested in AC infinity. I have had them installed in several kiln rooms and model dependent they come with a temperature controller which varies the speed as required. Very quiet fans for the most part at what I think are reasonable cost. Google Ac Infinity.
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Skutt Envirovent still allows fumes
in Equipment Use and Repair
Posted · Edited by Bill Kielb
@MochiFriend
Just in case you end up in the garage, years ago we helped with a system (very low cost) that would allow studio users to fire in an enclosed dock. Not totally pertinent here but maybe helpful to look at the intent to intercept the various sources of air without overdrawing them but still ensuring the room was reasonably negative with respect to the studio. The carpet blower was an ideal economical high power blower that needed to be in place and operating during firing. Marcia Grant ( my Marcia) was nice enough to sketch this so it would be more understandable for the folks in the studio.
Anyway - a nice sketch with some well illustrated terminology for the various sources of air, might be useful for perspective for others here or for you if you move to the garage.