Bill Kielb
-
Posts
5,150 -
Joined
-
Last visited
Content Type
Profiles
Forums
Gallery
Posts posted by Bill Kielb
-
-
-
@Lbs With that meter you need to set the ohms on X1k connect the black and red meter leads to each other (hold them firmly connected) and using the zero adjust on the left side to zero the meter as precisely as you can. Top green scale, zero is to the right. This will now indicate that the shorted conductors are zero ohms and the meter is now calibrated. Uncross the leads and begin measuring the elements. Please make sure the kiln is unplugged (no power) before making any resistance measurements.
edit: the readings should be in the single / double digit range: ie say 1-30 ohms. If not change to the X10, re-zero as above and make your reading. It’s been many years since I used an analogue meter with an exponential scale so not sure if that is a multiplier or full scale indicator. Regardless calibrating to zero is the important part and translating the reading to something in the 1 to tens of ohms range will be the answer. The elements will not be 100 s of ohms. Calibrate to zero each time you change scale is the important part. Record your results, scale multiplier and post.
-
24 minutes ago, Sage Real said:
This makes a lot of sense thank you. I’ll definitely look for a copper red and test it out next.
In addition, copper red formulations are a nice visual test of how much reduction you have - usually at least medium to get a fairly even pronounced red and whether you are maintaining the atmosphere long enough as copper red will show green / grayish where oxidized. Pretty handy to place throughout the kiln to see how evenly the kiln / firing was. Nicely reduced copper red test tiles and a very nice spyhole flame pictured below for reference.
-
8 hours ago, RGsandra said:
Basically, on my kiln safety instructions says to don’t heat the kiln continuously for more than 8 hours.
I am not sure if I bought the right kiln for my work?Does this firing depends on the dimension of the pieces? Is 8 hours enough for a raw glaze firing?I am confused. I will appreciate any help
I would like to put into practice a single/raw glaze firing.I am with @Kelly in AK make, model and top temperature rating info for sure …. And to what cone you expect to fire. Clay and glazes generally don’t fire by how many hours. Lowfire clay ( cone 04 range) and wares that are relatively small can fire fairly fast without issue.
As far as single fire, your clay will likely determine if it needs a fairly long bisque to remove all organics, else standard glaze firing timeframe may be just fine.
- Kelly in AK and Rae Reich
-
2
-
some general ideas
If you fire with cones then you will minimize the chance things are severely over or under fired. So first question do you use cones and have you placed them in more than one location to get a sense of how evenly the kiln fires. What cone did this fire to? The other thing that comes to mind is application thickness and the color of the clay body and it’s similarity to the glaze application examples. Did you apply similar to the manufactures recommendations? And not to forget to mention …….. reduction. Good reduction is an acquired skill which usually takes some time to master. Reduction usually affects a handful of metals so glazes are usually formulated specifically for the reduction effects and then the firing is done verifying visually whether med / strong, early / late reduction was used for a desired result. So a reduction firing can muddy things up a bit but usually only affects specific characteristics of a glaze. In the beginning It’s rare just to fire to a schedule and succeed as intended at all these things simultaneously. Finally, test tiles - always use test tiles to confirm and dial in your desired look / firing.Many of these things require testing, isolating the result, and ………. experience. Seems like you are in the experience stage which unfortunately takes time. Tell us more about how you fire to cone, what is your schedule, maybe post a picture or two of the item(s) fired. How are you reducing and when do you reduce, why, etc…. Do you have successfully fired test tiles? Folks here can help troubleshoot and hopefully decrease that experience timeline or at least decrease the bad experience timeline.
-
5 hours ago, BobMagnuson said:
The tile on the left is Marcia's Matte. On the right is the same glaze with 20% silica added. It's hard to see in a photo, but the silica made the glaze less matte, but not glossy.
Much better photo! I’ve done this lots of times to illustrate the trend in Stull so I know this glaze will go full gloss with more silica. Not that’s how one would like to achieve the ideal gloss glaze. This is a common Stull observation and is not limited to magnesium mattes. Sue McLeod does her demo with a calcium matte I believe. The surface generally can go dramatically from dry matte to a gloss and becomes a technique to dial in a desired gloss level. I do agree the diffraction caused by the matte creates the appearance of opacity, but to Neil’s point, there are many glazes in my experience that are glossy and clear yet contain considerable Mgo so opacifier seems maybe not the best term.
Sues glaze https://suemcleodceramics.com/how-to-turn-a-matte-glaze-glossy-with-one-ingredient/
-
7 minutes ago, Min said:
MgO is in the role of a flux, glaze in question is a high alumina matte, adding silica doesn't negate the fluxing of the MgO
I agree, this was offered in support of Neils observation that matte and opacifier have very different meanings and I agreed with his observations as being consistent with my experience. So not intended to be a part of the Mgo flux debate other than from that perspective. Not dramatic is what confuses me with respect to matte / gloss. For this glaze and many others dialing in the amount of matte is simple by addition of silica (no special cooling required) which can be a handy tool to use in glaze composition.
-
15 minutes ago, BobMagnuson said:
since the effect was not dramatic,
I’m curious what the not dramatic reference means? I have seen these recipes do this so many times just to illustrate the effect that in general they follow the trend of the Stull map. Typically the recipes tested will go dry matte to full gloss once above 7:1 Si:Al to let’s say to 9:1. From a surface texture perspective, and gloss meter reading I believe that would be dramatic.
-
19 hours ago, BobMagnuson said:
but the added silica did indeed make the glaze glossier, though still somewhat matte. Notice how the scribbling on the original is a bit less black than the other two.
Marcia’s matte was an example of a Mgo glaze that will go matte to gloss with nothing other than the addition of silica. Actually the surface change should be quite dramatic and your pictures do show a significant difference in clarity and surface gloss. Actually, this glaze will go very glossy with more silica. It was an example that matte is not necessarily the same as an opacifier which occurred earlier in the thread. Interestingly your pictures seem to illustrate that point quite well.
-
1 hour ago, JTMD said:
OK, I know what an infinite switch does, it's how it's used in this kiln that's confusing.
Just a thought or two,
This is one of the only kilns that operate in this way in an attempt to semi automate the process. 99% of manual kilns are fired by simply folks learning to turn them up periodically to achieve their desired firing rate for that kiln. It actually is beneficial to learn the particular kiln and the why and when part of turning it up to achieve a desired rate. A pyrometer can be added as well which should allow most any type of firing. If you install infinite switches you simply install one per element set, no motors, timers, relays etc… the switch just cycles on and off on a duty cycle established by the setting on the knob. They work really well, have worked forever and lots of manual fired equipment out there still in service, meaning not a bad thing for a new potter to learn.Labview to me is overkill, most any any pid heating control will work and are thermocouple capable. SSR’s are great but ought to contain a mechanical safety to preserve safety in operation. As a gift do you want this to be a unique kiln to program or something conventional? SSR’s require decent cooling and thermal design, especially for passive cooling, not many folks I have found do this well up front.
Electrical safety is a thing, kilns are super simple devices but nuanced in the electrical safety aspect. My thought is making it unique and one off in programming without a solid knowledge in electrical safety and safe operation of a kiln has risks associated with it. I am still predisposed to a fully functional sitter and two infinite switches. If the sitter timer is mechanically interlocked to the sitter then a conventional timer without a start switch is probably available, economical and very popular. We never found out what that switch controls - might be worth opening the box and checking. Even if automated you will need something to ensure shutdown so repairing this one is likely necessary. ………. Just thinking …….
-
Lots of questions! Frustrating I know. You are right about the variables, they are infinite. Some folks here use Amaco glazes so I am sure they will weigh in. In the meanwhile pc 48 appears to fire gloss to semi gloss and yours is more dead matte which makes me wonder if it is under fired. Checking the Amaco website, they seem to fire these colors at cone 6, not cone 5 so there is a possible explanation for the matte. Additionally Amaco used to claim many of these glazes are float glazes so a fairly thick application was also needed to get things to float after they liquify. So more tests along the lines of firing to cone 6 and heavier application might be the ticket. Don’t forget to include waster or cookies for your test tiles unless you are very sure they will not run.
-
On 10/30/2023 at 4:49 PM, Julie S said:
. She doesn't see the value for students working with clay. She seems to be focused on the practical applications into the workplace.
Hmm, this may be tough as many forms of art have latent workplace benefits as well as the social benefits listed above. I guess it concerns me when an educator believes they know everything and no need to teach certain things or allow others to explore because they have little perceived value. Obviously ceramics in general can broaden knowledge in chemistry, geology, fire science, engineering, thermodynamics, etc….. Nothing like a finished product to help folks close the circle on knowledge.
It would be a shame to never let an architect build a model, or engineer to test a finished design, or perhaps an author only arranges words grammatically never to develop a plot or finish a story. I see this as similar to allowing one to sculpture but never fire their sculpture. (Very weird IMO)
It used to be you don’t know what you don’t know had meaning and making sure personal perception was not overly influenced by that. For educators it used to be a primary concern. Tough argument for you though, I think I would list the simple impact of increased knowledge in traditional sciences as a starter for practical reasons.
Donald Rumsfeld mentioned a basic engineering understanding. He was lambasted in the press for it, yet it was a fundamental tenant in much of science and engineering when I was taught. If your principal thinks the quote below is nonsense, then sadly you may not be able to convince her with any argument. She already knows…….
…there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns — the ones we don’t know we don’t know.”
– Donald Rumsfeld
-
3 hours ago, JTMD said:
My sitter just has a switch, that appears to be working OK and uses a seperate timer/switch
I see the timer push button switch in your video, likely the timer says turn past …… to actuate so you may want to turn it up to some minimum period and see if the push button will stay engaged. The interaction between the timer and sitter are traditionally mechanical to ensure positive shutoff and appears to be the case here looking at your kiln diagram. Your sitter is able to stay engaged on its own though so maybe an update to the drawing is in order and your comment that the relay engages when you press the start switch indicates the drawing might need an update. Pictures of the inside of this thing would reveal more.
42 minutes ago, JTMD said:(I design automated machines for a living)
I am with Neil though, two infinite switches and a functional sitter ( with a functional safety timer) make this kiln easier to operate and learn how to fire with. I designed DDC systems for buildings for years, the good thing, this should be in your wheelhouse. Infinite switches have been used for resistive loads for years and are economical and dependable. IMO restoring the old firing control scheme is likely not worth it.
-
On 10/30/2022 at 11:54 PM, Terri98 said:
I like that paper adds strength.
Maybe early strength and workability. When the fibers burn away it will likely be less dense so also likely the same or less fired strength.
21 hours ago, Terri98 said:What type of bacterial growth inhibitor might I use?
Have not seen it mentioned above but peroxide can be useful, a bit less harsh than chlorine and ends up as plain old water.
-
Generally electric kilns are rated and limited by the amount of electric power available and element life at their rated cone. With gas it’s really easy to supply lots of heating so generally easy to supply enough power to get to cone 10.
So in general the fire brick is fine, just a rating geared toward the kilns electrical capacity to produce enough heat. Having said that these conversions are generally fine, but not the most efficient or sturdiest or the easiest firing construct of a gas kiln. But they are economical, educational and generally can service many successful firings.
-
I will just add, it may be possible to burnout any remaining stains with a careful firing to 800 degrees or so. Obviously lots of risks to the ware with all methods and non destructive or surrogate testing some way almost essential so you don’t ruin the piece.
-
On 10/12/2023 at 1:57 PM, Vik said:
recommendations on the best detergents to effectively break down clay
My favorite clay detergent - Dihydrogen monoxide, best solvent I know of. Clay dissolves in it readily! Pre- rinse bucket O water, maybe rinse several times with rinse water allowed to settle before disposal. The problem with clay is the particle size are super small and fairly sticky so settling is realistically probably more doable than filtering. Detergents - not so much, water is extremely effective. Settling and proper disposal probably essential though.
-
3 hours ago, Julie_R said:
Any classes or workshops are only available in the major cities so not an option for me.
You may want to take a look at sites like: https://suemcleodceramics.com/. Lots of free stuff to read as well as online work shops. More free and paid resources https://digitalfire.com/glossary/tony+hansen, https://glazy.org/kilnschedules, https://ceramicmaterialsworkshop.com/
-
1 hour ago, Julie_R said:
Could it be that the glaze just doesnt fit my clay or is it just that my kiln cools too quickly when i shut it off?
My gut feeling is that the glaze doesnt handle that rapid cool as happens with these types of kilns.
Glazes almost always craze because they don’t fit the clay. Especially delayed crazing. I would say most likely that glaze does not fit the clay.
-
Just to suggest to try ending at the rate published in the Orton chart if you are using Orton cones without a hold unless you want additional heatwork to move to the next cone. So cone for cone 04 go 60 deg. Per hour in the last 100c.
cone 04 from chart : 1063c
Last hundred starts at 963c
last segment = 60 per hour starting at 963 and ending at 1063.
The final 100c of the firing is generally where things mature to cone and Orton has tested their cones to operate this way.
Just following the chart may improve your results significantly.
Edit: I should add here I would use the center rate or 60c per hour. Many kilns fail or eventually fail to achieve much higher, for which unless you are timing and calculating the rate, really messes with the correct endpoint. It can lead to what appear to be random results especially between bisque and glaze firings. In North America we have a popular automatic controller that actually detects if things are going too slow and will display as an error. So unless you are checking time and temperature for the last hour to hour and one half, it’s hard to know what speed it is achieving really. The 60 c column seems to be a more dependable ending speed most kilns can achieve with reasonable elements.
-
1 hour ago, Phyllis C said:
Do wooden cabinets need to be any further than 18" from the kiln?
The answer can be no, especially if the kiln manufacture specifically defines the distance from combustibles as a minimum of 18”. One of the unknowns here is how hot will the space adjacent to the kiln be allowed to rise to? The radiation from the kiln will also warm the wood considerably. Fire engineering says wood can ignite in the 450 - 500 f range so I think realistically having combustibles close to a kiln is not best practice and the farther the better. But note, if this space is setup so as to Always remove all the kiln heat, then 18” becomes less of a risk.
-
IMO I would fire them unless you are convinced you have a way to remove the stains without simply driving them deeper into the shelf. It should be mostly carbon so hopefully burns away to a clean finish. Whatever remains if any should be very inert moving forward. I would run a regular medium speed bisque - 10-12 hours. It likely will disappear sooner but a full bisque run ought to pretty much burn out just about anything of significance.
-
-
Your problems are not unique. Here is a post I placed in a previous thread to show what can happen when folks don’t follow the requirements. The whole thread is worth the read as we see this time and time again from owners to electricians and even an inspector on occasion. What I have learned: Get the right size breaker, check all connections carefully, not just a once over.
Paragon A88B, serial no. L79064
in Equipment Use and Repair
Posted
I like your thinking but in-situ sounds much more acceptable than live circuit measurement. To have a meter that does both is helpful but for folks without experience in work on live circuits it has increased risk.