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First, why vinegar in the throwing water? Usually when we see black on the wheel head it is simply a tiny bit of the aluminum abrading from the clay. Could just be the abrasion of the bat against the wheel. Does wiping it down not remove it?

I bought a brand new Shimpo Whisper VL in the middle of January. I have been using a bat system and have only really thrown porcelain on the wheel. I don’t clean the splash pan very often but I only use a bat when I throw. Yesterday while I was cleaning the wheel I noticed black stuff coming off the wheel and it feels abrasive. I don’t know what it is or how to get rid of it. I use porcelain so there is some vinegar in the throwing water but I didn’t think that would hurt anything and I usually have a bat on top so I don’t know why/what or how to get rid of it. Thanks

If we’re taking bets, I call iron in the water being the culprit. It’s the one constant variable across all OP’s tests so far. Very interested to see how the distilled water variation turns out.

@AndreaK I think you’re probably relatively local to me, so I assume we’re talking plainsman clay at least. Does the studio you’re looking at do commercial or homebrew glazes, and what kind of work are you thinking you’d like to make?

Ferric chloride isn’t necessary by any means. I haven’t done a whole lot of pit firing, but I did a couple back in college. You can get some lovely variations with terra sig on its own, especially if you’ve got a light and a dark colour to create contrast with.

Probably. Part of the fun of working with found materials is the variability. Sometimes close enough is all that’s needed.

When we produce a ceramic material that allows "light" to pass through that material we are working with a "glass" even though us potters call the material a clay body or a glaze. Todays "Ceramic-Tech-Today" article: Colored glass: From alchemy to empirical chemical design https://ceramics.org/ceramic-tech-today/education/colored-glass-from-alchemy-to-empirical-chemical-design/ has some useful information and background that might help determining why the bone-china pots show a color when seen in a light source. Remember that the source of the "light" is also an important variable. LT

It's my zero3 fritware clay, kiln is just a 40 litre rust bucket. I would go with the cone program as it may dynamically alter the firing depending on how it keeps up with the rate of climb. Do skutt controllers do that?

How fast did you fire it? Is it still sitting on the garage floor, if the floor is concrete you could have a uneven firing. The concrete is cold and will keep the bottom of the kiln colder. I understand that this is a small kiln, small kilns have to be set up correctly. I had one in front of a window but had to keep the window closed. It could really slow the firing and cool it down to fast. Small kilns already have a problem with fast cooling. Denice

After looking at the manual posted in the other thread this controller seems a bit weird. T1 is the time taken to get to the NEXT temperature not the C1 temperature. That seems backwards to any controller I have programmed. C1 0020c, T1 0030m C2 0100c, T2 0030m C3 0100c, T3 0600m C4 1140c T4 0100m C5 1240c T5 0000m C6 0020c That should go from room temp to 100c in 30min and hold at 100c for 30min. Then it takes 10 hours to get to 1140c (you could speed that part up) and then up to 1240c in 100m (60c/h)

Are you bisque firing first?

An image of the piece, err, pieces could help - character of the break, how thick/thin the ware, etc. What clay(s) are you using? About how long does it take to achieve 1240C? From peak, how long does it take to cool to room temperature?

It's not about temperature, it's about heatwork, which is what cones measure. Setting it at 950C doesn't necessarily mean cone 08. It depends on the rate of climb of the final 100C degrees. If it's not hitting the cone, then it could be due to the rate of the final ramp, or simply that the system needs to be calibrated. You can do a thermocouple offset which will affect all temperatures, or a cone offset to change the final temp of a specific cone. Using the pre-programmed firing schedule (I'd use Medium speed) will give you a better idea of how accurately the system is firing compared to a custom schedule.

Thanks for your reply. Not having any problems with the pots but rather feel that its not achieving the desired bisque of 950'C - trying to keep everything consistent so I know how the glazes will behave when applying and during the firing

Thanks for your message. I am going to try the preloaded cone 08 bisque firing next.

Thanks Neil, this was my next thing to try

That is a pretty low bisque...250°c/hr ìs very aggressive, what type of kiln is it? What clay body? I thought cone017 was for enamel work..

This is my first time firing my mug in a kiln (I use Mid fire clay) I used these segment: C1 (160c) 60min C2 (500c) skip C3 ( 1240c) 20 min C4 (room temperature) Each time I use my kiln my mug breaks Do you have any advice?

I tried firing it today at 1240c but my mug broke I put the Kiln in my garage and it is on a ceramic floor

I make terra sig regularly with my local clay and follow something similar to @Magnolia Mud Research’s post. I don’t go to great lengths to extract any remaining “finest particles” from the dregs. I played with that a bit but found it was counterproductive. Letting it slake a few hours then mixing it really well gets the all good stuff in suspension. I’m sure this is derived from Vince Pitelka or maybe Pete Pinnell, but it’s what I go with: 1 quart water to 1 pound of clay. 2.5 grams deflocculant per pound of clay. My deflocculant is half soda ash/half sodium silicate.

I came to the conclusion that low fire materials just didn't work for me for items needing to hold liquid..especially over time, and if given/sold to other people. It meant spending a fair amount of time (and a definate loss of money) learning how to make the chemistry/glaze ingredients/porosity etc. all working in conjunction. Mid-fire (or high) fire claybodies and glazes were way more likely to result in the desired maturity & glaze fit. I used low fire more for decorative ware that is not subject to freezing temps, no oven/microwave/grill, no liquids or wet food (like a tray for pretzels is OK) , or not something that will get lots of handling (depending on the object and it's purpose). ALso did a fair amount of reading, taking a course/class (today it is videos), to learn the basics before spending on trail & error.

I'm voting iron as well. I think that also accounts for the pinkish tint in low fire bisque pieces. If we were able to have a slab that thick of our clear glazes we would also see it to varying degrees. Window glass is also green for that reason. It look pretty darn clear when we look through it, but if you put some paint on it you'll see just how much color it really has. They make super clear glass, of course, but it's expensive. If I remember correctly they call it Water White glass. Standard plate glass and such is quite green. I worked for a glass shop for a few years after grad school, and we would occasionally have to replace opaque colored glass panels on buildings that were no longer available from the original supplier, so we just had to paint the backsides. Getting an accurate color match was nearly impossible due to the tinting effect of the green. You couldn't just have the paint color matched to the old panel.

I have a sieve that fits a 5 gal bucket, I bought it about 40 years ago. A few years ago the screen started break along the edges, so I went to the supply store and the same screen had a flimsy plastic body on it. My old screen has a heavy plastic body, my husband sealed the screen in with a waterproof adhesive. It isn't very pretty but it works and I have a really small sieve for test glazes. Denice

It's rate to just above cone 6, which means it'll only get to cone 6 maybe 50 times max before the elements need to be changed. Probably a lot less than that given the quality of the elements they are likely using. So to get any sort of real life from the elements you'll probably want to limit this to cone 2 at the most. Really we consider cone 6 kilns to be best suited for low fire work. I would definitely check to see if you can even get replacement elements for it. It appears to be on angle iron legs, but they're not very tall. Most kilns have 8" legs, so this kiln is on the short side and it should definitely need to be placed on something fireproof. If it were mine, I wold put it higher up on some bricks to give more air flow under it, with a fireproof floor below.

@neilestrick Could you comment on a couple of points. - 1) The kiln is rated at a maximum temperature of 1,240°C/2,264°F. What is a sensible firing temperature to give reasonable element lifetimes? 2) Fire safety. The manual states: Please only put this kiln on a heat-resistant worktop such as a metal stand, stones or ceramic tiles. Please note that the worktop should be very stable and be able to hold up to 30 kg of weight in total, for your safety. A photo in this advert shows the use of short legs/bricks. https://www.amazon.co.uk/Top-Loaded-programmable-Pottery-Projects-Beginners/dp/B0BZ53RXKM I assume that anything like this should be on a very fireproof/heat-resistant surface. PS @Moza Where are you intending to place the kiln while firing?