Hulk

I think that Tony Hansen's demonstration of the fallibility of ChatGPT is worth posting.
ChatGPT is completely wrong about the cause of glaze crazing!
https://digitalfire.com/picture/3159
... a fine example of ignoring the elephant in the room.
... a fine example of ignoring the elephant in the room by ChatGPT
PS It reminded me of a very old software engineering joke (1970s?).
A man was been taken on a cross-country flight in a helicopter. During the flight the ground became completely covered in dense fog, and the pilot became lost. The eventually came across the top of a office tower sticking above the fog, and they hovered nearby. The man attracted the attention of somebody in the office and held up a placard saying "where are we?", and received the answer "in a helicopter hovering 60ft above the ground".

The pilot said "OK I know exactly where we are, and set off towards their destination.
Later he explained "the answer you got was technically correct and not the slightest help, so obviously we were at the Microsoft help centre whose location I know".
Maybe ChatGPT is another help centre.

There are several attachments.
Some wheel heads are keyed on.
The driveshaft on mine has a taper that fits into the wheel head, which is held captive by a perpendicular pin.
...the stratagems for loosening depend on the attachment...

The first step in identifying what type of wild clay you have collected is color. The sample(s) below indicate the presence of iron (pyrite) simply by the orange/deep orange color created when iron oxidizes in nature. This is an odd sample because the piece on the left has visible sedimentation lines, that vary between a 1/16 and an 1/8th of an inch. In addition, the left sample has a solid brown color on top and the bottom; which is rather slimy to the touch. The thin lines obviously indicate a sedimentary deposit, and the slimy coating, which differs in color is silt. In further evidence of being silt; it washes away rather quickly under tap water; while the remaining clay is undisturbed. There are also gray/white areas on the top of the large sample on the right; which is commonly referred to grey gumbo clay in this area. Yes, it is clay; but its composition and structure makes it unsuitable for pottery. In this case however, the percentage is low; so whatever is left after washing, will remain. I will add 2-3% more silica to compensate for the instability of the gumbo clay.
What else do I know about this clay before I begin processing? I collected it in a heavily wooded drainage area; so I know organics are present. Although not plainly visible; there are visible black lines between the sedimentary layers, further evidence of organics. I also collected it wet, and after just two days; the pungent aroma of bacteria is already present. Yet, I also need to determine if the black color is only from organics. I also know that there are large coal seams nearby. In direct sunlight, I can see that the overall hue is darker than a normal iron pyrite color. From experience, this dark hue is most likely from lignite coal particles, and not organics. After I process it a bit; I will run a Split LOI test: if the lower test firing results in higher LOI numbers, then I know it is all from organics. If the higher test firing results in higher LOI numbers, then I know it is lignite coal particles. You only want to clean out sticks, twigs, rocks, and sand before you run a Split LOI test.
The large sample on the right is also revealing. It was taken just below the sedimentary sample on the left and bottom. This sample has no real distinct sedimentary lines, and the color is nearly uniform. Judging from the color; iron content is in the 4-6% range. How do I know that? On the left lower corner of the sample on the right side, is a 1/2” spot of deep orange/red color. That spot is nearly pure iron pyrite clay; which runs in the 8+% range. I know because of the color, and similar samples ran at labs. Natural iron pyrite clay will be lighter as the iron content declines, and darker orange/red as iron levels increase. My educated guess, that overall iron content will come in at the 5% range. I will take a knife, and cut a 3” square by 1/2 thick sample and throw it into a test kiln unprocessed to check fired color. It is advisable to use a waster slab, just in case; but you need to check if you even like the fired color before processing very much. I have several 1/2” thick samples which I broke in half just using my hands. The higher the iron and alumina content in a sample, the more pressure it takes to snap it in half. In this case, it took a bit of pressure to snap; so I an estimating 5% iron and 24% alumina. Yet understand that is based on snapping many samples, and many of those sample being lab tested for mineral content.
There is one more oddity in the right sample; did you see it? Directly across from that 1/2” dark orange spot, is a nearly black line. That is a solid line of coal; and that also means that the dark overall hue, and the dark sedimentary lines are most likely lignite coal, and not organics. Your sample will tell you a lot before you even process; you just need to learn what it is saying. Lignite coal particles means inorganic sulfides: which translates to blistering, bloating, or even black coring if not fired correctly. So now my clay sample just told me how to fire it. I will program a rate climb of 108F an hour from 1250F to 1800F to ensure all inorganic sulfides have been burnt off. Usually, a slow bisq firing program will accomplish the same thing. Take a real close look at your samples; they will tell you many things.
Tom
 
 

Ok, the question’s been out here a while, but I just remembered an epic screwup that makes me laugh and had to share. Not the worst , but probably the funniest. I was loading my kiln, it’s outdoors and dark, so I turned on the flashlight on my phone and propped it up on the bagwall. Finished loading, got the door bricked up, lit the burners and reached for my phone to take a picture. Where’s my phone? Oh noooo!!!

Hi Fiona,
Welcome to the Forum!
For colours, there may be some choices that are less expensive?
If making up your own slip from clays*, red, brown/buff and white are common colors.
Underglazes provide a somewhat inexpensive way to get a lot of color; they don't go on the same way slips do, but they do have their uses...
Stains may provide a way to add a few colors to your slip palette.
The per pound prices I'm seeing are $12-18 (US dollars).
At ceramic temperatures, metals persist and provide coloring.
Blue/Cobalt is expensive (but it's come down a lot).
Green/Copper is more reasonable.
Maybe start with just a few colours?
Paints typically have some titanium dioxide powder, which provide most of the paints' covering/hiding ability, and perhaps some metal oxide(s) for color.
It's all the other stuff, a lot of which will burn away in the kiln, likely including some of the dies that provide color that I'd hesitate over.
The resultant smoke and fumes from burning paints/inks are enough to advise against; how the materials influence the slips' behaviors could be of concern as well.
*I blend bits of clay with water using a blender.
It takes a while, but it works to get a smooth consistency.
Then I run the slip through a sieve to remove sand/grog.
I sometimes use red slip to decorate white and brown ware.
I brush, dab, et cetera the slip on when the ware is still damp - right after trimming.
The moisture softens the ware - timing and care can be important!
After the ware dries some, carving is an option.
Hope that helps!

I too would be very interested in such anti-gravity information, lol!

For the help with the underglaze question. Now, does anyone have a source for an "anti gravity glaze or clay" so when I drop a form it wouldn't  hit the floor and break...........
Again thanks.
Graybeard
 
 
 
 

It’s also helpful to remember that whether you’re using stains or oxides, you’re only adding around 10% or less by dry weight to a given recipe. So if you’re only mixing up a 1 kg (dry materials) batch of slip, you’re adding 100g or less of the given oxide. With powerful colourants like cobalt oxide, 10g or .1% in that one kilo is enough to get a very solid colour. The 10% number would be for some of the lighter coloured stains. Many of the darker blues, greens, black, etc I’d start at 3-5% and see if that gives you the intensity you want. 

In regards to the "What you see is what you get" with stains I have to respectfully disagree. For example if you put a chrome tin red stain in a slip it won't turn out red (even in huge amounts) because those chome tin pink or red or purple stains need low alumina plus quite high calcium to work.  Since slips are naturally high in alumina you are going to loose the colour. Matching the requirements of the stain to the slip or glaze can make a big difference in how the colours turn out. Many stains are not fussy about what the chem of the slip or glaze etc is but there are some picky ones.

Hi Fiona,
Welcome to the Forum!
For colours, there may be some choices that are less expensive?
If making up your own slip from clays*, red, brown/buff and white are common colors.
Underglazes provide a somewhat inexpensive way to get a lot of color; they don't go on the same way slips do, but they do have their uses...
Stains may provide a way to add a few colors to your slip palette.
The per pound prices I'm seeing are $12-18 (US dollars).
At ceramic temperatures, metals persist and provide coloring.
Blue/Cobalt is expensive (but it's come down a lot).
Green/Copper is more reasonable.
Maybe start with just a few colours?
Paints typically have some titanium dioxide powder, which provide most of the paints' covering/hiding ability, and perhaps some metal oxide(s) for color.
It's all the other stuff, a lot of which will burn away in the kiln, likely including some of the dies that provide color that I'd hesitate over.
The resultant smoke and fumes from burning paints/inks are enough to advise against; how the materials influence the slips' behaviors could be of concern as well.
*I blend bits of clay with water using a blender.
It takes a while, but it works to get a smooth consistency.
Then I run the slip through a sieve to remove sand/grog.
I sometimes use red slip to decorate white and brown ware.
I brush, dab, et cetera the slip on when the ware is still damp - right after trimming.
The moisture softens the ware - timing and care can be important!
After the ware dries some, carving is an option.
Hope that helps!

Also , you dont have to invent the wheel. Folk ha1ve been using coloured slip fir a long tIme. I suggest you tap in to other folks testings , select a range you like , remembering the colour of your clay body may have an effect and also your top temperature. Get a palette established for your pottery and then you may have to purchase just a few...to begin with.
All the best

Haha! @Hulk you beat me to it! (What he said^)
Unfortunately most of those things designed for room temperature will completely burn away in the firing. Also, I’m not sure how helpful I can be, because I have no idea of the realities of buying ceramic supplies in Scotland. I can at least give you something to go on. Apologies if I’m giving you information you already know. 
As for oxides/carbonates, there are relatively few that are commonly used in studio pottery, Iron oxide being the most common, inexpensive, least toxic, and easily available. Copper carbonate, manganese dioxide, cobalt carbonate, tin oxide, and chrome oxide, are some others that come to mind. In other words, you won’t need to hunt down every metallic oxide known to man but if you do use oxides your color palette will be limited. That said, I would suggest most ceramic experimenters (probably most potters, to be honest) prefer using Mason stains for coloring both slip and glaze.
Mason is a brand name of ceramic stains and, while I have no interest in promoting them, they are reliable, used worldwide in industry and private studios. “What you see is what you get” after firing, which can’t be said for oxides. 
 

Thank you Hulk. I am going to watch this tonight. 
Betty

Good question!
Does the sitter include a countdown timer?
If so, imo it's a good backup - in case I fell asleep or somewhat - the kiln would shut down when the time's up. I used to set it to about half hour longer than projected firing time, and then adjust from there.
The button on mine, I could push it to the "on" position whether the drop weight was set or not (as long as the timer was set to greater than zero minutes).
Are you able to set the on button?
I'd do that if the cone/bar melted and the drop switch actuated when I wanted a little more heat, a drop and hold, and/or a controlled cool.

FreeVee via Amazon
I'm not remembering if that's how we watched it...

FreeVee via Amazon
I'm not remembering if that's how we watched it...

FreeVee via Amazon
I'm not remembering if that's how we watched it...

Article from yesterday's NYTimes:
Doyle Layne’s Dazzling ‘Weed Pots’ at Kordansky Gallery - The New York Times (nytimes.com)
I'm curious why the Times hasn't enabled commenting on this article?
There's an article in one of year afore last's Ceramic Monthly mags (JAN-21):
Doyle Lane: Weed Pots (ceramicartsnetwork.org)
The Times ran a different article a few years ago...
Adding a New Name to the Canon in Clay: Doyle Lane - The New York Times (nytimes.com)
This one has comments, which can be interesting...

Just watched it with my partner in clay and in life. Movie night. We both loved it. Never had heard of Clarice Cliff. Getting to watch an inspirational feature length movie about an interesting person and geek out on clay at the same time is a rare treat. Thanks for mentioning it @Hulk!

Have you seen The Colour Room  movie?
"It is based on the life of 1920s/30s ceramic artist Clarice Cliff.."
I enjoyed it, for a lot of reasons.
The reviews I've looked at make some valid critical points, yes.
I still like it.

Hi and welcome!
The way you have that question written, I’m picturing you layering clay slabs with toilet paper and then more clay slabs. If the clay pieces don’t contact and blend with each other, they’ll just delaminate, especially once you fire the paper out. BUT. 
There is a technique where you mix wet paper pulp (no more than 20% by volume, but “to taste”)with reclaim slurry, so that the fibres reinforce the clay, and that is indeed called paper clay. You then dry the slurry into a workable consistency, and handbuild with that. The fibres gives pieces incredible green strength and makes attachments quite solid. Paper clay lends itself quite readily to really thin slabs that can be layered with each other, and pieces adhere to each other with just a little paper clay slip applied between. 
There is an article on the parent website here from 2009 about paper clay that was republished recently, and it recommends using cellulose attic insulation. I would personally NOT use this material because it contains fire retardant, and that’s gonna make extra fumes when you bisque your piece. 
This blog post from a former poster, Chris Campbell, does describe how to make your own paper clay quite nicely. If you want to google others, be sure to include ceramic or pottery in your search terms, or you’ll get a lot of paper mache instructions. 
 

The clay will shrink as it dries, which can be  problem if the balloon doesn't slowly leak/shrink.
I found that a non-intrusive way to let a little air out of a balloon was:
- put a strip of sellotape on an accessible part of the balloon
- rub to get a good sellotape/rubber seal
- prick through the sellotape & balloon with a needle
- let some air out
- reseal the balloon with another strip of sellotape over the first
Try it on a spare balloon first.

I was taking a community sculpture class and decided to make a lions head sculpture for a fountain.  My teacher thought it was so beautiful that we should make a silicone mold of it,  I don't think she knew anymore about it than I did.   I bought the expensive spray separator and sprayed it according to directions and covered the head with several tubs of silicone.  I couldn't get it off,  I asked my teacher what should I do and she said to burn off the silicone in my kiln.  That turned out to be a smokey disaster,  the smoke went up 3 stories in the stair well.  My son and I hung out on the balcony until it cleared up,  I am glad it was dark our neighbors probably would have called the fire department with all of the smoke coming out of a 3rd floor window.   My kitchen ceiling was the only thing smoke damaged,   I prime and painted it the next day,  my husband had was out of town.   I didn't tell him what happened,  he did comment on how clean the house looked when he got home.   I had dusted every inch of it, even the ceilings.  Denice

I had a box with about 25 mugs and bowls in it that was sticking out beyond the edge of the shelf it was stored on and while moving things around in the studio, I accidentally hit the box hard enough to knock it and its contents to the floor, destroying every piece...On the upside, my wife got o whole bunch of pottery pieces to put in the bottoms of her planting pots.

Had 80hrs worth of finished damp greenware on a ware cart rolled by a door. I left that evening and when i came back in the morning everything froze because I didnt close the door properly. Big bummer.