Min

I'm all about durability and functionality with most of the pots I make, I like my clay vitrified to the point that it won't leak without glaze, for me it's midrange stoneware or porcelain. Would be great if there was a commercial body that was in the cone 2-3 range that met those requirements. I'ld gladly pay a bit more to fire lower than ^6 and yet have a clay that would be less expensive than a lowfire fritware body. Would probably need to use more frits in glazes than I currently use at ^6 but I think the decreased wear on the kiln elements (and kiln itself) would more than offset that cost.

@Pres, when protection tubes are placed over the tc's it cools down how they read. I believe for L&L protection tubes they say it's 18F. Looking at those cones I would guess you got well over 18F hotter than cone 7. Is putting a cone pack in front of a peep an option? I wouldn't risk an entire load without being able to see the cones during the end of the firing for a new kiln, shut it down when your target cone is down, record the temperature and go from there. I'ld do this for both a bisque load and a glaze load. Just checking, you didn't have a soak at the end of the firing?

If you are making functional ware from either a mid or high fire clay then the clay shouldn't leak even when there is no glaze on the pot. Absorption of under 1.5% is ideal. Clay is at it's strongest when fired to maturity.

What do your witness cones show? Are you getting to cone 9 with that schedule? Laguna's published absorption for the ^10 B Mix with sand is 1.2% and the Maya Red is 1% but these both come with a fudge factor of +/- 1%. I'ld suggest doing your own absorption tests and seeing what your actual absorption is. Link to how to do that here if you need it, about 1/2 way down. Do the proper test with weighing and soaking a sample or two. Since staining of the unglazed clay could be an issue I'ld aim for 1% or lower absorption which I'm guessing you will be over. I can understand your concern about firing to cone 10, maybe time for a road trip? Welcome to the forum.

A plethora of oxide wash recipes from June Perry here. She fires cone 10 but changing the feldspar to either gerstley borate or a boron frit like 3134 would be a place to start testing them at cone 6. I wouldn't recommend any of the ones using barium. @Missy, I've use 30 Red Iron Oxide + 30 Blackbird (an iron plus manganese clay) + 30 Alberta Slip + 10 Rutile at cone 6 for a similar colour as in your image.

Re new elements (in a new kiln or replacements), from one of the Kanthal Handbooks from the wire manufacturer Sandvik in Sweden there is this advice: "Pre-oxidizing the elements is recommended for customers using their kilns at elevated temperatures (cone 6 and higher), or under corrosive or reducing conditions. To oxidize the elements, heat your empty kiln to a temperature above 1922F/1050C with the peep holes open and the lid raised slightly. Holding the temperature there for 6-8 hours will ensure thorough oxidation of the elements, but most of the oxide growth occurs in the first 1-2 hours. This procedure grows a protective oxide coating on the elements before the elements are exposed to any harmful atmospheric conditions. This procedure is usually only done once, but can be repeated as required if the kiln is fired under harsh conditions such as a reducing atmosphere (which actually removes the protective coating)."

A quick look on Standard Ceramics website shows quite a few combinations using the 1198 Layering Base. Link here. Looks like it adds visual texture to all the glazes that were put over it. Congrats on your new kiln!

My suggestion for a QOTW came about from this thread. The thread drifted a little to include a members comment that cone 6 electric is easier than cone 10 gas reduction. My initial thought was yes firing an electric kiln is less time consuming than firing reduction but there are tradeoffs. I’ve always found cone 10 clay nicer to throw than any of the midrange clays I’ve used, the glazes (and clay) are generally less expensive to make for high fire and I also agree with what Michael Cardew said, electricity is a harsher judge of pots than reduction. I find that gifts from the kiln are far less frequent with electric firing vs reduction. Wood firing would top my list as the most work. So, electric or gas reduction firing at any cone you choose, which is more work overall and at what stage of the pot making is it more work than the other? Also, is firing one way more enjoyable than the other? And to make this into a 2’fer QOTW suggestion, another question would be this: hypothetically speaking if zoning / bylaws / fuel cost didn’t come into play would you glaze fire gas reduction or electric?

One females take on this...It's not so much that the scene in Ghost was staged, it's a movie and it's expected. What does bother me about it is when some random guy at a market gives me a pervy look and asks something along the lines if I make pots like that. ick!

When I use wood batts (high density fiberboard) I wire off as soon as I've finished throwing them. Thickness of the wire makes a difference, doesn't have to be a wiggle wire just a thicker wire will do the trick if they are re-sticking to the batt. Also, just make one pass with the wire, if you run the wire under more than once you can get little wafers/layers that are more work to deal with when it comes to finishing the bottoms, especially if you use a sticky high ball clay body.

Nobody warned me clay was an addictive habit.

Red clay + dog + cat = mess. Guaranteed they would find a way to track it indoors! I guess I could have dug a hole and buried it though.

Speaking of cleaning, I tossed a mostly empty bucket of red clay slip in the garbage about a month ago. There was about 500mls left, sloppy but not super wet. Was out for the day then around dinner time there was a knock on the door. By-law enforcement officer with his pad out and a ticket written up for $250- He said "I think you know why I'm here." Nope. Pulls out his phone and shows a photo of the white garbage truck with 2 red egg sized splotches down the side of the truck. He said the garbage truck driver stopped doing his collection, called by-laws and sat there until they showed up then took a picture of my garbage can and the truck. Explained to him it was red clay. Didn't believe me and said the garbage man said it was red paint. I went with a flashlight out to the garbage can and showed him a bit of the clay that was on the rim of the garbage can. Must have pulled his ticket pad out around 10 times during all this. Got a stern lecture about throwing red clay in the garbage. I asked him what was I supposed to do with it to which he said put it in the green waste bin. Didn't care for it when I asked if that would have stopped it dripping on the truck.

Yup! About 60% of the earths crust is silica. Neat video showing "dust" from the Sahara travelling thousands of miles. Diatomaceous earth is approx 80-90% silica, much of the Saharan dust is diatomaceous earth from dried lake-beds in Chad. Not saying it's okay to have sloppy studio hygiene but keep it in perspective.

You are right that the shrinkage will be a big issue. The fired ceramics is going to constrict how the raw clay shrinks and in all likelihood will crack to relieve the stresses. Perhaps you could make a platter or large tile form with earthenware, fire and glaze that then use some of your found old ceramics pieces to do a mosaic in the center of it. (decorative use only) Glazes can change appearance significantly if fired to a higher or lower temperature than originally so there is that aspect to it too.

If you start with hot water you could probably get more than that in there, keep adding it until no more will dissolve. As the water cools the epsom salts solution will hold what it can and the excess will precipitate out. Since we don't know what's in your commercial glaze there is the possibility it is low in clay (kaolin or ball clay), glazes low in clay don't respond well to flocculants so adding 2% bentonite to glazes with less than 10% clay gives the flocculant something to work with. Clay in the glaze also helps toughen up the raw glaze so it's less prone to being dusty and soft when dry. Since you did mention the raw glaze is dusty it might be worth adding a small amount of bentonite to a test amount of of glaze. If you try this the bentonite won't mix with a wet glaze well. You would have to weigh out the bentonite then mix it with a small amount of hot water then blend that into the glaze. See if the epsom salts solution works better with the bentonite added test sample. With some glazes the drips in the raw glaze don't really matter/show in the fired glaze, others not so much. Have any test pots you can fire and see if the drips really are a big deal or not? ^04 for bisque is good, I'ld stick with that. I asked just in case you were bisque firing really low in which case it could account for the pinholes in the raw glaze on your pots. Glaze being thinner is just a band aide solution for crazing, it will still craze over time if the heavier application crazes. Yes! There is always something to learn in this field!

@Pir, I wouldn't add any more saturated epsom salts solution to that batch of glaze. Going forward I'ld suggest just scooping out 100mls or so of glaze and experiment with that by adding just a drop or two at a time then stirring it up and see if it's working with the glaze. Approx 1 teaspoon/ 5 ml per gallon should have done it. I made the mistake recently of using some epsom salts solution that had precipitated out enough to make it useless. Is your solution saturated? What cone is your bisque fired to? @oldlady, agree some clays need dipping in water, I've found it's mostly the open groggy bodies that this helps with to prevent air blowouts causing pinholes in the raw glaze.

It can be, depends on the clay. I never dip pots in water before glazing, they are always dry when I glaze. @Pir, I'ld rub those pinholes over with a dry fingertip when the glaze is dry.

I agree! I was trying to figure out what looked familiar about it even though I've never seen it before. Took me a while but then it dawned on me, the pot on the cover of Robin Hoppers book Making Marks.

Mishima technique is good for fine lines. Scratch the fine lines into leather hard clay then flood the incised lines with underglaze or slip. When the u.g. or slip has dried scrape it back to leave it in the lines, a flexible metal rib works well for this. Other way you can do it is to apply a water based wax resist to the leather hard clay then scratch the lines through and flood with underglaze. Let it set up then sponge off excess from wax. (Forbes wax works well for this method)

Same principle behind the Bailey machines, after the mixing chamber the clay goes through screens which extrude spaghetti like extrusions which are de-aired then clay goes along to the final auger to be extruded. Different method than the Peter Puggers which de-air the mass of clay in the chamber.

I often do this, no problems.

Interesting thoughts here. To rule in or out the microbes or vacuum theory I'ld try taking the scrap, misting it lightly with water then hand wedge it and see how plastic it is. If it's plastic then it would point to the vacuum being the issue. I can't see how the microbes would decrease in the pugger unless it was being pugged for so long that the clay gets hot enough to kill off the microbes. Doubt it would get hot enough though.

We have been considering moving for several years, since 2021 is still an unknown it might be time to pack up my studio/workshop and go for it. Thought of how much equipment and supplies etc I have is really quite daunting so I might just procrastinate a bit longer. 2020 BUH-BYE! (kind of looks like a trimming chuck so I figured I can get away with posting this)

I find that a jiggling pressure like what the dentist does to your cheek when they inject anaesthetic (sorry best description I can think of) helps the two pieces grab onto each other. Did you see any slip squeeze out along the edges after joining the pieces? Welcome to the forum.