Types of Clay (Video #26 in the Free Online Glaze Course)

[@missSFDell]

Thank you for sharing all of this, (your), knowledge without requiring a monetary exchange. I think it means a great deal to a good number of folks and, to your credit, brings you into the realm of the legendary figures who value the sharing of knowledge for the sake of knowledge itself.

[@johnbrittpottery]

Original premise of the internet...I think?

[@robfroese8151]

John, thank you for the informative, enjoyable videos you’re making!

[@pooiabeik3042]

That's super awesome! Thank you so much! :)

[@talymiz]

Brillient ! Thank you so much

[@hedvashefaram]

Thank you be very much, exciting and extremely helpful❤

[@lyledeschand863]

Thanks John! I love the library analogy. I'm guessing I'm somewhere around your age.. and was born a visual learner.. KZbin has been the greatest thing for me.. I'm now like a sponge taking in as much as possible.. thanks again.

[@C-M-E]

Mr. Britt, I've become consumed with your series here and learning as much as I possibly can this evening as I love to embed myself in a topic that might yield new and interesting materials down the road. Thank you ever so much for the wealth of knowledge on display, especially including all the chemistry. I've hopscotched around but see I should have started with this one! 😉 I've taken notes and have an absolute load of things to try in the coming days as I'm currently working on several related projects, one being a short of 'ultimate' high temp refractory that is necessary to develop another material. I've had good success in heat resistance to which finding a maximum above plasma I've been able to defeat, though a few days later it will crumble apart on its own due to air exposure, hence I should start from the beginning and adapt binding agents to see where my structure is susceptible to collapse versus hardening at elevated temperatures and staying that way.

[@johnbrittpottery]

Yes have to have good brick.

[@C-M-E]

​@@johnbrittpottery We're actually working on a more castable-type product, which has been really impressive for a day or two, but by day 3 it starts to almost revert to powder. Lots of in-house made aluminas, graphite and carbides, but the binding agents thus far are ablating and/or evaporating above 3500*F/2000*C. I've gotten one sample up to ~6000*F (my pyrometer maxed out at 3000*C) but it has to be quite thick to maintain structure, which we're trying to bind to insulation as a liner-type. It wants to be at least an inch thick to stay together. I feel like I'm missing something simple!

[@johnbrittpottery]

@@C-M-E you had me at 6000F

[@C-M-E]

@@johnbrittpottery I can definitely send off a goodie bag when we get it sorted out. I've always wondered what a nicely polished graphite would look like under a glaze too, and we have loads of that around. 😁

[@1n3o5r7a]

Thank you for your visuals on the chalkboard. This made perfect sense, and a power point would have put me to sleep. You rock.

[@jeangarry3285]

Thank you again for sharing all your knowledge. It's just so excellent that you are not requiring any money!!! I absolutely love your videos.

[@IlyaKalashnikov]

Thank you, John! For categorisation and systematization! 1000 books 📕✨👍🍯

[@johnbrittpottery]

1 at a time!

[@thatoldbiddy2]

I hope you haven't stopped making videos. Your knowledge and way of communicating it is a real asset to the community. thanks for all your hard work.

[@johnbrittpottery]

No. Just busy with life. Got one almost ready..3 more in the works. Thx for the interest.

[@thatoldbiddy2]

@@johnbrittpottery Thanks for the reply! Made my day! 😁

[@johnbrittpottery]

Just finished the Clay Properties...next...Clay Bodies...then Wild Clay...then Firing Cycle.

[@thatoldbiddy2]

@@johnbrittpottery 😍

[@johnbrittpottery]

Just posted a new video!

[@sunwu101]

John, thank you so much for these videos. I love DIY so I'm loving these latest videos. Looking forward to the videos on collecting, processing, refining, and testing local clays! Very excited to see how you approach this. Thank you and blessings to you and your loved ones.

[@starrynight2218]

Loving these videos! Great information, thank you so much! 😊

[@clarapaulo1359]

Tkank you for you videos.

[@hedvashefaram]

very helpful.

[@DisVietVetUSA]

A lot fo these clay are hard to get on the west coast.

[@myzer2011]

Ever so knowledgeable. Great prep of everything as usual John. If I had a sample of a kaolin from an unknown region, where or to what lab would I be able to send it to have it analyzed?

[@johnbrittpottery]

I would try to find a university near by...geology depth. Soil samples.

[@idrisclay454]

How do you one up with names for all the clay?

[@aubreytauer7308]

Got 2 questions for you, one that relates (somewhat) to this video and one that doesn’t. For earthenware/red clays, why does soda firing turn the clay green where the soda hits it (and yet I see a ton of examples in J. Rothshank’s Low-Fire Soda book where the soda seems to have made the red clay look almost sparkly and a very deep red, instead of green, yet one of the potters featured in the book who is local to me showed me how all his red clay exposed to soda turned greenish but the feet or areas where the wads were are orange or red? I’m about to start doing low fire (cone 2-4) soda firing with red clay, black stoneware, and porcelain and really want the gorgeous card red clay, not green! I plan on mostly doing oxidation soda but occasionally some light reduction soda. My question that is related to soda is what really is the best wadding and kiln wash for soda? Seems like alumina and zircon would be the best, though very expensive, but since it is very hard to get zirconium oxide would the silicate in Superpax with the alumina hydrate defeat the purpose of the wadding/kiln wash anyway? Is there anything that doesn’t leave a mark on glazed ware? Whiting and plaster of Paris seem the best, but I don’t see any wadding recipes with Superpax which makes me wonder if using that with the whiting and plaster of Paris or substituted for part of it or even just dusted on the outside and the points of the wadding hot glue gunned to the ware would result in less of a scar? I’m just really surprised to not see ANY wadding recipes out there with Zirconium silicate as part of the mix & wonder why that is, as soda is going to attach to any wadding that has clay as part of it, or silica and alumina mixed together….though I’m not sure I can afford it I was thinking of comparing Superpax wadding made plastic with a little bentonite, hopefully not enough to form glaze with the soda, with wadding made with whiting and plaster of Paris dusted with either alumina or Superpax on the outside, and see what one does better. I can’t afford the super expensive shelves for my little TDI downdraft electric kiln conversion soda kiln so I want the best kiln wash I can make, and I plan to fire on several thin washes of Superpax wash on the soft brick before firing soda in it as I have found several sources saying that doing that is better than using the ITC coverings to slow down the soda eating away at the brick. Hopefully in two years I’ll have the space for a proper wood fired soda kiln being built.

[@johnbrittpottery]

I think it is reacting with iron and other impurities in the clay. I use 50alumina and 50 kaolin forcwadding...more recipes in both books.

[@aubreytauer7308]

@@johnbrittpottery I have the books & additional recipes from articles you published. I just worry with soda that the silica and alumina in the kaolin with more alumina will provide enough material for the soda to form a glaze with. And I’m puzzled why I see very few recipes with zircon, considering it is what is recommended for me to soda proof the IFBs in my converted kiln, and also why I haven’t been able to find any wadding recipes with it- I get it is expensive but so is replacing kiln shelves really frequently! I want to leave as little mark as possible for the wadding for at least the pots, especially if I have to wad part with glaze or slip on it, and have decided on using mostly the whiting and plaster of Paris wadding (which has nothing for soda to react with and just crumbles off or washes off after the firing so little to no grinding) with an experiment dusting Zircopax on some pots over where it touches the pot to see if that will reduce or eliminate the small scar that this wadding leaves. For the red clay turning green in the soda kiln I assumed it had to do with the iron since it only does it with really heavy iron bearing clays, red or darker, but I don’t understand why I see many examples of pots from at least lowfire soda kilns where the red clay is a gorgeous red & even kind of sparkly if they do a slow cooling to get the iron to crystallize in the clay a bit. It doesn’t seem in those examples that those areas of the pot are wadded or masked in any way from the soda, in fact the soda definitely seems to make the clay a lot deeper more beautiful red, and it also doesn’t seem to matter if it is in reduction or oxidation or a mix. I’m just super puzzled why all of the red clay pots shown in J. Rothshank’s book are beautiful reds, except for a potter local to me also in the book which it was hard to tell because you don’t see the surface of his clay at all really because it turns green and we talked about it this weekend and he said all red clays turn green in soda, even lowfire as he does mostly cone 2 soda, & he didn’t know why the others didn’t turn green, as he hadn’t gotten a copy of the book he and his wife were featured in (when I publish a book I’m definitely giving copies to everyone who lets me interview them and gives me pictures!). I’ve asked the author but gotten no response. I’m gonna have to embarrass myself asking in June Perry’s soda Facebook group I guess! I really want that bright red soda color in the book, & I’m not spending all this time developing the perfect claybody with the best red color only to have it turn green when I start soda firing it! It seems like if it was just the iron then the slips with lots of Newman Red in them or Laterite would also turn green when the soda hits them, but they are a beautiful red, darker red the more soda hits them….

[@rashidmohamed50]

Hi there. Love your work. I have a question regarding aluminum oxide. What chemicals or oxides can reduce aluminum oxide melting point if you heat them together in a crucible in a furnace? I know this auestion is not in par with the video above but I dont have your email address. I will appreciate your feedback

[@johnbrittpottery]

Alumina, silica and calcium

[@rashidmohamed50]

You nean silicon dilxide and calcium oxide?

[@rashidmohamed50]

What temperature you think they willl get it to?

[@johnbrittpottery]

@@rashidmohamed50 google alumina/silica/calcium eutetic..think it melts in a laboratory at 2100F

[@rashidmohamed50]

Thank you so much. You Re amazing

[@rondacorkhill1654]

Haha, 1000 books!!!

[@johnbrittpottery]

One book at a time

[@julekhaakter9563]

Your country name

[@johnbrittpottery]

USA

[@julekhaakter9563]

Thank you