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You can for sure use wadding in an electric kiln to raise pots off a shelf or level shelves but I wouldn't use it on a glazed surface. If you stack plates with wadding between unglazed areas on the plates chances are the plates will warp and deform at mid or highfire. I don't know the price of setters compared to kiln shelves where you are but another option is to purchase small round kiln shelves and use those with short posts for setters. If you try this be careful to line up posts to prevent cracking a kiln shelf when you stack them, make sure the posts line up. When wadding is used in an atmospheric firing such as wood, salt or soda the vapours from the gasses in the kiln flash the pots but the areas where wadding is will resist the flashing.

Laguna has a chart showing all their claybodies and what they are recommended for, including throwing and handbuilding large. https://www.lagunaclay.com/_files/ugd/e5330f_25040094ad64486892fa46e3a38e608f.pdf

One to look at might be this one for the blue, using the pot spar and cobalt carb you have (increase the cobalt carb to approx 1.60) for the blue glaze, not many ingredients in it and it has a good history. I'ld give it a try with the grolleg you already have. I would also try it with an increase the red iron oxide to tone down the blue a bit and maybe 1 - 1 1/2% manganese dioxide if you have some. For the rim and foot I'ld start with a test of a simple 50:50 mix of your wood ash + your local red clay and see what it does. I agree with Mark, the pot you posted looks more like a salt fired pot rather than soda.

Ouch! I've found that most of the time prices for raw materials are less expensive in the US but my local place has tin listed at $59.10 (Canadian dollars) for 500 grams which puts it at $43 US dollars for just over a pound.

So a breaking blue glaze over a white slip over an iron bearing stoneware body? Maybe with an ash type glaze on the foot and rim?

Tacoma Clay Art Center carries Corelite shelves. You probably already know this but if you order anything from Seattle Pottery Supply I would strongly suggest asking for the current price, not prices shown on their website.

Which effect are you looking to get? Everything or rim and foot or ?

I've used dried seaweed, banana peels and copper carbonate mostly so not a huge help with suggestions. Link below with more suggestions, it is behind a paywall but you can access 3 free articles a month. I copy/pasted the chart and snippet from that link below also. If you use ferric chloride wear protective gear while applying it and obviously avoid fumes from the pit firing. https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/A-Pit-Firing-Color-Palette

Underfired glazes can craze for sure. I always stress test glazes for fit before putting them into production.

@Dot, the op hasn't been back since they made their post. I would send them a private message with your extruder question. To send a private message click on their name then the little envelope at the top of the page that comes up and follow the prompts. They will get an email letting them know of your message.

This came up the other day, might help. https://community.ceramicartsdaily.org/topic/41668-midfire-clay-short-when-recycled/ Given your reclaim is already on plaster slabs if it is still fairly wet I'ld put it back into a bucket with some more water and add the blunged bentonite or ball clay/bentonite and slurry mix it again with the plasticizers. The smaller the clay particles the greater plasticity you will get from them, bentonite is much finer than ball clay which in turn is much finer than EPK.

My understanding is the Ardvark Soldate 60 is is 50 Lincoln Fireclay, 25 OM4, 25- 60 mesh sand and 2.5 spar. Yup, it is gritty and very workable and forgiving.

Soldate 60 is great stuff. It's a cone 10 clay but for sculptural firing to midrange would work too. I've known people use it for Raku firing also.

Could go faster to 1500F then resume your regular schedule. edit: I just read your other post about this in the another section, given they are very important pieces the safest bet would be to do the same schedule but without any candling (if you did this). Maybe go a bit faster but not breakneck speed. I'm going to delete your duplicate post.

This thread is a continuation of this one started by @Mark C. regarding the addition of another K2O feldspar to replace Custer: Vardhman feldspar from India. Chart comparing Vardhman with other potassium feldspars plus the analysis I received from Vardhman.

I have the analysis for Vardhman, I'll add a pinned thread on potash feldspar changes. edit: Pin link added here. https://community.ceramicartsdaily.org/topic/41698-potash-feldspar-comparisons-of-custer-mahavir-g200eu-and-vardhman/

Good find Peter. When I look at the analysis for both there are other differences too though. Definitely a fragile mechanism to get the green. Reitz Green with Gillespie doesn't need the lithium carb and dolomite additions when I played around with altering the recipe, the silica is a tiny bit higher in the Gillespie version but given the differences in the Floating Blue recipe that might or might not be consequential, I don't know. A simple addition of iron with a reduction of cobalt would be simple to test Hansen's theory if it translates to Reitz Green also. I suppose RIO would be the logical material to add as long as speckles don't become an issue. Or black iron oxide might be better if you have it.

I would. 1550F is approx cone 012 so pots are going to soak up glaze much faster than a typical 06-04 bisque.

@oldlady emailed me photos but was unable to post them here. These are her photos and show where she has reglazed some areas.

Is this the original you were using? I've also seen this with 1 rutile.

What have you supplied the boron with so far? Same really high alumina? Same batch of rutile?

It might just be as simple as thinning down the underglaze with water and applying 2-3 coats to get the opacity of colour you are looking for. If underglaze is applied too thick it can definitely lift from the clay. What works for me is putting the first coat on fairly thin then when that layer is dry I apply another 2 coats to get an opaque coverage. I mostly use Spectrum underglazes but have also used Crysanthos, Velvets, Speedball, LUGs and homemade underglazes. The only time I don't water an underglaze down is when doing an underglaze transfer.

Is it just the tiny bit of GB you are replacing?

Hi Steph and welcome to the forum. Linda Arbuckle pdf with a good recipe on page 4. What is helpful from this pdf also is the troubleshooting tips on page 3. https://www.lindaarbuckle.com/handouts/slips-and-engobes.pdf Which brands and colours are burning off?

If the SG was 1.36 to start with but seems thinner now it's probably just because some of the solubles in the glaze deflocculating it.