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Haven't used Sheffield or Bailey claybodies so I'm no help making a recommendation. Hopefully someone will chime in here with their recommendations. I do have a couple pieces of Bailey equipment (mixer/pugger and wheel), I've found their customer support is really good so I'm a bit surprised to hear about their clay having issues with bloating. Did they offer any help with the issue?

I guess where on the continuum you are looking at things from makes it old or new school? New school isn't really new any more for kiln controllers but they have gotten more bells and whistles since the first ones came out. I'm new school there I guess, I love my Genesis controller. Glaze calculation software, is that new school, I'm not sure but it beats the old pencil and paper way of doing calculations. Silicone ribs, maybe those are new school? Clay in boxes, new school? Can't imagine processing my clay from the ground like in the old Isac Button videos. Combination mixer pugger, yup, I'll tick that box too, relatively new school there for studio potters. Electric drill with a mixer attachment vs the old wooden stick to mix up glazes. Using the internet to connect with other potters, is that new school? Reading books, old school I guess but nothing better. Paper and pencil note taking just in case my computer crashes and I loose all my notes because I'm bad at backing things up and not everything is stored in the cloud, old school. I guess I try and take the best from both ends of the spectrum.

Just a heads up to anyone who might substitute Sierralite talc for Amtalc-C98, there is a significant difference in chemistries between the two talcs. A direct 1:1 substitute likely won't work unless it's just a very tiny amount of talc being used. Main differences are in the silica and alumina levels.

No for glaze fires but I would consider bisque firing if I knew the person and they were okay with my ^05 bisque firing schedule for white claybodies. Probably not a huge demand for bisque only so it's probably a moot point.

Speaking of rude surprises, Ferro Frit 3249 full bag price locally is 432. If I could drive across the border and pick it up in Seattle it's 225. Even with the currency exchange rate that's just ridiculous. In general I have found that there has been a steady increase in price over the years. If there is a dip in a chemical price it takes a while for my supplier to reflect that but if there is an increase (like for spodumene because of the lithium price going up for batteries) they are quicker to adjust prices. I have found that if a bigger ceramic supply place like Seattle Pottery Supply carries a somewhat uncommon material and stockpiles it that their prices will reflect the old price for longer than a smaller ceramic supply place does. Example of this was when I went to buy a full bag of grolleg, price went from 60 to 110. Our gas prices are expensive here, filled up last week at 1.70 CA a litre (about 6.50 a US gallon / 7.70 a Canadian gallon), I think that drives up the cost of our clay especially since it's all brought into the area from either the US or Alberta.

Done.

@blackthorn, your ^10 cyanotype + white underglaze looks like fossil dug up from an excavation. Neat stuff! Thanks for sharing your process and results.

Very little shrinkage between bone dry and bisque so it's probably okay not bisque firing it if you were just going to ^04 but since you bisque to ^1 there probably will be more shrinkage so to be safe I'ld bisque it. Measure it before and after bisquing so you know for next time what the actual shrinkage is. That's what I would do. Grog or sand will help the slab move on the shelf so yes I would. Some people use even coils of clay spanning the base of the work, spacing them fairly close together instead of waster slabs and grog (or sand). Welcome to the forum.

@Steven Goldate, the person you are asking the questions to, @why_not hasn't been on the forum since 2018 so it's unlikely they have seen your post. You could try sending them a message, they'll receive an email that they have a message from you via the forum. To message them click on their screen name or avatar, this takes you to their homepage, from there click on the envelope icon near the top of the page and follow the prompts. (to see when a member was last logged in on the forum just hover your mouse over their screen name) Saggars were traditionally used in fuel burning kilns to stack pots within thus avoiding the need for kiln shelves. They also prevented unwanted deposits of ash etc from being deposited on the pots. For using saggars for localized reduction in an electric kiln your main concern in regards to the kiln is keeping the reducing atmosphere away from the kiln elements. Running a kiln vent will help with this as will using as little in the way of combustibles as possible to achieve the results you are after.

I wouldn't do this, you'll likely land up with a bucket of very sticky slip. I'ld wait until you get some more sodium silicate or dispersal / darvan and mix it properly.

@CharliesRadio, seems like nobody here uses that glaze. If you have time it would be best to fire a test tile with the glaze on it before using it for your dragon tea pot.

Yes.

If you don't know how refiring is going to effect the glazes it's a good idea to fire them on a thin waster slab of clay to catch any possible glaze runs. First glaze has already melted so refiring it can make it more fluid. Waster slab doesn't have to be bisque fired first, just make sure it's really dry. Another thing you might want to consider is placing the reglazed pieces in a cooler spot in your kiln. Some claybodies (especially porcelains and smooth stoneware) can bloat when fired a second time due to the body being fired with the extra heatwork. Refires are always a crapshoot but if there is nothing to loose worth a go. Welcome to the forum!

Pugger/mixer just edges out the kiln I bought new for most expensive pieces of equipment. I'm fortunate in that my husband has the skills (and welders etc) that we were able to build my slab roller and electric motor extruder. Years before we built the slab roller I put an add in the local buy & sell paper. Had to phone the add in, don't know if it was a typo or if there really is such a thing and I was misheard but the add came out as wanted: Flab Roller.

I stand for both throwing and handbuilding, only exception is when I'm putting handles on mugs. When I originally started throwing while standing it was because of an injured sciatic nerve running down the back of my leg (piriformis syndrome) and thought I'ld go back to sitting while throwing after it healed, with a better stool, but it didn't take long to realize how much I prefer to stand so I continued to do so. Don't know if anyone else has injured their sciatic from leaning on the edge of a stool while throwing but that's how I did it, took around 5 years to stop tingling/hurting while nerve damage healed. Still have some nerve damage/numbness down the back of that leg. Apart from saving getting up and down like a yoyo it seems there are heart health benefits from not sitting too much so theres that bonus too.

@Clyf, try sending a pm to the member(s) who had some for sale. Just click on their avatar then the blue "Message" box that will be on that members homepage and follow the prompts. They will get an email letting them know they have a message on the forum.

This is a bit like which came first the chicken or the egg.

Stacking determines the load. I cut out a posterboard template of kiln shelf that I put the pots on for each shelf. Planning starts at the design level when possible. For example if I know I'm going to have a bunch of wide bowls to fire I make sure I have pots that will fit in the shadows to maximize shelf usage as much as possible. I try and have a lot of bisque on hand so I can plan the load to have as little dead space as possible.

Crystalline glaze potter, Dianne Creber has some pots done with reduction but the reduction is done after the pots have been fired in oxidation to cone 10. She does either a refire to a lower temperature or starts reduction on the way down from an oxidation firing. From the upper end of 1900F down to 1250F reduction to change the colouring oxides. I remember doing button tests of all the glaze chemicals, there was nothing left of the zinc oxide when fired in reduction to cone 10.

Had a thought about something when posting the recipe above in regards to the whiting. Looking at the eutectic chart, if we know the temperature for the boron calcium melt is 990C/1814F and we know the LOI for whiting is roughly 45% then using sideways logic it would make sense to go slow and possibly do a hold around 990C/1814F to clear the bubbles in boron glazes containing a significant amount of whiting. Does that seem logical?

@BobMagnuson, wondering about zinc eutectic and reduction. If the temperature for zinc oxides eutectic point is 1030C / 1886F (using 0.54 CaO + 0.46 ZnO + 0.13 Al2O3 + 1.39 SiO2) have you found a difference between oxidation and reduction eutectics for zinc given zinc will start to volatilize in reduction around 900C?

Or....it could be viewed as another map, to help get out of the chem wilderness. Adding my voice to say thank you to @BobMagnuson for both sharing his calculator plus making himself available here for questions and comments.

Hi Bill, Okay, so I'm just poking around with the EuCalc, I'm using a Mac. I took Sue McLeod's clear from Glazy and plunked it into the calc. Don't know if one would get the same results using Excel? Looks like there is excess alumina and silica that isn't taken into the melt but I could be reading this wrong. I'm heading out early tomorrow a.m. to go wilderness camping, won't have a chance to play with this some more until I get back Sunday night.

There was a recent thread where glaze eutectics was brought up. Stemming from that was a link to an article by Robert Magnuson in the Feb 2018 Ceramics Monthly which contained a link to a eutectic calculator, "EuCal", he created. Magnuson discusses an interesting aspect of eutectics, to quote from the article: "One of the most interesting aspects of eutectics isn’t how they melt, but how they solidify. When a eutectic mixture cools from the molten state, the individual components all stay molten together until they solidify. When they do, a transparent glass is formed. If the molten glaze contains ingredients that are not part of a eutectic, these ingredients may solidify separately while the glass is still liquid, leaving tiny crystals suspended in the glass, producing opacity and other effects in the final glaze. But, if a glaze contains only eutectic mixtures, a transparent glaze will result. Very few glazes are based around a single eutectic and most incorporate both alkali (R2O) and alkaline earth (RO) oxides. Any combination of the eutectics of Na2O, K2O, and CaO (see left) will result in a transparent glaze. For such a neat trick, it’s surprising you don’t hear about it more often. If you have ever tried to formulate a fully transparent glaze by trial and error, you know it isn’t easy to do—unless you know this trick." Since the time of that publication Magnuson has updated and revised his EuCal. Version 1.8 added borate eutectics for the alkali fluxes and the latest version, 1.9, added a calcium borate eutectic. This could be very useful as it now brings mid and low range glazes into play with the calculator. There are some provisions, see the read me file linked below. Given that not everyone has access to the links in the article Jennifer Harnetty asked Magnuson for permission to link the read me file plus the eutectics calculator here to which he very kindly agreed to. I've added the links to the updated version below. I realize this isn't an area that gets a lot of discussion but perhaps as time goes by as more people get familiar with the calculator it can be utilized as a stand alone piece of software or perhaps in tandem with Stull charts. Lots of food for thought here. Link to the Feb 2018 article here: https://ceramicartsnetwork.org/ceramics-monthly/ceramics-monthly-article/Techno-File-Using-Eutectics Link to the User File here: https://ceramicartsnetwork.org/docs/default-source/default-document-library/eucal_1_91_user_guide.pdf?Status=Master&sfvrsn=a5d9b703_5/ EuCal_1_91_User_Guide.pdf Link to the EuCal here:https://ceramicartsnetwork.org/docs/default-source/default-document-library/eucal_ver1_91.xlsm?Status=Master&sfvrsn=6fc99709_9/EuCal_ver1_91.xlsm