Russ

We have plenty of freeze thaw cycles here in the high "desert". ..About 5 months worth yearly. Hence the cement plaster! But there are still high end homes  that are adobe and mud plastered. Its an aesthetic that some love and are ok with an annual coat of mud to keep it natural.
Once plastered the adobe will last for many years... ie; Taos Pueblo which has been around for about 950yrs... and they only use mud plaster.
Oh and there is stabilized adobe which has an asphalt product mixed in... the same stuff that is painted on below grade cinder block.

Adobe is easy to make provided you have sand and straw and is quite stable. Typical size is 10x14x4. Needs to be plastered with a cement based product just for weather protection. Been used for thousands of years here in the southwest. I work with it quite frequently in Santa Fe. Probably your best bet for what you have. A wooden form is easy to use and make to form the adobe.

All this talk about wood firings being a long drawn out affair isnt necessarily so. IF you like the effects of a true natural heavy buildup of ash then a lengthy firing is what youll need. If youre like me and you like the warm toasty clay body reduction without the muddiness of ashes on your glazes then some type of "fastfire" setup is required. My kiln is a fastfire type but with major modifications from Olsens original. The 2 fireboxes and chimney are all on the same side making it easy on the stokers and stokemaster to see whats happening in each fire box. I would call it a crossdraft / downdraft hybrid.  The interior stacking space on mine is 80 cubic ft.... huge compared to most gas and electric kilns. This being said our last firing from dark to cone10 took 4 hours 50 minutes. the hottest parts gets well over over cone12.  Smoke is only a small issue early in the firing when temps are low and fuel to burn is more than the temp can handle.. thus the smoke that exits the chimney.  the total wood burned is around 1/2 cord ..all of it pine softwood. (Softwoods have a very long flame compared to the much shorter hardwoods) something to think about when selecting a fuel.

Fred Olsen has an old but good book on kilns. He addresses the principals of shape, size, intake, exhaust, firebox, chimney for several types of kilns.  If you stick with these youll be in good shape.

All this talk about wood firings being a long drawn out affair isnt necessarily so. IF you like the effects of a true natural heavy buildup of ash then a lengthy firing is what youll need. If youre like me and you like the warm toasty clay body reduction without the muddiness of ashes on your glazes then some type of "fastfire" setup is required. My kiln is a fastfire type but with major modifications from Olsens original. The 2 fireboxes and chimney are all on the same side making it easy on the stokers and stokemaster to see whats happening in each fire box. I would call it a crossdraft / downdraft hybrid.  The interior stacking space on mine is 80 cubic ft.... huge compared to most gas and electric kilns. This being said our last firing from dark to cone10 took 4 hours 50 minutes. the hottest parts gets well over over cone12.  Smoke is only a small issue early in the firing when temps are low and fuel to burn is more than the temp can handle.. thus the smoke that exits the chimney.  the total wood burned is around 1/2 cord ..all of it pine softwood. (Softwoods have a very long flame compared to the much shorter hardwoods) something to think about when selecting a fuel.

All this talk about wood firings being a long drawn out affair isnt necessarily so. IF you like the effects of a true natural heavy buildup of ash then a lengthy firing is what youll need. If youre like me and you like the warm toasty clay body reduction without the muddiness of ashes on your glazes then some type of "fastfire" setup is required. My kiln is a fastfire type but with major modifications from Olsens original. The 2 fireboxes and chimney are all on the same side making it easy on the stokers and stokemaster to see whats happening in each fire box. I would call it a crossdraft / downdraft hybrid.  The interior stacking space on mine is 80 cubic ft.... huge compared to most gas and electric kilns. This being said our last firing from dark to cone10 took 4 hours 50 minutes. the hottest parts gets well over over cone12.  Smoke is only a small issue early in the firing when temps are low and fuel to burn is more than the temp can handle.. thus the smoke that exits the chimney.  the total wood burned is around 1/2 cord ..all of it pine softwood. (Softwoods have a very long flame compared to the much shorter hardwoods) something to think about when selecting a fuel.

All this talk about wood firings being a long drawn out affair isnt necessarily so. IF you like the effects of a true natural heavy buildup of ash then a lengthy firing is what youll need. If youre like me and you like the warm toasty clay body reduction without the muddiness of ashes on your glazes then some type of "fastfire" setup is required. My kiln is a fastfire type but with major modifications from Olsens original. The 2 fireboxes and chimney are all on the same side making it easy on the stokers and stokemaster to see whats happening in each fire box. I would call it a crossdraft / downdraft hybrid.  The interior stacking space on mine is 80 cubic ft.... huge compared to most gas and electric kilns. This being said our last firing from dark to cone10 took 4 hours 50 minutes. the hottest parts gets well over over cone12.  Smoke is only a small issue early in the firing when temps are low and fuel to burn is more than the temp can handle.. thus the smoke that exits the chimney.  the total wood burned is around 1/2 cord ..all of it pine softwood. (Softwoods have a very long flame compared to the much shorter hardwoods) something to think about when selecting a fuel.

Fred Olsen has an old but good book on kilns. He addresses the principals of shape, size, intake, exhaust, firebox, chimney for several types of kilns.  If you stick with these youll be in good shape.

I fire exclusively with wood... even bisque.

Not all cement board (tile backer board) is equal. Within the last year Hardibacker has come out with a "waterproof" type which will not absorb water. ASK if youre not sure about which one is which. The water proof is several dollars more than the regular hardibacker.  That being said I have used a plaster wedging  table with a removable canvas cover for 30 yrs or so. No problems for me but I dont slap the clay on it either.

Have you tried using a rib and compressing the heck out of the bottom while on the wheel?

Have you tried using a rib and compressing the heck out of the bottom while on the wheel?

Have you tried using a rib and compressing the heck out of the bottom while on the wheel?

Have you tried using a rib and compressing the heck out of the bottom while on the wheel?

Medex maybe?

Kyanite is available in 200 mesh and would not detract from the smoothness of your clay.

This mold discussion brought up a memory of mixing beer in a batch of clay so it would get plastic faster and have better mold.   I don't know if it really works,  we were just following instructions of the MA  students.    Denice

My guess is that the slip or underglaze contains a fair amount of cmc gum, bentonite  or other "brushing medium" which makes them to flow or brush easier BUT they act as a thickening gel and therefore capture and retain a large amount of water.... you put it on and the water soaks in leaving only the ug or slip behind. The water content in there might be 50% or more leaving you to have to fill several times.  You could try to make your own slip or ug without the gel producing chemical. There are plenty of recipes out there and you could the adjust them to your preference.

My guess is that the slip or underglaze contains a fair amount of cmc gum, bentonite  or other "brushing medium" which makes them to flow or brush easier BUT they act as a thickening gel and therefore capture and retain a large amount of water.... you put it on and the water soaks in leaving only the ug or slip behind. The water content in there might be 50% or more leaving you to have to fill several times.  You could try to make your own slip or ug without the gel producing chemical. There are plenty of recipes out there and you could the adjust them to your preference.

NOOOOOOOOOOO!!!!!

Glaze pinholes aren’t caused by organic additives to the glaze burning out. When we talk about organic burnout being a possible cause of pinholing, it’s from the carbonates/sulfates etc that are chemically bonded to the glaze materials themselves. Things like CMC, glaze additives and wax are gone and vented out of the kiln before anything starts to happen on a ceramic level. So, I don’t think you have concerns there.
As far as whether or not wheat dextrin will work to help stick the glaze to the pot or make it more brushable, it’s always worth an experiment in the name of science. As always, do a test with a small amount before adding it to a larger batch, and don’t use it on something that’s precious until you’re confident in how it'll turn out.

Seems alot but the entire population of the earth could stand in the state of Texas and still have plenty of room left over.

not even 100 pennies!   run away, fast.

Not only will a homogeneous mix of 2 glazes give you a different result than the same 2 glazes layered, the order in which you layer them will often give you a third set of results. And varying the thickness of the application in any of those scenarios can add yet another layer of interactions.
There’s lots of us that can give you a super technical rundown if you love the science, but the simple explaination is that when you layer the glazes you’re creating localized areas of 3 (or more) different chemical reactions. There’s areas on the pot of glaze 1, glaze 2, and whatever the mix of the 2 of them would be. When you mix the 2 thoroughly, you’re only getting the one thing. 

Ive used portland cement as a glaze for many years.  Mixing a small amount at a time and using it within an hour works best.  I then fire it to c10 and it looks quite similar to a runny ash glaze.  Portland is comprised of lime, magnesium, iron ox, and silica.
Like Callie said its not something you want to mix alot of because it sets fairly fast.