Pres

@JohnnyKgood call, on the dryness of the slabs, sometimes leather hard slabs seem to be damp enough, but really aren't. I usually prefer to assemble when slabs are cheese hard than leather hard. 
@LeeAnets The formula use has been around for years. . . 1 gallon of water, 3 tablespoons of liquid sodium silicate, 1 1/2 teaspoons of soda ash
best,
Pres
 

So as i have been studying this...I am wondering whether this was the culprit. And I am thinking about your pinhole idea, Pres. Here's why...after joining and paddling the pieces together (maybe not having enough pressure as well) I cleaned up the edges and smoothed the creases over with a tool and sponge. That might have sealed their fate, because in drying, there would have been no way for air to escape at all. Now, If I had joined them perfectly there may have been no need for any air to escape, but...
What does everyone think?

I have seen this sort of problem in the past with student pots when I was teaching HS. I don't know as it is a perfect solution, but here is my take.  If any air is trapped in between the two layers of clay that are joined, it may expand enough to cause some expansion cracking thus weakening the joins and causing the pieces to fall off. We used to put pin holes on the inside of the pot where the so that the bottom surface could let air escape into the pot as it expanded. This was often a problem with a lot of the "fairy houses" we used to make, as the students would want to add layers of clay over the base pot for facades. After a few times of trying to figure why some would survive and others would not we started to try the pin hole technique. Had very few problems after that. You may also try magic  water instead of slip, as this was also an improvement in overall construction processes.  You have to remember that HS classes I taught were 50 minutes long (subtract 15 minutes for set up and clean up)  and therefore projects had to be planned out, slabs cut to size, assembled, decorated and finished over the course of several weeks, much the same as your situation.
 
best,
Pres

I have seen this sort of problem in the past with student pots when I was teaching HS. I don't know as it is a perfect solution, but here is my take.  If any air is trapped in between the two layers of clay that are joined, it may expand enough to cause some expansion cracking thus weakening the joins and causing the pieces to fall off. We used to put pin holes on the inside of the pot where the so that the bottom surface could let air escape into the pot as it expanded. This was often a problem with a lot of the "fairy houses" we used to make, as the students would want to add layers of clay over the base pot for facades. After a few times of trying to figure why some would survive and others would not we started to try the pin hole technique. Had very few problems after that. You may also try magic  water instead of slip, as this was also an improvement in overall construction processes.  You have to remember that HS classes I taught were 50 minutes long (subtract 15 minutes for set up and clean up)  and therefore projects had to be planned out, slabs cut to size, assembled, decorated and finished over the course of several weeks, much the same as your situation.
 
best,
Pres

@liambesaw, Know where you're at. Fired a glaze load last night with a green piece that my granddaughter wants to paint. From the heat color I figure at about cone 4 middle switch went off. I quickly shut off the breaker, and checked the fuses, both in good shape. Today the load shows the glaze pots are semi gloss, and the pieces my granddaughter wanted will be perfect for painting with acrylic. I just hope that there is a burned lead somewhere not an infinity switch needing replacement. Elements had recently been replaced last Summer.
 
best,
Pres

Hi folks, 
I have been doing some thinking about the white liner glaze that I have been dipping the hazelnut and the white clays in before spray glazing. So I decided to try a piece without glazing the whole piece in the white glaze, just the inside and neck. I think you can see the difference. Seems like to me, the white is bleaching out the cream rust glaze here, pieces I had sprayed with the cream rust, the variegated blue and the rutile green would always be more blue and green. Interestingly enough, the hazelnut pieces would have more browns in them. 

 
best,
Pres

Busy glazing once again, Honey Jars this time to be out on Thursday for trip Friday.
best,
Pres

The tech I have: electric wheel, giffin grip, pugmill, clay mixer.  No no no no. I mix my own clay and glazes and i fire in a large wood fired kiln. That offsets the tech I have.

I will condider shorting the 1000 foot pier I was dreaming of to say 500 feet
As to the  ceramic tec i'll give up the kiln controlers on an electric (I do not have one) But am willing to finish without one

I'm in the "no" camp as well, except to give up an electric kiln for a woodfired one, if it came with people to help chop wood and fire it.

Harvesting and processing wild clay is an emerging trend; more popular than most realize. Many are processing their own silica, fluxes, etc from wild sources. Natural basalt is gaining popularity for some amazing reds. The best looking celadon I have seen is processed from natural materials. Certainly not profitable or suitable for production: although some are heading that direction. Hunting wild clay is somewhere in the panning for gold category: hoping to find the perfect pit. Firing crystalline; absolute No for me- cannot give up modern kiln controllers.
Tom

Can't really get a hook into anything in my clay-world to serve as a response, other than "no" .

NO!

@liambesawIt would cut my current production down so far it would not be nearly as enjoyable. However, the time on the wheel would become extremely precious!
 
best,
Pres

@Presunderstandable. There's no doubt I'd slow down if I had to dig clay, and I'd respect it and cherish it a whole hell of a lot more.  Might not be a bad thing.

Needed a change of pace and had lots of pieces ready for my wife to paint so I made this, to bad the board cracked but it adds character.

I think the other thing that has made a significant change to how electric kiln fired glazes turn out is the practice of slow cooling. I think that has been a game changer; being able to get the micro crystallization of dolomite mattes etc. that are possible with a high mass hard brick kiln that cools so much slower than the typical electric kiln. I was looking through an online CM magazine from the fifties, an article spoke of using the kiln sitter and propping it back up and turning the dial(s) back on to medium for a few hours. I didn't know it was a thing back then to slow cool (I wasn't around then), it's my understanding that the practice of slow cooling electric kilns really took off when it was written about in the Mastering Cone 6 Glazes book from Hesselberth and Roy. I know that when I went to school in the 90's the electric kilns were mostly used for bisque or earthenware firing. Can't remember anyone slow cooling the electrics.

OK, @LeeU, I'll bite on that, anyone else have something to add or change?
 
best.
Pres

As I remember much of the discussion on other sites, years ago, cone 4 was just above Earthenware range and into stoneware. Others believed that to be a little low, and went to cone 5. Then there were a series of clays and commercial glazes that were designed for cone 4-6.  It became apparent to many that the better surfaces for the glazes often occurred at cone 6. Over the years, I have often wondered what would have happened if we had not had the energy cost rise that precipitated the move toward mid range stoneware. The move towards Cone 4-6 has certainly done well for Ceramics in general as many schools in cities without the resources for gas fired kilns with teachers trained in gas reduction have benefited from the use of electric mid-range Oxidation. 
Aesthetically there is was also another shift as those advocates of reduction moving to mid range carried their likes/dislikes with them and early glazes for mid-range tried to emulate reduction glazes. However over the years the mid range glaze repertoire has become quite broad with many craters and artists ranging far from the olde aesthetic. The richness of surface seen in reduction, can be emulated in mid range with layering of glazes, often by spraying and underglaze/overglaze color and other strategies. Colors achievable at high fire may be synthetically developed as in Copper reds with local reduction.  However much of these are not as pleasing as the colors achieved in High fire reduction. At the same time, now we see more low fire type decoration and glaze done at mid range due to the durability of the mid range vs. the earthenware.  All in all, the last 50 years has done wonders for the science and art of ceramics.
 
best,
Pres

As I remember much of the discussion on other sites, years ago, cone 4 was just above Earthenware range and into stoneware. Others believed that to be a little low, and went to cone 5. Then there were a series of clays and commercial glazes that were designed for cone 4-6.  It became apparent to many that the better surfaces for the glazes often occurred at cone 6. Over the years, I have often wondered what would have happened if we had not had the energy cost rise that precipitated the move toward mid range stoneware. The move towards Cone 4-6 has certainly done well for Ceramics in general as many schools in cities without the resources for gas fired kilns with teachers trained in gas reduction have benefited from the use of electric mid-range Oxidation. 
Aesthetically there is was also another shift as those advocates of reduction moving to mid range carried their likes/dislikes with them and early glazes for mid-range tried to emulate reduction glazes. However over the years the mid range glaze repertoire has become quite broad with many craters and artists ranging far from the olde aesthetic. The richness of surface seen in reduction, can be emulated in mid range with layering of glazes, often by spraying and underglaze/overglaze color and other strategies. Colors achievable at high fire may be synthetically developed as in Copper reds with local reduction.  However much of these are not as pleasing as the colors achieved in High fire reduction. At the same time, now we see more low fire type decoration and glaze done at mid range due to the durability of the mid range vs. the earthenware.  All in all, the last 50 years has done wonders for the science and art of ceramics.
 
best,
Pres

As I remember much of the discussion on other sites, years ago, cone 4 was just above Earthenware range and into stoneware. Others believed that to be a little low, and went to cone 5. Then there were a series of clays and commercial glazes that were designed for cone 4-6.  It became apparent to many that the better surfaces for the glazes often occurred at cone 6. Over the years, I have often wondered what would have happened if we had not had the energy cost rise that precipitated the move toward mid range stoneware. The move towards Cone 4-6 has certainly done well for Ceramics in general as many schools in cities without the resources for gas fired kilns with teachers trained in gas reduction have benefited from the use of electric mid-range Oxidation. 
Aesthetically there is was also another shift as those advocates of reduction moving to mid range carried their likes/dislikes with them and early glazes for mid-range tried to emulate reduction glazes. However over the years the mid range glaze repertoire has become quite broad with many craters and artists ranging far from the olde aesthetic. The richness of surface seen in reduction, can be emulated in mid range with layering of glazes, often by spraying and underglaze/overglaze color and other strategies. Colors achievable at high fire may be synthetically developed as in Copper reds with local reduction.  However much of these are not as pleasing as the colors achieved in High fire reduction. At the same time, now we see more low fire type decoration and glaze done at mid range due to the durability of the mid range vs. the earthenware.  All in all, the last 50 years has done wonders for the science and art of ceramics.
 
best,
Pres

Hi folks, another revision as suggested @Bill Kielb:
Technology for art and craft Ceramics may be defined as any practical evolutionary or revolutionary advancement of knowledge contributing to a ceramic process that allows a more efficient method for enhancing traditional practices with the aid of a system, technique, tool or piece of equipment.
 
best,
Pres
 

Looks fine, maybe “ within” is a bit narrow and  “contributing to” or something to that effect is broader and includes processes and innovation outside art and crafts  ceramics that end up being of significance. Don’t know if “traditional” is helpful in this context maybe enhancing traditional ...... something to that effect.

Technology for art and craft Ceramics may be defined as any practical evolutionary or revolutionary advancement of knowledge within a ceramic process that allows a more efficient method for traditional practices with the aid of a system, technique, tool or piece of equipment.
I would not want to leave out the artists, that do decorative work or the sculptors etc. thus putting in the art and craft. I bow to your editing skills, as you have taken a longer statement and boiled it down to a much more precise statement. . . . thank you.  
How do those of you in the community feel about the statement above.
best,
Pres

Technology for craft Ceramics may be defined as any practical evolutionary or revolutionary advancement of knowledge within a ceramic process that allows a more efficient method for traditional practices with the aid of a system, technique, tool or piece of equipment.
 
I just thought it read a little more concise without changing the definition much.