LeeAnets

Hello @Hulk and everyone else that helped me through this disaster! I am happy to say I made it to the other side and am now having success in my sculptures! WooHoo! Here are a few pictures and what I learned! (Thank you, @Hulk, for your encouraging words and warm welcome. That alone meant a lot to me.)
1.) @CactusPots A SLOW bisque firing is ***KEY!!*** Especially when pieces are more than 12 inches tall. Sometimes I even preheat for an hour in addition to slow bisque firing now. Out of all my research and feedback, I believe this is the most important part of the solution. I even talked with a tach at Skutt about it.  Thank you, @CactusPots!!
2.) @Min Using "jiggling pressure" when applying attachments also has made a difference! 
3.) @Pres I now use slip made with Magic Water (Magic Water + Clay Body) when attaching elements on my sculptures. This works best FOR ME since I didn't like the "feel" of Magic Water alone. (Also, @Pres, I have tried pinholes inside the vessels when I remember, but since this hasn't been a consistent strategy for me, I am not sure how much it has helped.) 
4.) @Sorcery @Babs I do believe it was possible that air pockets (where moisture could travel to, make steam, and explode) were responsible, especially with a quick bisque fire like my original post showed. ***I've incorporated bending by attachments  as I put them on which makes first contact in the center and then I push out pockets of air to the edges. These air pockets act like vugs in rock formations; they make the perfect place for water to pool, steam and do crazy things!! 
5.) @oldlady When I can, I lay my slab on the table and add attatchments before building it vertically. What I am making doesn't always allow for that, so if I can't do it that way, I make sure I am building on a wooden form or place lots of "back pressure" inside the pot while attaching on the outside.
So…BRAVO and MUCHO GRACIAS to all of you for helping find SUCCESS!!! Here are NEW sculptures...

Hello @Hulk and everyone else that helped me through this disaster! I am happy to say I made it to the other side and am now having success in my sculptures! WooHoo! Here are a few pictures and what I learned! (Thank you, @Hulk, for your encouraging words and warm welcome. That alone meant a lot to me.)
1.) @CactusPots A SLOW bisque firing is ***KEY!!*** Especially when pieces are more than 12 inches tall. Sometimes I even preheat for an hour in addition to slow bisque firing now. Out of all my research and feedback, I believe this is the most important part of the solution. I even talked with a tach at Skutt about it.  Thank you, @CactusPots!!
2.) @Min Using "jiggling pressure" when applying attachments also has made a difference! 
3.) @Pres I now use slip made with Magic Water (Magic Water + Clay Body) when attaching elements on my sculptures. This works best FOR ME since I didn't like the "feel" of Magic Water alone. (Also, @Pres, I have tried pinholes inside the vessels when I remember, but since this hasn't been a consistent strategy for me, I am not sure how much it has helped.) 
4.) @Sorcery @Babs I do believe it was possible that air pockets (where moisture could travel to, make steam, and explode) were responsible, especially with a quick bisque fire like my original post showed. ***I've incorporated bending by attachments  as I put them on which makes first contact in the center and then I push out pockets of air to the edges. These air pockets act like vugs in rock formations; they make the perfect place for water to pool, steam and do crazy things!! 
5.) @oldlady When I can, I lay my slab on the table and add attatchments before building it vertically. What I am making doesn't always allow for that, so if I can't do it that way, I make sure I am building on a wooden form or place lots of "back pressure" inside the pot while attaching on the outside.
So…BRAVO and MUCHO GRACIAS to all of you for helping find SUCCESS!!! Here are NEW sculptures...

Hello @Hulk and everyone else that helped me through this disaster! I am happy to say I made it to the other side and am now having success in my sculptures! WooHoo! Here are a few pictures and what I learned! (Thank you, @Hulk, for your encouraging words and warm welcome. That alone meant a lot to me.)
1.) @CactusPots A SLOW bisque firing is ***KEY!!*** Especially when pieces are more than 12 inches tall. Sometimes I even preheat for an hour in addition to slow bisque firing now. Out of all my research and feedback, I believe this is the most important part of the solution. I even talked with a tach at Skutt about it.  Thank you, @CactusPots!!
2.) @Min Using "jiggling pressure" when applying attachments also has made a difference! 
3.) @Pres I now use slip made with Magic Water (Magic Water + Clay Body) when attaching elements on my sculptures. This works best FOR ME since I didn't like the "feel" of Magic Water alone. (Also, @Pres, I have tried pinholes inside the vessels when I remember, but since this hasn't been a consistent strategy for me, I am not sure how much it has helped.) 
4.) @Sorcery @Babs I do believe it was possible that air pockets (where moisture could travel to, make steam, and explode) were responsible, especially with a quick bisque fire like my original post showed. ***I've incorporated bending by attachments  as I put them on which makes first contact in the center and then I push out pockets of air to the edges. These air pockets act like vugs in rock formations; they make the perfect place for water to pool, steam and do crazy things!! 
5.) @oldlady When I can, I lay my slab on the table and add attatchments before building it vertically. What I am making doesn't always allow for that, so if I can't do it that way, I make sure I am building on a wooden form or place lots of "back pressure" inside the pot while attaching on the outside.
So…BRAVO and MUCHO GRACIAS to all of you for helping find SUCCESS!!! Here are NEW sculptures...

small suggestion.   if you have rolled out the slab of clay to make your form, add the pieces to the slab while it is still flat on the table surface.  folding the slab around your internal form maker will allow the whole thing to be a more consistent construction.   much easier to add pieces when it is flat than working on a standing cube.

I've had this problem a lot, as it's just part of my work.  I think what's happening is that the outside clay layers dry and trap moisture in the slip layer.  A good solid connection is the first part as everyone notes.  An extended time in plastic bags equalizes the moisture between the layers.  A slow dry to basic dry and and then  extended dry to get the internal moisture.   Easy for me in the summer time, not so much now. 
 The bisque cycle should be slow to 200 with a soak before moving on.  Even if the bisque is perfect the attachment can peel up on the edge sometimes.  I think it's just  part of the process to have some failures.  My stuff has gotten much better in this regard with time and practice.
This problem is the number one contributor to my shard pile.
Also, I never liked Rod's Bod.  Much prefer Soldate or S 60

I would be slightly worried about them falling off with glaze in a glaze fire.
Sorce

I agree on this point from that photo -also a lack of slip-I just do not see much slip in there.

I'm anti slip. Just score and water droplets from a needle bottle. Your skip could be the culprit if it's different. I believe slip in a jar can become so bacterially different, it could effect the drying rates. Especially taking into account @liambesawnotes of Fungi gathering metals and minerals, it's what they do.
This picture shows best the smooth parts that were attached well.

 
If you concave the attachments slightly, so the center is first to contact, you will never trap air, or begin at one side and roll it out the other side.
If you're a criminal, like they do fingerprints!
Sorce
 

Great info and thanks for the link.
I did have two survive the load and will go forward with glazing those. (Again, another reason I’m perplexed!) As soon as they finish I will post them. Thanks for asking!
In the mean time, I will try some testing with different variables and see what happens. 
 
Thanks!

@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
 

From what I see in the last photo, your pieces were too dry when you scored them, of uneven dryness between the pieces, and not enough slip was used between the pieces. AS @sorce says: "Those score lines shouldn't be visible at all, that clay should be homogeneous".

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?

Also Ive found if you apply slip to both pieces and then score youll have a far better success rate . The scoring with the slip incorporates it into the clay body better than scoring one side and then adding the piece with slip.

I find that a jiggling pressure like what the dentist does to your cheek when they inject anaesthetic (sorry best description I can think of) helps the two pieces grab onto each other. Did you see any slip squeeze out along the edges after joining the pieces? 
Welcome to the forum. 

yes score both sides and push them hard together then wrap in plastic to equalize a day.

Cool sculpture Lee!
All the other joins survived ok?
fwiw (I don't do much joining - handles, knobs, sprigs), I wet the clay on the receiving end a bit before scoring - just a wet fingertip, damp brush, or sponge; the sheen dissipates as the water is absorbed into the clay, then I'll score. Typically, I'm not joining bits that are exactly the same wetness. I'll also wet the piece to be applied if it's a bit dry, depending. I apply slip to the piece to be applied after scoring, and that only so that it will squeeze out to then be smoothed into the crease, for if both pieces are dampened just right, they'll join without slip. Uhm, I said without slip, however, others may point out that it depends on the clay.
The older gentleman in the Ingleton videos points out in his teapot making clip that scoring isn't necessary (for his process), which I misremembered as slip isn't necessary (about 8:40): 
Throwing / Making a Pottery Teapot on the Wheel - YouTube
There are variables, to be sure. Van Gilder, in some of his vids, wets, but doesn't score or use slip.
That your scoring is so clear (with a few exceptions, where the breaks are) - tells us somethin. Will you post back with more pics of your cool sculptures?

could there have been moisture still lurking in the applied joins so on bisquing
the attached pieces popped off?

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 am with this one...
Especially if you were trying to line up edges well, it makes you seal up the edges first, trapping the air. 
Then, unless you push so hard you break the seal, it'll feel good and attached no matter how hard you push.
What does the scored side of that fish shaped piece look like?
Those score lines shouldn't be visible at all, that clay should be homogeneous. It had to be air, or just not enough "scoochy scoochy". (That's a technical term I love as learned from a HS teacher on YouTube!)
Then Shrink either drying or firing, made them break off. If attached well, you may have still seen cracks where it cracked. Ar other attachments still on and cracked?
Sorce
 

I've been doing clay for a while now, so not a total noob, but have had my biggest disaster in clay to date. I have to admit I have not done a ton of hand building in the last few years, but have done enough to know the basics. 
I was hand-building some larger pieces. Scored and slip attachments to sides. (The same way I have scored for ten years without having issues.) I dried them very slowly under plastic, as I live in northern Arizona and things dry way too fast here. 
They were built with Laguna's Rod's Bod. I built each piece one at a time, during the day, so the slabs would be close to the same moisture. I throw out my slabs for each piece all at one time, by hand, and finish by rolling them between dow rods to get thickness relatively close. I kept extra slabs covered while working on the main piece.
The only thing I can think that may have had an effect was that I let these dry in my garage. (We just moved into this house, so I consider this a variable I haven't dealt with before. In my last house, I dried my hand built items inside the house, and had no issues.) My garage is not heated, but attached to the house, so it never got below 45 degrees F. But the temperature ranged from probably 70 F in the day to 45 F at night. It never fell below freezing, though.
Everything looked fine, but when they were bisque fired, most of the attachments fell off. (see photos)
Could the range of drying temperature have cause my problem?
I am racking my brain trying to figure this out. Please help...

When the bond is not right they can jump off.
Reasons -here are a few
slabs are different moisture content- Slabs are to dry to work well. my guess is this one
wrap them fin plastic for at least a day to even out next time
not enough slip  used or  enough pressure when joining
Not enough time wraped up to equalize moisture content
bisque fired to fast ( I doubt this one)