If you put the second dip on while the pot is still saturated from the first dip, it is likely to crawl. The first dip should not be totally dry, but dry enough that the pot can take in the water of the second dip without ruining the grip of the first dip on the clay.
That raspberry recipe likes to crawl. It needs to be on kinda thick to get good color, but that thickness tends to cause crawling with some glazes.
That's cracking, not exploding in that photo. Exploding is hundreds of little pieces, shards in the element grooves, a total mess. It's really, really, really hard to blow up pots in an electric kiln that have already been bisque fired. They have to be fairly moist and fired really fast. The only time I have seen it happen is in raku firings where pieces weren't quite dry after glazing.
What's your firing schedule? I'm thinking that either the second firing is too fast either heating or cooling. Try slowing it down and see what happens.
It is definitely possible for the glaze to crack the pot, especially if it was only glazed on one side (inside or outside), or if the glaze is very thick on one side (in or out) compared to the other. Differences in COE between the clay and glaze can also cause cracking.
Here's another recent thread that has had a lot of discussion on this subject:
When I was trying to figure out pitcher spouts way back when, I threw 6 pitcher necks (about 4 inches tall) and pulled 4 spouts out of each one. By the time I got to 20 I had it figured out pretty well. Then I wedged all that up and threw some actual pitchers.
Take classes. There are a million little things you'll do wrong that a teacher can correct while you're learning. You won't be able to do that yourself. By all means buy a wheel and practice at home, but the lessons are very important. There's a lot of crap in the internet that will only confuse and hinder you.
I have not found bleach to be a good long term preservative. I think that if it was effective, we would see it used commercially since it is way cheaper and safer to store and use than the biocides that are used.
If you have the pieces of bricks that have broken, just use some element pins to hold them in place. When it comes time to replace the elements, replace the entire brick at that point. Kiln cement will most likely not hold the pieces in place, and you'll probably get cement on the elements which is not a good thing. Also pin the elements where the broken grooves are to keep them from flopping out.
If the kiln is rated for 20 amps, it will need a 30 amp breaker. Your clothes dry may or may not work for that, and the plugs may not be the same. I would have an electrician check it al out before doing anything. Do not change out the plug on your kiln unless it's rated for the same amperage, and has the same number of prongs. Some of those older small kilns use a 4 prong plug. Either way, for 2 or 3 pole circuits you can only have one outlet on the circuit, so you'll have to unplug the dryer when using the kiln. If it does work out that you can use the dryer outlet, go ahead and fire it up. If it hits temp then it works.
As for the blank ring, if it's a sectional kiln that has an added blank ring, then the maximum temperature of the kiln will be much lower than without the blank ring. For instance, a cone 10, 7 cubic foot kiln like a Skutt 1027 with an added 4.5" blank ring drops to cone 1. Some kilns have a blank section built into them, in which case the temperature rating on the serial plate will still apply.
Make sure the kiln is 18" from anything combustible and 12" from anything not combustible.
You'll need shelves and posts. Get them locally if you can since they're expensive to ship.
Call Aim if you have specific questions about that kiln.
The other issue with the GG is that if you're using the sliders that hold the pot at the lip, then the lip is being centered, not the foot. The foot is where you're trimming, so that's where it needs to be centered. No matter how perfectly centered it is when you throw it, differences in drying will cause it to become slightly off by the time you trim. Ditch the Giffin Grip and learn to tap center. It's faster, and you can get the foot centered.
Gotcha, does the controller mount to more than one ring of the kiln? what tools will I need to to take it off?
The control box probably mounts to just one section, and there are jumper cords that connect the other sections to it. I would take both a phillips and slotted screwdriver to be safe. I would also take a pair of needle nose pliers and standard pliers as you may need them to get the hinge apart (cotter pins and such). It just depends on what year it was made as to what type of parts it will have on it. With those 4 tools you should be set though. L&L doesn't usually use any hex head screws, but if you have a set of nut drivers take them with you.
If you plan to move it on the pallet, you will definitely need a pallet jack and lift gate. I would uncrate and disassemble it. That way you could move it in a an SUV or van. It would also give you a chance to inspect it.
Sorry, I was out of town since Thursday. If it's truly an unused kiln, then that's a major deal even if you find something wrong with it. When you get it home go through everything and make sure critters haven't gotten to it.