Rae Reich

That link only reveals what has been in my cart. Not sure it is working as intended. With respect to. Safe products you can buy food grade epoxy.

It might just be as simple as thinning down the underglaze with water and applying 2-3 coats to get the opacity of colour you are looking for. If underglaze is applied too thick it can definitely lift from the clay. 
What works for me is putting the first coat on fairly thin then when that layer is dry I apply another 2 coats to get an opaque coverage. I mostly use Spectrum underglazes but have also used Crysanthos, Velvets, Speedball, LUGs and homemade underglazes.  The only time I don't water an underglaze down is when doing an underglaze transfer.
 

Shivering is generally considered a clay body problem, the exception being one glaze out of many that shivers while the rest fit.
With slip (the added kaolin is not helping), underglaze, and glaze, you’re working on making four things play nice. If you’ve dropped the slip, you've narrowed it down.
The application and gum are unlikely to be the source or solution of your problem. Adhesion at room temperature counts for very little in this equation. It’s the clay bodies. Wildly different coefficients of expansion from either the glazes or the underglazes. Continue eliminating variables, you’ll solve it. 

just remember that the "chemicals" are ground rocks of differing kinds.   rocks are found in even hotter places than NC.

Hi and welcome!
Not a silly question at all. The good news is, hot won’t affect materials, but humidity might make a few things like soda ash or dolomite clump. Anything that is prone to this can be dried out on a baking sheet at about 175 F in a kiln or oven if it’s a nuisance. 

If you are firing in the cone 10 range and these clay items are just sculpture then Laguna's WSO is the most forgiving clay I have ever found.I feel Bmix with grog is not your best sculpture clay no matter what temp range-get a more loose body
It's more like a cement feel than clay and very tough to crack. I made a 3 foot wall fish from it and it came out fine spanning 3 -12x24 kilns shelves on a waster slab

Are you certain the cracking is clay related, or is it process related?
 
best,
Pres

helena, i noticed that you referred to several cones beginning with zero.  are you working with stoneware or porcelain?    do you have access to a chart that tells you the temperature associated with those cone numbers?   i ask because so many people have been confused and think a higher number following the zero is hotter than the lower numbers.  there are some earthenware clays that are bisqued to 06 and fired to 06 but stoneware finishes much hotter because of its higher density.
the numbers read from  high (cool)  numbers upward to zero and single digits upward toward very high (hot).   my stoneware is mature at cone 6 and i bisque at cone 04 to burn out impurities, the temps are approximately 2240 for cone 6 and about 1850 for bisque 04.   (books out in the studio with accurate #s.)

just FYI, slip made from the same clay as the body of the pieces you make works very well while the piece is still damp from forming.   clay slip soaks into the clay body then but it cannot do that once the piece has dried.
if you read the labels you will find that stroke & coat is a glaze, not an underglaze.
 

Min has a great point especially if it does not perform well. It’s hard to change the weight of the glaze that way, unless ….. it’s not stirred really well. So if you are just skimming water off the top when measuring, make sure it is mixed well and not a whole bunch of ingredients are at the bottom of the bucket.

If the SG was 1.36 to start with but seems thinner now it's probably just because some of the solubles in the glaze deflocculating it.

Most glazes thicken over time if the water is allowed to evaporate. My thought is this was mixed with a lower specific gravity at some point. You could allow this to evaporate to get to a preferred SG. It’s a commercial glaze so no way to know what is in it and if it likely will perform as expected without testing once restored to your preferred SG

Got a notice about this thru a few sources. Laguna has 2-3 other choices with Mahavir Feldspar being the go to
Hard to say if this is permanent or will change again-if You like custar and need custar buy oit now while you can find it.-Last call

Hi Steph and welcome to the forum.
Linda Arbuckle pdf with a good recipe on page 4. What is helpful from this pdf also is the troubleshooting tips on page 3. 
https://www.lindaarbuckle.com/handouts/slips-and-engobes.pdf
Which brands and colours are burning off? 

Does it have a Kiln Sitter?
Start with the lid propped open an inch or two.
1. Bottom switch on. Wait 1 hour.
2. Second from bottom switch on. Wait 1 hour.
3. Close lid. Wait 1 hour.
4. Next switch on. Wait 1 hour.
5. Top switch on. If it has a Kiln Sitter, wait for the cone to bend the kiln shuts off. If it doesn't have a Sitter, you'll have to put cones in the kiln and watch through the peephole for them to bend.

karo, hope the wheel is still available for you to buy.   looks are only important to a fashion model.

Oil might help your foot pedal and governor to work smoothly, but not advisable to have it on surfaces that come into contact with your clay. #0000 Steel wool should smooth out the wheelhead surface. Lubricate with a little water while rubbing out irregularities, rinse well.

I bought a used Brent wheel that had a sticky foot pedal,  everyone here of the forum told me it probably needed adjusting.    I found a video on-line  that showed how to fix it.   It was adjusted totally wrong,  I followed the instruction and put it back together.  It ran like a new wheel.   Denice

In addition, rims are usually compacted more in throwing. 

Oil might help your foot pedal and governor to work smoothly, but not advisable to have it on surfaces that come into contact with your clay. #0000 Steel wool should smooth out the wheelhead surface. Lubricate with a little water while rubbing out irregularities, rinse well.

That is a perfectly good used wheelhead.  You could clean it up a bit with some steel wool.

Here is a picture…
IMG_0370.pdf

@Hulkhas a good solution for your situation. He uses blue tape, used for masking woodwork when painting, to tape off where he wants the glaze to end and peels it off while the glaze is still slightly damp. You could do that, brush your glaze on the lower portion, remove the tape and proceed glazing the rest of the pot.
@Babs carpet covered bat works well, too, allowing you to slop on glaze at will while the pot sits on the dampened carpet, then turning the dry pot slowly by hand on the carpet to rub off accumulated glaze at the base. I would moisten and trim off any chunks of glaze with a fettling knife or trimming tool before turning on the carpet.
Waxing the bottom before glazing could help to keep any glaze from seeping under the base and sticking.

@Hulkhas a good solution for your situation. He uses blue tape, used for masking woodwork when painting, to tape off where he wants the glaze to end and peels it off while the glaze is still slightly damp. You could do that, brush your glaze on the lower portion, remove the tape and proceed glazing the rest of the pot.
@Babs carpet covered bat works well, too, allowing you to slop on glaze at will while the pot sits on the dampened carpet, then turning the dry pot slowly by hand on the carpet to rub off accumulated glaze at the base. I would moisten and trim off any chunks of glaze with a fettling knife or trimming tool before turning on the carpet.
Waxing the bottom before glazing could help to keep any glaze from seeping under the base and sticking.

A second person to hold or wipe might help, if possible.