Babs

Test the black mentioned above by Min. The cobalt may bleed in certain conditions and some glaze movement, at C 6 a great black.

I think it's probably not asbestos being made that recently. However even if it's not, the silica fibers from whatever they did use aren't really any better, so wear a mask and act like it's asbestos.

The original recipe for Magic Water by Lana Wilson is: 1 gallon water 3 Tablespoons liquid sodium silicate 1 1/2 teaspoon soda ash  -OR-
1 gallon water 9.5 grams sodium silicate 3 grams soda ash You will find many variations of  this on the web if you do a search. I use the one listed above.  
 
best,
Pres

My guess is the handle got bumped and hence the crack . If it was fine for years of use then cracked it got bumped . If it cracked right away(1st month) its a poor connection

if its just been bisqued bisfix will work fine for this. See above video
There are other menders that work as well like Marks mender and highfire mender for glaze wares-I have used them all

Bisque Fix?
 

The things being discussed here is are not necessary to good glaze formulation. I've been making durable glazes for 30 years without ever looking at a Stull chart or Katz's papers. Learning the basic of glaze formulation- fluxes, stabilizers, and glass formers- will serve you just fine, and allow for tweaking formulas to increase durability and adjust glaze fit for your clay body.
Commercial glazes are not necessarily any more durable. They all take testing as well. Clear glazes are generally quite safe if they're free of lead and cadmium, which most all glaze recipes being used nowadays are, and they don't have the heavy metals (colorants) in them that are likely to leach in a poorly formulated glaze. The benefits of mixing your own glazes are that they are much less expensive, and you can alter them as needed to fit the clay body you're using. If you know another potter that has a good clear glaze, by all means ask them for a recipe.

I use the heavy canvas fabric that you can purchase with the slab roller,  I have one for light clay and the other for dark.  I also like the idea of the fabric backed vinyl,  I will have to dig through my husband's scrap box and see what he has.   We have been on a buy only what you really need binge for a couple of years.   We also have been donating truck loads  of stuff to the DAV,  I don't think he would give away upholstery scraps for his cars.  His mother died during COVID and we ended up with most of her treasures  in our basement.   We have enough for one more truck load  and I will be able to walk through my sewing room.    Denice

Hi and welcome to the forum.
Couple things, Mayco Stroke and Coat is a highly pigmented glaze, you don't need to brush a clear glaze on top. Second thing is Mayco recommends a minimum firing of cone 04.
Could you post a picture of the problem tiles? Might help clarify what is going on.

Looking at your pictures I agree with others that the form was thrown too thick, and needed more aggressive thinning to make up for the difference.  I Love throwing large bowls, and other forms for the kitchen, and these require a major amount of wedging of the clay, Mastering the clay on the wheel(coning up and down), and aggressive pressure from the base up into the cylinder walls. Throwing a bowl starts with a rounded interior when opening up, and most of the pressure during pulling is from the outside with more of a flat fingers on the interior keeping the curve of the base into the cylinder then when sufficient pulls have thinned the base the walls are shaped from the inside. My favorite tool for this is a large wooden spoon with the handle cut off and the edges rounded out where the handle had been attached. Whether a dish(flat interior bottom) or bowl (rounded interior bottom) the trimming is important to make certain there are no areas in the base that are thicker than normal fo any thrown piece.
All this IMHO, meant to be helpful, not critical.
best,
Pres

Looks like typical thickness blowouts to me. I've seen them in that location before. I'm surprised that the preheat didn't prevent it, but that could be related to the location in the kiln, stacking, and how quickly the firing ramped after the preheat.

Thank you for the photos. I believe you made the pots too thick. The outside profile vs. the inside shape shows it, to me, clearly. If the bowl is in fact 20” wide, the foot must be well over an inch thick in some areas. 
There are many variables (relative humidity, clay body, temperature of candle, etc.), an eight hour candle ought to have taken care of most of them, but honestly it’s just too thick and blew up. Water did that. 

Is it a damp area? Loiks like the outside profile and inside profile neans a pretty thick area which if any dampness lurked inside the pot wall at that point could cause a blow out if it was close to an element, flame? 

What a great story and such a fine example of helping others along a difficult road for many.. That young potter has been given such a selfless gift , hope it is infectious.
 

What a great story and such a fine example of helping others along a difficult road for many.. That young potter has been given such a selfless gift , hope it is infectious.
 

Put a resist on the emblem so glaze doesn't cover it. Or carefully wipe glaze  off after glazing.
Or get an on glaze decal made up.
Good luck.

Even signingbup for a class can be expensive.
Go to a clay supplier, ask for a liw fired clay. Make stuff with it, lots of "how to" stuff on line, a lot not useful, a lot generated by very good potters. Then you will get some idea re your natural feel for the clay.
Simple safe kiln can be made fot backyard..check what's allowed re outside fires.  You dont have to fire your first pieces. Just wet down your pieces, wedge and use again!
Afterwhich, if smitten by the pottery bug, and within your means and time constraints, join a class.
 

+1 for taking a class or joining a group studio, especially if you’re looking for a hobby. In addition to all the reasons listed above, you will be around other people who are excited about clay, and the community in these scenarios really accelerates your learning. 

Try staining the emblem, wiping off high area. . .  . . do not wipe off the rest of the pot, but make certain has been dampened before the staining and wipe. Then glaze. The additional water in the emblem should cut the absorption of the glaze to some degree allowing the stain to show through revealing the emblem.
 
best,
Pres

In addition to wiping you can also spot saturate with some water by either pre-dipping in water or dabbing with a soaked shaped sponge. I teach it to my students when they don't want to wax the bottoms of their pots.

1. Apply water to areas of pot you want to be less glazed.
2. Apply glaze as normal.
3. Give a little shake, blow on the less glazed spots, or dab with a sponge.

Put a resist on the emblem so glaze doesn't cover it. Or carefully wipe glaze  off after glazing.
Or get an on glaze decal made up.
Good luck.

Put a resist on the emblem so glaze doesn't cover it. Or carefully wipe glaze  off after glazing.
Or get an on glaze decal made up.
Good luck.

I guess I was thinking along the lines, the only person you can change is yourself.

If that’s the glaze, then wiping across the emblem with a sponge may do it. I’m with @neilestrick on stamped food surfaces. Do it on the bottom or find a glaze that fills it and still shows the details. I like that stamp. 
Nice looking work! 

Put a resist on the emblem so glaze doesn't cover it. Or carefully wipe glaze  off after glazing.
Or get an on glaze decal made up.
Good luck.