KAST O LITE 26 CRACKS

[mariom2]

 It happened during the firing. Tried to be gently, 5 minutes, cool for a while, 10 minutes cool half hour, 15 minutes, cool.........cracks!!

Too hot, too soon!!....I do not know.

Guess now it needs fixing.  Read in another post to butter it and use the same Kast o lite??.  Any comments.  No metrikote, no plastic, no ITC100 around here.

[Buzzkill]

This may be one of the few places that refractory cement or mortar actually has a good use in a forge.  I'm not sure the cracks are big enough to be able to fill with cement or mortar though.

those cracks would not prevent me from using the forge though.  You'll definitely want to monitor them to see if they get worse.   Unless you sift the Kastolite to get the bigger aggregate chunks out I don't think you'll be able to get any noticeable amount into the cracks.  You could rough up the surface, butter and apply more Kastolite, but it would be more like a patch over the cracks. 

[Frosty]

Is your forge insulated? If not it could be the cold shell outside and HOT inside. Also they both run lengthwise through the forge. The shell will have the most change in size and shape around the circumference and squeezing or stretching a cylinder through the center would tend to cause cracks lengthwise.

I'd say those cracks are insignificant. I wouldn't worry about them unless pieces start falling out there shouldn't be any problems.

Frosty The Lucky.

[mariom2]

Thank you for the replies.  Yes, it is insulated.  2 inches of ceramic blanket.

[mariom2]

Floor is a separate cast on the same kastolite.  One crack is under the floor and the other on top.

They have gone worst, very thin but almost all the way to the back, if this happens I will eventually have two separate pieces!! 

[Frosty]

Ah HAH! The crack in the floor is because it's so thick in the center and thin on the edges. The edges heat faster than the center and expansion must go somewhere. OR is the arrow pointing at the main liner under the floor? Uneven heating again as the floor is causing the main liner to heat much more slowly. The uneven heat expansion and contraction under the floor is probably stressing the rest of the liner. Masonry isn't flexible so it cracks. All normal.

Masonry cracks, look at any concrete slab or large casting it has cracks. My Kastolite liners have similar cracks and they don't effect anything. Honest.

Besides there isn't anything effective to do about those. I think you've probably flame cured it more than necessary, it's time to let it get yellow hot and do some work for you. I sure wish the Kastolite people would post information about mixing and curing on the website but they don't, it CAN be found but it's a real PITA and then you have to convert it from full sack quantities.

The cure procedure the maker recommends for Kastolite is 100% humidity @ 60 -100f. for up to 7 days for max strength and temp rating. I put mine in a plastic bag, dumped in about a gallon of water, twisty sealed it and left it for something like 24 - 36 hrs, I don't recall. It begins to set in about 30 minutes and finishes setting in an hour or so, then into a wet cure environment. Kastolite does NOT dry, it hydrates and sets the same way Portland cement concrete does and follows a cure so similar the maker uses it as the default cure method.

Running a progressive heat cure is a recommendation for another brand/type castable refractory. It won't hurt Kastolite but it won't help either. Commercially they plaster and gunnite patch large areas in furnaces that are still red hot. One of the tings I like about Kastolite so much is how insensitive it is to mixing, handling, cure, etc. It's literally WAY easier to use than scratch making bread.

Frosty The Lucky.

[Jealdi]

Scratch making bread is super easy... so that makes me feel like this step will be very easy once I get there. 

[Frosty]

Kastolite likes to be kneaded too but it takes more force the aggregate is crushed so it keys and interlocks, it does NOT move easily. 

I LOVE the feel and smell of kneading proofed bread dough. The only thing beats that is the smell of baking bread just before it's ready to come out of the oven. 

Do you toast warm out of the oven bread? It's so good it makes me wish I could bake bread one slice at a time. Mmmmmmm.

Frosty The Lucky.

[Jealdi]

Most of the breads I make have to rest first. Except pretzels... I always eat one of those while fresh. 

[Frosty]

Okay, that's an old family term, not literal. Maybe still warm from the oven is more accurate. Yeah, thump the loaves, pull the pans to a cooling rack and when thumping the bottom of the pan tells you it's cooled enough to slip out, tip the loaves out of the pan onto the cooling rack until they're almost room temp.  Warm out of the oven meant it would melt butter but warm. Too warm and you might as well just tear it to pieces, it won't slice. 

Deb thought I was nuts the first time she saw me a drop slice of fresh warm bread in the toaster. I smiled and asked, "You like fresh bread, you like toast?" And held my hands palms up. . . The look that came over her face was priceless. It's the best toast on earth. 

Frosty The Lucky.

[Jealdi]

Yeah, I always have a piece before it gets too cool. Usually just slather it with some blackberry or strawberry jam though!

[Frosty]

Toast it. You'll thank me later.

Frosty The Lucky.

[Jealdi]

Next time I bake, for sure.