Should I worry about this cracks?

[kallipigous]

I got up to 700 degrees curing today and this crack widened a little. It's still a little too hot to stick my head in the oven and see if it's affected the brick internally but so far I think it's just the external render. I was going to start insulation tomorrow but should I grind and fill this first? If so how much curing should I do before I insulate again after filling it? Can you assume that repaired mortar dries pretty quickly?

[david s]

I believe it is better to drive the water out of the oven after insulating which results in less of a temperature difference between the inner and outer surfaces of the refractory. But that is too late for you now so you could try firing the oven up a bit and fill the cracks while it's still warm. However, once you have some cracks they are usually still there, repairs are generally not very successful. Don't beat yourself up, many ovens have cracks. It won't fall down and probably won't get worse and will not effect the oven operation.

[kallipigous]

Yeah I left the insulation off so I could see what cracks appear and could deal with them. I filled it while it as still hot and it looks fairly tight now. I'll fire it up again and see if any smoke escapes. I've now added the insulation blanket so I should easily see if heat is escaping.

[RandyJ]

That is the wonderful thing about insulating first. Unless the crack is real bad you won't know it is there. It also might not have formed in the first place. But it is unlikely to fall in on its self. One of the big positive things about the dome.

Randy

[kallipigous]

I must admit now it's insulated it's nice not having to look on it and worry any more.

[V-wiz]

My oven had developed a crack similar to yours, i too left the insulation off. What i did was after it had cracked i applied high heat glue on the outside of the oven where the cracks had developed. Patch the cracks with the special high heat glue, put the insulation on and move forward.