Cracks in Dome

[Ockenfels]

We have come cracks in the dome of our oven. We used the Heat Stop 50 for our mortar. In August, we went through the curing process. We have used the oven about 4 times. Here are some pictures of the dome. Do we just fill the cracks with the Heat Stop 50 prior to wrapping the Insulation blanket on?

I'm going to attempt to post a photo.

Thank you,
Pam

[david s]

Re: Cracks in Dome

I prefer to drive out the water from the oven after insulating it, but before the outer shell is added. The reasoning is that the insulation will reduce the temperature difference between the inside and outside surfaces of the dome which leads to uneven expansion rates which is a contributing factor in cracking. The downside of this method is that it is more difficult for steam to escape because it is then collecting in the insulation layer meaning it takes longer to dry out the oven.
If I were in your position I'd be filling the cracks with the heatstop, wrap the thing in blanket, do a vermicrete layer, leave for a week to dry in the sun and wind, then start the 7 fires in 7 days, getting progressively bigger. Then the final rendered shell (if doing an igloo) after a further 10 fires.

[oasiscdm]

Re: Cracks in Dome

David is spot on. insulate curing oven before insisting is useless, especially if adding the vermictete insulation layer over the blanket. I have never understood the logic but everyone does it that way.

Another issue you cannot fix is in not laying your brick work on bond. In your photo the joints afl line up. This creates weakness in the structure and is More likely to crack song those lines..