This customer had his oven for at least 5 years now. He painted the dome using high heat paint and covered the oven when it was not being used. This year he noticed all the paint doubled and bubbles were forming all over. When he tried to pull the paint off, big chunks of the outside layer of the oven came right off together with the paint.
The great news is that this oven is fine and there aren't any indications that warrant concern regarding its functionality or integrity based on the photos provided. Although this customer stated they kept their oven covered, there are indications that it's been exposed to harsh weather elements, otherwise, the mortar wouldn't deteriorate to this capacity.
(The series of photos above is a case where the oven arrived in this condition upon delivery. The wooden crate broke off and hit the top of the oven which resulted in the oven getting damaged.)
(Photos 1 & 2 are from another customer whose oven was damaged by an ice storm.)
The good news is that this can be easily repaired! We recommend the customer apply a new layer of mortar to the dome of their oven to restore it. The best mortar for this repair is the Sakrete Fast Setting Gray Fast Setting Cement 20-lb Patch in the Concrete & Mortar Department at Lowes.com (This can also be purchased via other hardware stores and Amazon).
(After removing the chunks, slowly pour in the mortar on the affected area. Scrape off the excess to make the top layer smooth)
Once they've applied the mortar, they can then coat it with the Authentic Pizza Ovens Ultrafire Repair Kit and paint it again if you'd like to. Your oven will now look good as new!