“I was wondering if you might have any info or resources for cob oven on trailers?”
Here’s my thoughts and experience, over and above what’s already in Build Your Own Earth Oven:
I wouldn’t try to put a cob or earthen oven on a trailer myself. I do know of one guy who did but he had to do repairs on the oven before the year was out but I haven’t heard from him since, so don’t know the whole story of his oven. Maybe it’s doing just fine. It’s hard to imagine that unfired earth would be able to withstand prolonged exposure to road vibration without serious cracking and ultimate failures.
The only trailer oven I’ve made was lightweight, hi-temp cement, as described in the book. I’ll refer you to that and Dan Wing’s article about trailers for ovens, which is here.
I haven’t yet heard from anyone who has successfully done what I’ve only seen in Mexico, a site-built temporary, wood-fired, masonry oven mortared with mud so that it could be quickly and easily disassembled and moved to another town for another festival.
There are myriad other ways a person might build a quick oven, including pre-cast, fitted pieces of fired clay (or hi-temp refractory cement) that could be constructed into a shell over a brick hearth — or even a metal dome over a fire-brick floor, which I suspect would work fine for pizza. I would think that just about any one of these options would be much cheaper than building a road-worthy (and safe) trailer.
I’d love to hear from folks who’ve got experience they’d like to share on this one, especially anyone with photos of Mexican festival ovens.