mobile deconstruction

[david s]

David - what is it you did with the front face of the entry of your new oven? Tile?

I am struggling with how to finish that part of my enclosure. I plan to stucco mostly, but I need to understand how exactly to bring the outer shell up to that front face. I'm thinking to bring the cement board flush with that face, and then render over it with stucco or tile. But that would seem to imply adding lath to the front face, meaning I have to drill holes into the casted piece of art!
Am I on or off track here?

Yes, It's polished concrete. The stones are flattish and placed into the mould which is backfilled then polished after demoulding and curing. There are so many ways to decorate the front. Here's a really easy one (pic) using slate, I was working on yesterday. I cast 8 wire ties into the casting to assist tying into the outer shell (look carefully and you can see two on the right hand side).

Texman: sorry I missed your question. I use Calderys Castflo 1450 ARG which is a proprietary calcium aluminate castable.

[samreg77]

looks good

[Ronstarch]

Hi David, thanks for posting these photos. Question regarding insulation of the flue gallery area: I know you cast the flue gallery as a separate piece. When assembling your ovens, do you insulate around the outside of the flue gallery? Looks like maybe a layer of vermicrete was applied; if so, was that directly onto the casting (no lath)?

[david s]

Yes, 10:1 vermicrete, no lathe.

[ThePizzaGuy]

His thread on the new oven says polished concrete.

I can't seem to find this thread.. link?

[Poochdog12]

hi david, thanks for showing your deconstruction, id really like to know your different types of mixes for your dome layers and the different floor layers. im starting to build mine on a trailer that has a flat piece of chequered plate welded to the frame now. i was going to use a layer of perlite and portland cement mix or possibly vermiculite as its lighter, then a layer of FB board and then the cooking slab ( which i now know to cast in two sections thanks to you, but not sure on the mix.? would i need the needles in the base?) and then i was to make a sand dome and construct my first layer over this ( again not to sure on best mix) and then blankets and more layers of vermiculite or perlite with powdered clay, portland cement. should all this be strapped down to the base? i was thinking about doing that inbetween the two layers of blanket.
alot of questions i know, but it seems you are the wealth of knowledge around here, and i always like what you have to say. thankyou in advance... Danny.

[Poochdog12]

just saw the spread sheet for the mixes... very helpful thankyou. can i use this mix to cast the floor?.

[david s]

Hi Danny,

Sorry, I missed your post. For the floor pieces I use a two piece tongue and groove join with castable refractory cast over a 1” layer of vermicrete. The floor sits atop a cast concrete supporting slab which has a 3” basin filled with loose perlite or vermiculite. Atop the floor pieces are 4 cast and fired castable refractory tiles.
You should hold the oven down to your checkerboard base somehow.
The dome cast is castable refractory, but it’s expensive and tricky to work with, you may prefer to use homebrew.

[Poochdog12]

thanks david.. just so i understand this right ( alot can get lost through text.. nothing better than face to face hey?) from top to bottom you cast concret supporting slab, with a basin filled with perlite or vermiculite, then a layer of vermicrete? with the cast tongue and groove mix slab on that. then are you saying you put tiles on top of that??

sorry if im being thick, but i really want to understand it as i want this to be built right, to help me get out of tarmacing roads for the rest of my days

please give me some feed back on my ideas? i thought about setting 50mm FB boards on vermicrete. then cast a layer of homebrew in two sections like to suggest, and polish this up as my cooking layer??

would i use the ss needles or polyproline needles in the cast floor?

thank you david.

[david s]

I do things a bit differently because I manufacture. My design would not be suitable for a one off. Designing and building complex moulds takes a lot of thinking and building time and is just not worth the extra labour unless you make plenty of castings.
However, as you asked here are some pics of my solution showing the precast supporting slab and two piece floor sections which would give you an idea.
Have you looked at these two well documented builds?
The cooking surface should be firebrick or fired refractory tiles preferably laid loose to allow for expansion and possible replacement.

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[Poochdog12]

nice one David. thats helped and cleared things up for me cheers.

[Poochdog12]

Hi ya,,, can I get a nod or a shake of the head if you think this idea of my floor for my mobile oven is ok?? On top of my checkered plate I’ll lay 5” vermicrete/ perlctete? 1” layer of sand clay dry mix, then fire bricks latex loose on top. Would this work??

[david s]

Yes that sounds ok. Make sure the checker plate is well supported underneath.

[david s]

Post #16 shows a slate decorative arch of which I've built about half a dozen. It's pretty quick compared to mosaic tiles and looks really nice. But recently a customer came back to be saying several pieces of the slate had fallen off (after 12 years) and also another customer reported that one piece on his had fallen off (after around 3 years). As I've never had any reports of tiles falling off I began researching about the slate in the belief that perhaps it could be the material that's the cause. Sure enough, slate is a pretty good insulator, so I believe that there's some incompatibility with its thermal conductivity creating thermal expansion issues against the concrete of the arch. The slate also has a slippery kind of surface and perhaps it is this quality that the tile adhesive finds difficult to bond on to. Consequently I've stopped doing the slate arches.

[david s]

I recently rebuilt the mobile oven. Here is the new one. The wooden trolley was in poor condition, mainly due to being in the weather,I wish I had made it in steel. I decided to repeat it in timber though.