Satan's back and he's going mobile...

[Satan]

Okay, after building my first WFO https://vimeo.com/41400572 with the help of some great FB members (THANK YOU!) I'm going to attempt to build a refractory cast oven for a mobile application. That said, I've crunched the numbers and wanted to run them by some of the seasoned members to see if I'm heading in the right direction

Here's what I have so far and if anyone notices a wrong calculation PLEASE shout out.

Specifications:

Interior diameter: 120 cm (47.5")
Interior dome height: 43 cm (17")
Door height: 28 cm (11")
Door width: 53 cm (21")
Flue diameter: 20 cm (8")
Landing: 30.5 cm (12")
Wall thickness: 7.62 cm (3")
Dome surface area: 4300 sq inches (30 sq ft)
Total floor surface area for ceramic fiber board: 2910 sq inches (20.25 sq ft)
Cubic volume of exterior sphere minus interior sphere divided by 2 + 20% = 14,725 cubic inches (8.52 cubic feet) This formula was to calculate how much cubic volume of refractory cement I'll need.
Hearth surface area = 1810 sq inches (12.6 sq ft)

Here's what I think I'll need for materials:

22 - 25 kilo (55 lb) bags of refractory concrete mix + 20% fudge factor (I came up with a 25 kilo bag = approx .40 cubic feet).
60 sq ft of 1" x 24" ceramic fire blanket (2 layers of 1" thick blanket).
20.25 sq ft of 2" thick ceramic fiber board.
54 - 9x4.5x3 fire bricks (40% alumina) for hearth + 20% fudge factor.
Stainless steel needles (Quantity TBD). Any advice would be greatly appreciated.

To add even more difficulty to this build I am building this oven in Colombia, South America where sourcing and high cost make it an interesting project to say the least (Patience grasshopper). To my knowledge it will be the first mobile wood fired oven in Colombia and possible all of South America.

One last thing... I plan on modeling my build after this build http://www.fornobravo.com/forum/f43/...uild-7866.html If anyone has any better ways of casting a dome please don't hesitate to guide me.

Love to hear your comments. Thanks in advance for any input you can provide.

[david s]

Re: Satan's back and he's going mobile...

That's a pretty big oven for a mobile one. You will need a trailer with a tandem axle with the springs rated for the weight, also make sure you include shocks. Stainless steel needles should be added to the refractory mix at 2% by weight as a minimum. The correct name in the trade is stainless melt extract fibres. If you intend doing roasting or baking in the oven as well as cooking pizza, then you will need a door and a rebate or reveal for the door to sit against. This needs to be included in your design when making the mould.Also consider making the flue pipe removable otherwise it will tend to flap around in transit and create sealing problems where it enters the oven.

[Satan]

Re: Satan's back and he's going mobile...

david:

Thank you for your reply to my query. Your points are well taken and yes, it is a big oven and for that reason I'm considering reducing the size to a 110 cm diameter oven. My design does incorporate a reveal for using a door and based upon reading other threads here on FB about mobile ovens I have a removable flue planned for it also.

For the trailer I was planning on a rubber torsion suspension appropriate for the weight of the trailer and load and yes, I'm going with a tandem set up.

I read about the 2% by weight for the melt extract fibers and I'm still trying to figure out the end weight of the oven. That said, do I simply take the dry weight of the 22 bags of refractory cement or is there another formula I should know to calculate the end weight?

Thanks again.

[david s]

Re: Satan's back and he's going mobile...

You will need to add the dry weight of the refractory and all the other stuff, which is about half the total water added, insulation, render for outside shell (if an igloo) or all the materials for the sides and roof (if a dog kennel), floor bricks, supporting slab flue and outer decorative arch (if you plan on having one)

[Satan]

I'm back after a very long delay... Life got in the way. Here's a video of the cast refractory duel fuel mobile oven pizza oven I built in Colombia, South America...

[Satan]

Here's the Avanzini Drago P1 Plus in action after adjustments made per Prisca Avanzini...

[Satan]

This is one of the life events that got in the way and delayed the finish of my mobile oven...

[Gulf]

Hi Nata,

The oven turned out great, and the gas assist is very interesting. I have some questions about the smokehouse. It is very nice. I try to do my cold smoking on days when it does not get above 40-45 degrees F. We try to not let the temperature inside the smokehouse get above 70 degrees F. I took the liberty of checking the average monthly temperatures for your area of South America. You live in a very mild climate. I can't see much diiference in any month of the year (lower 80s-lower 60s). A friend of mine uses an air conditioner in his smokehouse to extend the number of days per year that he can smoke. What method do y'all use?

[Satan]

This smokehouse is not located in South America, it is located where I live 4/5 months per year which is Huatulco, Oaxaca, Mexico. The temperature here (I'm currently in Mexico) is very warm and at times down right HOT. To mediate this I use the same method your friend does, an air conditioner. It's a portable unit that I move in and out when needed for cold smoking. Note at 3:31 of the smokehouse build video and you'll see at the rear of the smokehouse an eight inch diameter hole. This is where the exhaust vent duct exits the smokehouse. Truth be told when I cold smoke I do not use the main firebox, I use an alternative method that I found I can better control the amount of smoke and more importantly the amount of heat produced. You also see at 3:31 a small valve (about 18" above the 8" diameter hole). It is a gas valve that I use when I want to add an additional heat source in combination with the main firebox. I connect a large gas burner, the type used to heat a Paella pan. Note: Google "paella burner" and you'll see the type I'm referring to. With the fact that my smokehouse is constructed using SIP panels it can handle the extra heat plus it retains it exceptionally well.

To be clear, I now live near Rionegro, Antioquia, Colombia most of the year and that is where I built and use the new mobile duel fuel pizza oven. There it would be ideal for a walk-in smokehouse but up until a couple of months ago I wasn't in the optimum living situation to have one. Now, after buying some acreage and in the process of building a house, my plan is to build another walk-in smokehouse pretty much a duplicate of the one I built in Mexico with the exception that In the next one I won't have the need for A/C since the temps are quite moderate at the elevation I'll be living, over 7,000 ft above sea level in the foothills of the Andes mountain range.