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Author Topic: Building a Mobile Brick Oven  (Read 1920 times)

abculatter_2

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Building a Mobile Brick Oven
« on: July 07, 2012, 01:34:00 am »

So, the potential to be able to actually have a job for a week and earn a bit of money has got me thinking about potential ways I could use that money... And I think I've decided on starting my own little business, selling super-fresh, handmade and brick-oven-fired pizzas and breads at local events and farmer's markets.

I've been thinking a lot about it, and it's actually incredibly feasible... Though, there are details which I need help ironing out, which I was hoping you guys could help me with...

My overall plan, so far, is this;
First, I would construct a mobile, wood-fired brick oven, which I'm sure is very doable, but I would like for some people to review the plans and give any opinions or overlooked details, and maybe help with the math before I actually start putting money toward this.
My basic plan for this so far is as follows;
First, I would construct a stainless steel trailer/trolley, which would essentially be something like this:


Which brings me to my first question, what would be the best, sturdiest way to construct this? Should I even bother with welding, having never done it before in my life? Or just buy those flat, rod-like, shaped steel things with the little screw holes throughout them, which I obviously have no bloody idea what they're called? Or should I just drill a hole in some flat, sturdy steel... Uh... What would you call a board?
Obviously, I have only a vague idea of how construction of this would proceed, so help with terms would be helpful...

Next, I would make a reinforced frame on the top of the frame, within which I would lay fireclay bricks. (No need for a mortar cuz the frame would hold it all in, hopefully snugly) These would serve as the foundation for the actual oven, and should be quite thick, 6 inches, with, preferably, an inch or two of concrete cladding and some form of insulation on top of that. (More on the walls in a bit)

The space underneath the oven, assuming there is any, would be enclosed with sheet metal or something equally durable, and used as storage space for firewood and/or the tools necessary for operation.

Then, on top of the foundation would go the dome. I plan on using this oven for practically every temperature range, from pizzas at 900-750 degrees, all the way to danishes, breads, puff pastries, and maybe even pies at 350-450 degrees.
Which means that the walls need to be thick, with a high thermal density (which basically means a high density), so that they store a lot of heat, and release that heat gradually over the period of several hours. (Which is why you generally don't see brick ovens on wheels)
From what I'd heard, 6 inches of fireclay brick, encased in 2 inches of concrete, then encircled with 2-3 inches of insulation, then adorned with a layer of decor should be the minimum for my needs, with the materials I know I can afford.
According to this source, fireclay, which is what I play on using, since it's cheap and is perfect for brick ovens, is 150 pounds per cubic foot, while the concrete I'll likely be using is essentially the same density. Density is my most major impediment to the size of the oven, moreso then cost, since most of the materials are pretty cheap.
Though, to assign a weight target, I'd have to first know how many pounds the cars I have available would be capable of towing on a regular basis... Which I don't... And I'd have to ask about what models they are to find out, which I can't do atm.
I do know that one of my dad's cars, which is what I'd like to use, but probably will not always have available, is capable of towing a motorboat occasionally, which I know is at LEAST 1000lb, probably closer to a ton. So, I would aim for 750-1000lb as a MAXIMUM, while something closer to 500lb or less be a goal. I would still like to be able to push this thing around at least short distances... and, plus, there's always the challenge of finding a ramp to consider, if I ever need to take the thing on top of a curb or in a building. Plus, though it's not that big an issue here in Florida, would the car be able to pull the thing up an incline? Or down one?

Moving along, before I can actually start calculating how much volume of materials I'll be using, I first have to decide on what shape I should use. Which is also related to how I'll actually build the thing...
The most ideal shape, in terms of materials vs oven space and heat reflectivity, would be a half sphere, or igloo-like shape. I would love to have this shape, however, I'm not entirely sure how I'd actually build it... The only way I can think of is to make a mold out of wood, or something, and then pour fireclay on top, let it dry, finish the oven, then fire it by constructing a fire in the oven. However, making an oven entirely out of one solid chunk of almost anything, especially clay or stone, is a bad idea, since the material will expand and contract greatly during operation. This will lead to flaking, then cracking, then crumbling. Not a good thing.
This is why a brick oven is typically made of, well, bricks. They already have the fissures pre-made, so the stone can slide around and expand a bit more without breaking. Though, as it happens, I don't have a large number of circular brick molds on-hand, and I have no idea how I'd be able to construct them...

The other option, which I've heard is just as good in terms of heat reflectivity, would be a rectangle. Which would be much easier to build, but still a bit intimidating... I'd still have to construct some kind of mold for the bricks, and I don't have a carpenter's workshop handy (though I wish I did) so I'm not entirely sure how I'd make them... plus, they'd be mostly useless afterward... Unless I were to make yet another business selling mobile brick ovens, which actually doesn't sound all that bad of an idea...
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sneakey pete

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Re: Building a Mobile Brick Oven
« Reply #1 on: July 07, 2012, 01:37:06 am »

There is exactly this thing parked in someones driveway up the street. They built it into a small (think, less than 2mlong) box trailer.
That could up the cost though, unfortunately.

if i remember, i'll try get a picture of it.
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Osmosis Jones

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Re: Building a Mobile Brick Oven
« Reply #2 on: July 07, 2012, 01:44:32 am »

Are you deadset on it being a wood-fired oven? Gas will get you a far more even cook, easier temperature control, and a faster set up time; in my own experience, a wood fired oven takes a good hour AT LEAST to get a decent coal base going (we used to kindle the fire 2-3 hours in advance).

If you want to sell at things like farmers' markets, that means either arriving ridiculously early, or missing a good chunk of the crowds.
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abculatter_2

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Re: Building a Mobile Brick Oven
« Reply #3 on: July 07, 2012, 01:54:30 am »

There is exactly this thing parked in someones driveway up the street. They built it into a small (think, less than 2mlong) box trailer.
That could up the cost though, unfortunately.

if i remember, i'll try get a picture of it.

Oh, cool! Now that sounds interesting, please do get a picture if you can...

Are you deadset on it being a wood-fired oven? Gas will get you a far more even cook, easier temperature control, and a faster set up time; in my own experience, a wood fired oven takes a good hour AT LEAST to get a decent coal base going (we used to kindle the fire 2-3 hours in advance).

If you want to sell at things like farmers' markets, that means either arriving ridiculously early, or missing a good chunk of the crowds.

I've read and am aware of the amount of time it takes to fire up a wood-fired oven, and I figured I'd just, as you said, arrive ridiculously early and try to plan so that peak temperature is when the crowds are just about to reach their peak.
Though, I'm not absolutely dead-set on wood-fired, I just figured that it'd be the easiest method for getting that much heat, and I figured it'd be a nice novelty thing to brag about...
Is gas cheaper then wood? How would I thread the pipes through the bricks? How much would the piping and other infrastructure cost, how much would it weigh (lighter then firewood, probably) and how difficult would it be make sure it's air-tight?
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Osmosis Jones

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Re: Building a Mobile Brick Oven
« Reply #4 on: July 07, 2012, 02:31:26 am »

I've read and am aware of the amount of time it takes to fire up a wood-fired oven, and I figured I'd just, as you said, arrive ridiculously early and try to plan so that peak temperature is when the crowds are just about to reach their peak.
Though, I'm not absolutely dead-set on wood-fired, I just figured that it'd be the easiest method for getting that much heat, and I figured it'd be a nice novelty thing to brag about...
Is gas cheaper then wood? How would I thread the pipes through the bricks? How much would the piping and other infrastructure cost, how much would it weigh (lighter then firewood, probably) and how difficult would it be make sure it's air-tight?

For the running costs, price depends very much on where you are; we had free wood for our oven (previous owner of the house had left the wood shed positively overflowing, and we only cranked it up for parties). That said, LPG is pretty cheap, and if you have to pay for your wood, I wouldn't be surprised if they came out close.

For set up, gas would be more (it's a mechanically more complicated system), though I would imagine not too much if you're able to do the plumbing yourself. I honestly can't comment much here though, as I have no experience as a plumber. I would instead advise you to visit the local hardware or plumbing store and talk to the staff there. If they know their job, they can probably give you better advice on cost, making things airtight, etc.

One final thing though; if you do go with wood fired, make sure to check out online plans, and talk with people that have built their own (on specialist forums, rather than just here :P). One very important point is to make sure it draws properly. A badly designed oven can be too smokey, lose heat too fast, spew smoke out the front rather than the chimney, or a dozen other minor annoyances that can make your life hell everytime you use it; bearable for a rare, party-only thing, but if it's a source of income that's the last thing you want :P

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abculatter_2

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Re: Building a Mobile Brick Oven
« Reply #5 on: July 07, 2012, 03:22:33 am »

For the running costs, price depends very much on where you are; we had free wood for our oven (previous owner of the house had left the wood shed positively overflowing, and we only cranked it up for parties). That said, LPG is pretty cheap, and if you have to pay for your wood, I wouldn't be surprised if they came out close.

Lucky. :P I'm sure I could get firewood for cheap or free around here, but you're probably right that the two would be about the same if I had to pay for wood...

I think I'll just stick with wood, since it's just simpler, and has less up-front cost.

Also, I should probably mention that this site is what got me interested in this in the first place, and has a LOT of useful information... Though, its creator could really use an English class, and could be organized better...

Posting in a specialist forum is also a great idea, and I'll probably be posting in these two sites about this soon:
http://www.fornobravo.com/forum/
www.permies.com/forums (Okay, this one isn't a specialist site, and this may not be entirely relevant to their topic, but they have a huge amount of people and I know they discuss wood-fired ovens and stoves and such all the time)
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Don't think of it as being besieged by thralls/husks, think of it as having your own personal moat of life hating mutilated menaces

Now wall yourself in quickly