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clg763 05-15-2012 01:34 PM

Help me design a mobile oven install on the cheap!
 
Hello everyone, I have a 1200lb 120cm modular oven arriving in two weeks and I need to design a mobile base for it. Ideally, I would make the base out of steel, we do have a welder at the farm but the only one who was really gifted with it, passed away last year. I don't trust the welds of anyone else to hold my precious oven (except a professional welder of course, but that gets very pricey). If the style of welds for a pizza cart can be made so that they are extremely easy, let me know, I would prefer that way.

My other option to consider would be a wood cart, I know wood is no where near as rigid as welded steel but I have some wood-working experience and I think it is possible. In some ways, I am more comfortable working with wood because it is a medium I understand. I could make the base out of 6x6's and set the oven on 2x6 joists with 2x4 cross bracing to strengthen it from lateral loads.

I have picked out some 10" pneumatic tires on casters rated for 500lbs each to wheel it around the property.

My next issue to tackle is insulation, I want to do this as cheaply as possible, I do not have hundreds of dollars to throw at several ceramic blankets and insulated bricks for the hearth. I would just do a vermiculite/portland base using a 5:1 ratio but I am concerned about the strength of this in a mobile application. Do you have any input for a cost effective insulated base for a mobile oven?

For the dome, I was thinking of just getting a single ceramic blanket and covering it with 6-8" of rock wool. I heard that rock wool can stand up to more heat than fiberglass insulation, with the ceramic blanket taking the brunt of the heat, the rock wool wouldn't be exposed to nearly as high of temps. It is my hope that this would be a superior insulation to vermiculite/portland and weigh much less as well.

My last item is the exterior housing, I see most people using steel frame to build the roof and sides, is there a reason that I couldn't use wood after all of the insulation I will be putting in there? I know there are clearances that must be maintained depending on the situation, I am open to input here though. I have never worked with metal studs so I have no idea what is involved with that.

Thanks in advance.

clg763 05-18-2012 11:08 AM

Re: Help me design a mobile oven install on the cheap!
 
Anyone?

Bueller?

Bueller...?

david s 05-18-2012 12:06 PM

Re: Help me design a mobile oven install on the cheap!
 
You need to start with a solid base, probably concrete or say 1/4" steel plate to support the oven.
When I built my mobile, trailerable oven I was trying to make it as light as possible and I used 3" thick steel reinforced aerated concrete in the hope that it would be strong enough and also double as the floor insulation. It has cracked in a couple of places from one side to the other. The thing still holds together because it sits in a steel cradle, but I wouldn't do it again that way.
It is generally considered that a timber frame is likely to flex when moved and therefore be unsuitable, but I'm sure it can be done successfully providing you use appropriate cross bracing. The rest of your plan sounds doable to me.

clg763 05-21-2012 08:15 AM

Re: Help me design a mobile oven install on the cheap!
 
Thanks for all of the advice and input, I am re-considering a steel frame but looking into the cost of steel, I am amazed at how expensive it is adding up to be. Just running the numbers, I can't pull things together for less than $600 or so for just the materials. Is there somewhere that people go for cheap steel? Local places have large minimum orders or change a ton (like Lowes ect) and online stores aren't cheaper after shipping costs. I may have to look into a used utility trailer.

azatty 05-23-2012 10:16 PM

Re: Help me design a mobile oven install on the cheap!
 
Go to a scrap metal dealer. New steel is stupid expensive. You'll have to hunt around for the pieces in the yard, but you'll save a lot of money. That's what I did for my reverse flow smoker. The only new steel on it is the 3/8" plate for the firebox, and that was nearly $300.

clg763 06-05-2012 03:06 PM

Re: Help me design a mobile oven install on the cheap!
 
***Update***
I couldn't find anyone selling scrap metal in my area, they all sell to foundries, so the cost of steel and complication of finding a welder priced me out of a steel frame.

I built the cart out of wood over the weekend, it is quite sturdy but I am doing a few things to make it absolutely rigid. The biggest issue I have had is that due to it having 4 wheels and no suspension, when I go over un-even ground, the frame wants to flex to keep all the four wheels down. Typically, one of the wheels will just go in the air so I decided to switch to mounting a pair of wheels in the middle and using jacks in the corners to level it.

I have finally sourced some insblok 19 an hour away and will be putting 3" down underfloor. I will be using 2" of ceramic blanket insulation and 7" of roxul insulation after that. My hold-up now is deciding what to do for the stucco finish. I don't trust myself to stucco mesh and get a decent shape, I probably need to use vermiculite concrete first. How little vermiculite concrete can I get away with and what ratio should I use? I already have plenty of insulation so it really isn't needed for that, I would rather save the weight.


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