mobile oven-newbie question

[benny8]

Wife and I have been trying to decide on a oven project. Think we have decided on a mobile oven on a trailer. We would like to cast it ourselves. We want one to cook pizzas in, one that will cool quicker for transport, and light enough for a small trailer with a weight limit of 1750 lbs. I am a pretty handy person who enjoys DIY projects. I was thinking a 30" oven, with 2" walls with stainless needles. 2" cast cooking surface on 2" of the ceramic fiber board. Covering the oven with 4" of ceramic blanket. Does this sound like it would work, to achieve what we are looking for? Your advice is greatly appreciated.

[mrchipster]

Re: mobile oven-newbie question

Wife and I have been trying to decide on a oven project. Think we have decided on a mobile oven on a trailer. We would like to cast it ourselves. We want one to cook pizzas in, one that will cool quicker for transport, and light enough for a small trailer with a weight limit of 1750 lbs. I am a pretty handy person who enjoys DIY projects. I was thinking a 30" oven, with 2" walls with stainless needles. 2" cast cooking surface on 2" of the ceramic fiber board. Covering the oven with 4" of ceramic blanket. Does this sound like it would work, to achieve what we are looking for? Your advice is greatly appreciated.

I think the logic is sound but why not use bricks or tiles for the floor.

A removable stainless flue for on the road.

What would be the outer skin? And shape?

Do you have a good axle and shock absorbing suspension on the trailer?

Chip

[JAG]

Re: mobile oven-newbie question

benny8,

I just got my mobile about 2 wks ago (I had mine built) and had been chatting with other mobile operators for quite a while now. I don't think you need to worry about temp when transporting, typically you will shovel out the ash and any remaining embers and put your door on to move it. Like Chip said you definitely want a removable flue. I have a dome shaped oven with a stucco type exterior. If you go with a stucco material check out Sto Powerflex. Also, you may want to consider electric brakes on your trailer. Just my $.02

JG

[david s]

Re: mobile oven-newbie question

Use a tandem axle with shocks too.
If you cast the floor in one piece expect it to crack, which is no big deal really, or engineer joins so it's in pieces. A one piece cast dome is also prone to cracks, but again, it's no big deal, or design it in segments that interlock.

[JAG]

Re: mobile oven-newbie question

I had considered a tandem axle but something to think about is maneuvering. When it comes time you have to move the trailer by hand/trailer jack the tandem axle is much more difficult that a single axle.

[david s]

Re: mobile oven-newbie question

I had considered a tandem axle but something to think about is maneuvering. When it comes time you have to move the trailer by hand/trailer jack the tandem axle is much more difficult that a single axle.

The tandem axle suggestion was in response to the OP saying the oven was to be around 1750 lbs. my own mobile is on a single axle , but is only around 350 lbs. you would not easily manoeuvre a 1750 lb load.

[benny8]

Re: mobile oven-newbie question

Thanks for the replies, really appreciate it. We are just in planning stages right now. We have trouble finding the castable refractory cement around here so might try a homebrew. Could use some recipe ideas for that. The trailer we are looking at has a 2000 lb rated axle. It does have springs, but not sure about shocks. How would you hold the floor down to the ceramic fiber board with firebricks, to keep them from jumping around during transport? We are thinking of casting our oven in pieces to get an idea of the weight, then getting a trailer to fit it. Thanks for looking and if anyone has some info on homebrew castable refractory recipe it would be appreciated.

[david s]

Re: mobile oven-newbie question

An oven is pretty heavy and gravity holds it there pretty well. For mine I cast the dome in one piece and it is held in position by the vermicrete that surrounds it and the outer igloo shell which is attached to the supporting base.
I used a proprietary castable refractory, but the home brew of 4:1:1:1 sand, cement, lime, clay works although you need to add some polypropylene fibres and stainless steel needle reinforcing. Can't say how well this brew stands up to time, but is certainly way cheaper.

[benny8]

Re: mobile oven-newbie question

An oven is pretty heavy and gravity holds it there pretty well. For mine I cast the dome in one piece and it is held in position by the vermicrete that surrounds it and the outer igloo shell which is attached to the supporting base.
I used a proprietary castable refractory, but the home brew of 4:1:1:1 sand, cement, lime, clay works although you need to add some polypropylene fibres and stainless steel needle reinforcing. Can't say how well this brew stands up to time, but is certainly way cheaper.

Thanks David-I think I can get fireclay locally. Everything else is available as well. Where can I get the polypropylene fibers? I'll have to check around.

[benny8]

Re: mobile oven-newbie question

An oven is pretty heavy and gravity holds it there pretty well. For mine I cast the dome in one piece and it is held in position by the vermicrete that surrounds it and the outer igloo shell which is attached to the supporting base.
I used a proprietary castable refractory, but the home brew of 4:1:1:1 sand, cement, lime, clay works although you need to add some polypropylene fibres and stainless steel needle reinforcing. Can't say how well this brew stands up to time, but is certainly way cheaper.

Just called my local block plant and they fireclay and castable refractory cement. The guy wasn't real helpful when I asked him how much a 50 lb bag would do. Normally a bag of cement will tell you how many cubic feet or yards it will do. If anyone has a ballpark guess at how many bags it should take would be appreciated.

[david s]

Re: mobile oven-newbie question

Just called my local block plant and they fireclay and castable refractory cement. The guy wasn't real helpful when I asked him how much a 50 lb bag would do. Normally a bag of cement will tell you how many cubic feet or yards it will do. If anyone has a ballpark guess at how many bags it should take would be appreciated.

Just be careful what you get. What is known as castable refractory is calcium aluminate cement mixed with high temperature aggregates, fire clay, fibres and who knows what else (they like to keep their recipes secret),all you need to do is add water. They are designed for applications in the region of three times the temperatures we fire to. The product is expensive. The calcium aluminate cement on its own, also expensive, relative to Portland (calcium silicate) cement and produced under different brand names, like Cement Fondu is a different to castable refractory.
The recipe I referred to does not contain calcium aluminate cement. If you want to create your own brew with calcium aluminate cement you are on your own. For instance adding lime to it simply accelerates the already rapid hydration process and makes the mix unworkable in anything more than extremely small quantities.

[benny8]

Re: mobile oven-newbie question

I have decided to use David's recipe for the home brew. My brother and I figured out I need a little under 2 cubic feet. I found polypropylene fibers and stainless steel needles on ebay. Tomorrow I think I will toy around with making a couple molds for the dome and one for the opening and vent. I appreciate all the help. I will keep all posted.

[benny8]

Re: mobile oven-newbie question

For you guys who have built ovens before, how much ceramic fiber blanket will a 50 sq. ft roll do? It says on the FB store to do 3 layers and one roll will do a 43" oven. It doesn't clarify if one roll will give you three layers over a 43" oven, or if one roll will cover a 43" oven once. Sorry for all the questions, just trying to get the ball rolling.

[benny8]

Re: mobile oven-newbie question

Found a mold in the modular oven part of the forum by ironpony. Looks really good. I started laying it out today and my dad and I will start forming it up tomorrow. Going to be a fun build for us. We just lost my grandma(Dads mom) so this will be good for him to keep his mind occupied. I will post up some pics as we progress.