40" Oven on a trailer

[benny8]

We built our 30" oven three summers ago. It was cast out of Homebrew refractory. 500+ pizzas later, we have decided to go mobile for Fairs, Farmers Markets and Catering. We host a number of pizza parties every summer and have held a pizza cookoff the last 2 Memorial day weekends. This oven has held up outstandingly. We plan on casting this oven the same way, with the exception of adding some 1/16" stainless steel gridwork in the dome. It will also be a one piece dome. I will also use some polypropylene fibers as well. I will try to keep everyone up to date n the progress. Right now I am in the process of finding all my materials.Have a good day.

[david s]

Re: 40" Oven on a trailer

When you say 1/16' stainless gridwork, that sounds like mesh. This does not work as well as random stainless steel melt extract fibres developed specifically for refractory reinforcement. There is a tendency for the refractory to want to delaminate if using mesh. The needles are simply mixed in when making up the brew when the water is added, just handle with care to avoid stick injuries. You need to add a min 2% of dry mix by weight.

[mrchipster]

Re: 40" Oven on a trailer

Looking forward to the build. Why a single piece instead of modular? I thought modular alowed for better control stress and prevented cracks that could appear at undesirable locations.

[benny8]

Re: 40" Oven on a trailer

When you say 1/16' stainless gridwork, that sounds like mesh. This does not work as well as random stainless steel melt extract fibres developed specifically for refractory reinforcement. There is a tendency for the refractory to want to delaminate if using mesh. The needles are simply mixed in when making up the brew when the water is added, just handle with care to avoid stick injuries. You need to add a min 2% of dry mix by weight.

David, It is not mesh. I am talking like mini rebar that would be tied together around the perimeter of the dome. Do you think the ss needles would be better? I want to make sure this thing stays together while traveling.

[benny8]

Re: 40" Oven on a trailer

Looking forward to the build. Why a single piece instead of modular? I thought modular alowed for better control stress and prevented cracks that could appear at undesirable locations.

I was thinking one pc would travel better and eliminate any unwanted shifting during transport, even though it will be strapped down. The oven will only be seen inside and cracking is normal. The outside finish will be an enclosed structure, not igloo. Certainly open to suggestions.

[mrchipster]

Re: 40" Oven on a trailer

I was thinking one pc would travel better and eliminate any unwanted shifting during transport, even though it will be strapped down. The oven will only be seen inside and cracking is normal. The outside finish will be an enclosed structure, not igloo. Certainly open to suggestions.

I am not sure which is better, modular or single. But I do have an idea for your secondary insulation and enclosure fill. After the blanket insulation around the dome fill the remaining area with perlcrete at a very low cement mix say 12/1 or 15/1 it will set up like cork and add additional stability as well as provide some insulation. At that ratio it will not add a lot of weight which is also a concern with a portable oven.

[david s]

Re: 40" Oven on a trailer

David, It is not mesh. I am talking like mini rebar that would be tied together around the perimeter of the dome. Do you think the ss needles would be better? I want to make sure this thing stays together while traveling.

Yes, stainless steel needles randomly mixed throughout the casting would be much stronger. If you wrap some reinforcing around the thing it is extremely difficult because you can't place it all the way around, the oven door prevents this.
I have heard reports of brick ovens shaking to bits when travelling so cast ovens are more suitable. I made my mobile dome in a single casting and a second casting for the entry. All large castings are prone to cracking because of uneven heating thus the preference for cast ovens to be made in a few pieces. Yes, my single cast dome has a vertical crack in the back which has not grown any bigger (the oven is eight years old)

[benny8]

Re: 40" Oven on a trailer

I think we will be going with a one piece cast with the needles instead of the mini rebar. Will a 5:1:1:1 mix be suitable for this?

[david s]

Re: 40" Oven on a trailer

I think we will be going with a one piece cast with the needles instead of the mini rebar. Will a 5:1:1:1 mix be suitable for this?

Don't know, I always used the 3:1:1:1 but now always use a proprietary calcium aluminate castable.

[mrchipster]

Re: 40" Oven on a trailer

David, what do you think about the perlcrete in the house?

[david s]

Re: 40" Oven on a trailer

Using perlcrete or vermicrete hard up against the dome in order to give it strength is not particularly productive because it is pretty weak. You can increase its strength by adding more cement and sand, but what you gain in strength you lose in insulating capacity eg doubling its strength will halve its insulating value.
I used vermicrete insulation for my mobile because the fibre blanket available then (at realistic cost) was the older generation unsafe ceramic fibre. The vermicrete probably does do a better job holding the dome in position than blanket would.
Also using perlcrete or vermicrete up against the dome requires much more care in water elimination.

[benny8]

Re: 40" Oven on a trailer

Thanks David and Mr Chip. I think I will be going with the fiber blanket over the top then strapped over that. I will also fill the house with vermiculite. I want to be able to get to the dome, should it fail miserably, and change it out. I used 3:1:1:1 on my dome at the house, so I will go with that along with the needles and polypropylene fibers. Unless I can find a castable refractory mix locally.

[oblertone]

Re: 40" Oven on a trailer

Having pondered at length the problems regarding transporting my (brick dome) oven on a trailer I've decided it probably wouldn't survive; however I did think about inflating a yoga ball inside prior to moving it as a form of internal suspension.

[benny8]

Re: 40" Oven on a trailer

oblertone-that is a great idea with a cold oven, not sure how it would work transporting after an event is finished with a warm oven.

[oblertone]

Re: 40" Oven on a trailer

oblertone-that is a great idea with a cold oven, not sure how it would work transporting after an event is finished with a warm oven.

Indeed, maybe you'll need to hang about and drink beer until it's cool enough !