Mobile Forno Finally started!!

[aferaci]

What about putting some type of reinforcement in a perlite/portland slab. Like maybe wire mesh, rebar or even fibers like they put in concrete to make it stronger. Does anyone think this would work or be feasible. I really want to get rolling on this thing and the rigid insulating board is out of my price range right now.

[gjbingham]

You can try to skimp, but if you're going to do it right, save your money up and buy the board. I doubt you can build a great oven that will last a long time without spending some real money.

[aferaci]

So all of the other people on this forum who made their ovens with vermiculite or perlite slabs were skimping too? Thanks for answering my original question-you were so helpful

[Ken524]

Originally Posted by aferaci

So all of the other people on this forum who made their ovens with vermiculite or perlite slabs were skimping too?

They weren't skimping. The vermiculite/cement base works very well. If you do a search for messages about vermiculite on the forums, you'll see that it's stable and can take the compression forces of an oven. But it is very susceptible to chipping and shear forces. That's why we are concerned about a mobile installation. We don't want the "shake, rattle and roll" of a trailer to damage your pride and joy.

CanuckJim suggested Matrilite 18, a castable product. That might be a good cost vs. stability compromise.

[aferaci]

Well, this problem seemed to solve itself today. I was riding by a jobsite today and noticed that they had some left over AAC (autoclaved concrete or Aerocrete) concrete leftover. I talked to the jobsite super and after I told him what I needed it for he agreed to let me have as much as I needed for a case of Budweiser. This stuff is nice and thick and strong but it's so light. A 8"x8"x24" piece only weighed about 5 pounds. So I will go get this stuff tomorrow and post pictures of it.

[Ken524]

Budweiser seals yet another deal!

[RCLake]

For a case of Bud , who got the better of this deal. No just joking, I looked into this as my floor insulation and Dmun posted a thread that had discussed it. Still think it may be a cheap way, if it would hold the weight.

Show us how you are going to do the door. Could be basically a plug attached to a good looking door.

At least have the beer cold when you deliver it and you can probably have a couple.

[gjbingham]

Sounds like a good and solid solution for a mobile oven. Great find!

[aferaci]

Well, I went and got the AAC block today. Below are some pictures of them. I got 12 block in all that measure 8"x12"x24". I'm not sure if I'm going to use the end with the hole yet and just fill the hole with perlcrete or if I'm just going to cut that piece off. I am going to split the block down the middle of the 8" side though, making 2 4"x12"x(16" or 24") pieces per block. The guy at the jobsite said these block go for about $12-$14 a piece and I got all 12 of them for a $11.99 cae of Budweiser. And he told me that if I needed more that I could come back and get them. What a deal!!!

[fortran]

I have done a little research into this, more in terms of a "luggable" oven than something mobile, but testing would be the proof.

Working from the Pompeii design, I would think using 1 fewer courses of cement block would be something to consider, maybe 2 courses less, since the "ground level" is now above axles. You could however stay with the same number courses, since the room underneath is good for wood storage I gather.

Mortar is not very strong, typically less than 10% of the strength of the concrete blocks. Probably the thing to do is to dry stack the concrete and then surface bond the blocks. Normal surface bonding for housing, uses a fibre reinforced concrete mortar, but with bridge infrastructure of concern around the world, civil engineering has started looking at stronger systems. One paper used carbon fibre reinforcements in epoxy for the surface bonding. You do need to use a primer on the concrete, and possibly special epoxy (concrete has a high pH). You would want to surface bond both sides of the block, and you wouldn't need to fill the cores with concrete and rebar. Which would save you a fair amount of weight. I would plan for a steel bolt to come up from the steel frame of the trailer through the hollow cores, to a steel plate on the top of the stand, to hold the stand rigidly. That should allow the stand to be rigid enough that the oven shouldn't see any flexing.

Any wood in the structure, such as at the top of the stand to place the stove onto, might be better if you impregnated it with a penetrating epoxy. It won't see sunlight (UV), so you don't need to protect the epoxy. This would probably remove rot from consideration. A mobile oven would probably see some water getting onto that wood. Exposed structural wood that was treated with epoxy should be painted with a good paint. If you paint it before the epoxy has completed curing, the epoxy will hold the paint very well (oil based paints).

I would think it would be a good idea to "shave" the bricks making up the domed oven. That would probably help to minimize how much mortar you use, and at the same time might even increase how much area mortar is on. My feeling is that if the mortar is thick anywhere, any flexing of the oven is going to make that mortar crumble.

It would be interesting to see how this project goes.