Mobile oven design Buoy...HELP

[P712]

I've got a 48 inch buoy and a tandem axle trailer. What do I do? Anyone have any design ideas? I was thinking I'd lay my brick floor on a steel deck with insulation, then cut the buoy in half and weld half to the steel deck over the brick floor to keep it in place. I would then cover the dome with insulating blanket, and finally 4 inches of cement based insulation layer.

But then what?

[Lburou]

Outside the box

Wiley (one of our members) built a metal oven....You can read about it here.

His oven might give you some ideas. A picture of your buoy would stimulate our collective creativity, if you can get it posted here.

[Neil2]

Re: Mobile oven design Buoy...HELP

No matter what you do, your pizza oven won't float.

[P712]

Re: Mobile oven design Buoy...HELP

Hilarious. I'll try to remember that

[metalmaster]

Re: Mobile oven design Buoy...HELP

this might give you some inspiration http://www.fornobravo.com/forum/f43/...oven-7739.html

[P712]

Re: Mobile oven design Buoy...HELP

Well, here we are. The trailer and dome were dropped off at a friend's shop (he does custom metal work. If you can't see from pictures, they built up 1/2" sides and laid 1/2" plate on top and welded the dome on top. The dome is 57.5" in diameter. I'm a bit stumped on where to go from here. My plan is to use the other half of the buoy to trace out oven deck and cut bricks accordingly so they can be placed in like a puzzle. Do they need to be mortared down? I was planning on using insulating board between steel deck and brick floor to minimize heat loss. Bricks are 3" refractory leftovers from now bankrupt Geneva Steel blast furnace. Also, is it logical to cover dome with foil and cast my own vermicrete in batches like Wiley did? I'm not an engineer and need a little coaching.[IMG][/IMG]

[metalmaster]

Re: Mobile oven design Buoy...HELP

where is the door going to be?

[dmun]

Re: Mobile oven design Buoy...HELP

Forget the foil. It's completely useless.

I'm worried that with your dome welded to your support structure, that heat will zoom down to the trailer structure with alarming speed. No matter how you insulate inside the dome below the floor, or the exterior of the dome you may end up with something that's too hot to stand next to.

Vermiculite concrete may be too brittle for a mobile oven.

You may want to think about some thermal mass as well, as soon as you get that thermal bridge problem sorted.

[Tman1]

Re: Mobile oven design Buoy...HELP

Yes, I think Dmun has a VERY valid point. Perhaps you have a solution you haven't shared.

[Wiley]

Re: Mobile oven design Buoy...HELP

Wow!, I'm come late to this party...

First an observation:

When you started this thread you said you had a 48 inch diameter hemisphere and now it is a 57 1/2 inch hemisphere. If you search the archives you will find the posts on a WFO using a bouy. Some exchanges between that builder and myself are on my "Steel Dome Oven" thread. That WFO became "Dented Bouy" and is used commercially.

Dented Bouy used his bouy as the outer shell to his WFO. The interior dome was a 48 inch diameter steel hemisphere (ex propane tank). Outside that interior dome (in the interstitial space between the two shells) lie the refractory heatsink/reservoir and the insulation. The hearth bricks lie upon insulation and that insulation is supported by a steel deck.

Welding the inner dome to the base is IMHO not the way to proceed for the reasons stated by Dmun (and others). I am guessing that you welded the half dome to the plate in order to secure it and the finished WFO against movement during transport of the finished WFO.

I'm at a loss as to suggestions as to how to proceed from this point. Everything that I think of would be usurping your inventiveness and involve in cutting the dome off the trailer.... and I'm thinking such suggestions would not be welcomed.

As for Dmun's comment about foil being useless in this application (making sure there is no bond between the cement/fondu/refractory and the steel dome) I would have to say I hold a contrarian view. Steel and concrete/cement have a particularly good adhesive bond as those who have failed to completely wash a shovel used in placing concrete can attest. When applying the refractory to the exterior of the dome it is simply an extra layer that insures the refractory and steel dome are free to expand and contract independently as they heat and cool. An inexpensive bit of insurance.

Keep us posted as to your progress. I note that there were several months between your initial postings and the most recent with picture. That's unfortunate as perhaps the present circumstance could have been avoided.

Sorry, that I cannot at this point be more helpful,
Wiley

[P712]

Re: Mobile oven design Buoy...HELP

I appreciate the comments. The dome was welded after I gave instructions not to do so; the "friend" was trying to rush the job thinking he knew better. It does seem logical that the heat transfer will be a problem, even after the dome has its insulating layers. What about increasing the fire brick insulating layer from 3 inches up to 6 inches? Would that help keep heat in the oven and off the trailer? Or perhaps building a suspended poured masonry deck an inch or two off of the steel plate? I could weld a rebar frame into (but not attached to) the bottom 3 inches of the buoy steel plate using FB insulation board as the first one inch to keep the masonry deck elevated off the steel deck, then place fire brick deck, thus minimizing the heat transfer from the fire. Though I'm guessing much of the heat will be transferred from the flames rising up to the dome itself and transferring to the trailer.

Or recommendations on a better fix?

[Tman1]

Re: Mobile oven design Buoy...HELP

More insulation in the floor will help, but I don't think that is the major issue. I'm thinking that you are correct and heat will go through the dome and into the trailer. You'd have to put a smaller dome INSIDE the buoy and insulate between the two.
I wonder if the perlite/vermiculite mix is strong enough that you could plaster it on the inside a for a couple inches? Then use insulation blanket, then a new dome? Certainly doesn't sound fun. Cutting the weld while you still can would probably be the best course of action. Although I know you don't want to hear that.

[P712]

Re: Mobile oven design Buoy...HELP

So update...had a smackdown with "friend" and it ended with me hooking up my trailer and drove off huffing. Oh well, friends are over rated. So I set up shop in my Dad's garage. Bought a torch and took the dome off at 5 inches up from weld. Managed to find some fire brick and rented a brick saw from HD for $50, it made fast work of those bricks. My plan is to lay down FB board from Forno Bravo store (2 inches) then lay the bricks on top (3 inches). After that I'm stumped as to connecting the dome back on while keeping it separated from the trailer some how.

[P712]

Re: Mobile oven design Buoy...HELP

sorry those photos are wrong side up

[RTflorida]

Re: Mobile oven design Buoy...HELP

I'm going to side with dmun on the foil, it has been noted on many past threads that cement/concrete (portland cement) is highly corrosive to aluminum foil. In theory, a slip plane seems like a good idea, aluminum foil is not the answer. In no time the cement based product (vermiculite concrete) will be in direct contact with the steel dome, with the vermicrete layer moving with the steel. Many have said that foil is the reason for reduced cracking, science says that other variables are at play, its not the foil.

RT