Thin walled Barrel Vault on wheels

[okn]

So I finally started my build. It is an extreme deviation from the plans. As a matter of fact it is a complete deviation from the plans with the exception that it is/will be fairly well insulated. Basic design considerations was I wanted it to fit through my garden door if I ever wanted to sell it. That also meant I would have to be able to move it, to get it through the door. So I decided on the following design ?features?:


1. It will have wheels
2. If it has wheels it should have a metal base
3. should be no more than 34.5? wide so it can be rolled through the door
4. If it is going to be mobile, it should be relatively light
5. Budget not to exceed 1K USD in materials


So using these basic tenets, I thought the best use of real estate would be a barrel vault. Also the barrel vault builds tend to be faster. Considering the design limitation of 34.5? wide, I decided to make the oven a bit wider the deep. I will be using 3? thick INSBLOCK 19 on the floor and sides. I will keep the wall, dome, and floors at 2.5? thick. To help keep things light, I will not have a concrete hearth, I will lay the insulation directly on the metal supports.


So here are pictures of the stand I welded up two weekend ago

[okn]

Re: Thin walled Barrel Vault on wheels

The insulation (3? thick INSBLOCK 19) is laid directly on the frame. I actually used that sheet metal screen in between the supports and the insulation. I thought it was a good idea when I was ordering the metal, but I personally wouldn't do it again. I don?t think it adds anything.


So on Friday I got the floor laid used the herringbone pattern as recommend by so many on this forum.


I started dry laying the walls, which are outside the floor area. The entire oven will be only 2.5? thick.

[okn]

Re: Thin walled Barrel Vault on wheels

Saturday, used the chain to find the catenary arch, built the form, then cut them into three pieces so I could get them out.

Started cutting the fire brick and dry fitting everything.

[okn]

Re: Thin walled Barrel Vault on wheels

Sunday, starting mudding everything together. After I got the dome finished I was so proud and took the frame out. I believe this to be a BIG MISTAKE. I would wait a few day for it dry if I have to do it again.

Next up was the door arch and bricking in the front wall.

Well, the good news to all this is the entire dome was built in one day. The bad news was that when my friend and I were cleaning up, we rolled the oven to side and it got all cracked up :-( So that definitely is a NO GO - BIG MISTAKE- for anybody looking for advice or lessons learned. Seriously, I was all delighted when that thing went up so fast I felt indestructible my self, but that changed in about 2 seconds when I saw the cracks. To try and mitigate the cracking, I sprayed the top with a little water and we tried stuffing mortar into the cracks, and propped up a couple of ?sliding? dome bricks. So the worse case is I have to knock down the dome and build it again. If I do that, I will taper all the dome bricks (only 27). I?ll be letting the oven dry for a few days, while I add the insulation walls and weld the pertinent reinforcements to contain the arch forces and the insulation. I plan to start curing fires next weekend, with first pizza being cooked the following weekend.

[WJW]

Re: Thin walled Barrel Vault on wheels

I admire the speed and ambition...but I'm afraid it may be too ambitious.

There are many (most) here who know more than I, but my fear is that by stacking the bricks on their narrow side, you so significantly reduce the bonding surface that you weaken it tremendously. Then to compound problems, you have it on a cart where stresses from movement make things even worse. I hope I'm wrong, but I suspect that this combination might be insurmountable with normal building materials/methods. It seems to me that thin walls and mobility may only work with a castable refractory with lots of stainless needles for support. (But again...I don't really know.)

Hopefully you can repair the damage, let cure, and then move it as little as possible. But if it were me, I think I'd try to come up with a cart that could take the weight of bricks bonded on the big side.

Bill

[Les]

Re: Thin walled Barrel Vault on wheels

Where is the vent? Or is the design to have the smoke/hot gasses exit in your face?

EDIT... I assumed this was for pizza and baking, if it only for baking then my above comment is moot...

[okn]

Re: Thin walled Barrel Vault on wheels

Vent and landing will be metal and bolted on. Should have something by next weekend.

Bill, I think you're right LOL, will probably be rebuilding soon. Then again, there's really no where for the bricks to go.

[WJW]

Re: Thin walled Barrel Vault on wheels

Yea I get that it's encased. I just question the ability of bricks/mortar to take moving around on a cart....but again... honestly don't claim to know for sure.

As far as the bricks having nowhere to go...I get the irony and how many times I've said that to myself....I just hope it's correct for both of our sakes.


Bill

[david s]

Re: Thin walled Barrel Vault on wheels

Some pneumatic wheels on the stand will make a big difference to moving it safely.

[Tscarborough]

Re: Thin walled Barrel Vault on wheels

A couple of things. First it is not a barrel vault, it is a low dome square oven (just semantics). Second, you should put a (1/2-3/4")layer of refractory over the entire dome to act as a bonding skin. Third, you should offset the door on the next iteration.

My next oven will be similar in style, i.e. low dome and almost square, so I am curious to see how well yours draw.

[stonecutter]

Re: Thin walled Barrel Vault on wheels

You did yourself a favor by bonding your arch bricks together, instead of doing rows of single arches.

[okn]

low dome [almost] square oven on wheels

Sounds like "(1/2-3/4") layer of refractory over the entire dome" it is.

Tom, I hope you?re talking about homebrew refractory, because that's my plan for tonight.

David, I have some wheels mounted. They are 3" metal, with a load capacity of 1000 lbs. each. Looked at the rubber wheels, but decided that because of long periods of inactivity they wood probably not be the best choice. If I were planning on moving it quite a bit, definitely would have sent the extra cash for them.

Bill, I'm not too worried about it falling or cracking. If it does I will just rebuild. The stand is beefy enough for much more weight (after I finish adding the diagonals) and firebrick is relatively cheap, so no worries there. I?m just slightly afraid that a brick will land in my pizza!

Kevin

[Tscarborough]

Re: Thin walled Barrel Vault on wheels

That is the ticket.

[WJW]

Re: Thin walled Barrel Vault on wheels

Cool...looking forward to seeing how it turns out.

One thing I'm curious about and would love to hear others respond to...

Is it worth laying hardware cloth (or chicken wire) over the bricks along with the additional refractry to provide a reinforced skin?

Seems like it would provide a substantial amount of strength with very little downside???

Bill

[V-wiz]

Re: Thin walled Barrel Vault on wheels

I say congratulations, keep it up and move on. This thing took you one day to build? even if it were to collapse in the next year its still worth it. You can rebuild it again. lol.