The All Solid-State Oven

[james]

I've been thinking about insulation, footprints and water, and I am starting to lean more toward the solid-state oven. Insulfrax above and SuperIsol below, and not a grain of Vermiculite to be found. That is the basic design of our assembled commercial ovens made in Modena, and it makes a lot of sense, both from a heat efficiency perspective, and from an ease of installation perspective (nothing to mix or pour).

There is always a great deal of customization and personalization regarding oven installation, either the Pompeii Oven or a Forno Bravo modular oven, but FB.com can give direction and open the discussion.

What do you think? Recent builders? Folks considering installing an oven?

Anybody want to jump in with Pros and Cons?
James

[CanuckJim]

Re: The All Solid-State Oven

James,

The solid-state idea is attractive because it is easier, less complex, less messy, etc., etc. Could we get a few comparisons? What, is the heat stopping/retention of 4" of Insulfrax versus 4" of a vermiculite/Portland mix. The same comparison of SuperIsol versus a traditional vermic/Portland insulating layer would be helpfu. I'm definitely leaning in the solid-state direction, but some clarification would be helpful in making a decision.

Going solid-state, all other things being equal or better, would be wise because the overall weight of an installation (particularly an inside installation) would, I think, be greatly reduced. Using a steel stand would further reduce weight.

Jim

[jwnorris]

Re: The All Solid-State Oven [Casa110]

This is exactly what I did this summer/fall. A FB Casa110 is in the corner of a BBQ island that is along a wall of my side patio, flanked by a 36" gas grill and a double burner.

BBQ island fabricator built a stand out of welded square steel tubing [with a center support]. The sides and the top have a covering of cement backer board.

A 2" slab of SuperIsol covers the top. The sectional floor was dry laid on the top. Next, I set the dome on the base and sealed the exterior joints with a 2? layer of Refrax mortar. Only the best California earthquake will disturb this installation.

An 8" douoble-walled SS vent rises six feet and draws well. Then the entire dome is covered with 2? of Refrax. This is followed with 2 to 3 layers of Insulfrax insulation blanket. The dome is then covered with black paper, wire and two coats of stucco.

While this could have been accomplished in three to four days, it took me several weekends. I haven?t painted it yet and wonder if I should use some sort of waterproofing first.

There are a couple of spots toward the back of the dome that get warn to the touch and a few hairline cracks in the stucco. The cracks disappear when the oven is cool, although there is a large crack in the front where the stucco meets the front of the modular casting that forms the door opening ? this has NO effect on the performance of the oven.

It cooks great, pizza and other dishes, and I hope to try bread next. A Tuscan grill is in route.

J W

[tommy5]

Re: The All Solid-State Oven

my casa 100 has about 1 inch of refrax, and 1.5 rolls of insufrax, plus a couple of bags of vermiculite, before i secure the roof is this too much? too little?

[dmun]

Re: The All Solid-State Oven

Some quick ideas here: in the no mix or pour department (I'm sounding like a broken record on this) Why doesn't FB import and sell those strong cheap lightweight terra cotta lintels that the Italians use under ovens?


Lifting buckets of concrete is no fun.

And how about curved blocks of super isol or other high tech insulator to make rigid dome shapes?

[james]

Re: The All Solid-State Oven

Tommy,
You are in great shape. There's no such thing as "too much insulation." Do you ever feel any heat on the outside of the enclosure?

David,
The terracotta lintels are great (no mixing!), but I'm concerned about how much they would cost by the time they arrived in your backyard. They are very cost effective here, but with importing and shipping around the states, they could end up being expensive.

What do folks think? I would do more research.

For the over oven insulation idea, I know of one pizza oven company that mixes and pours a castable insulator around the dome for their assembled oven, but that doesn't make sense to me (other than saving them money). Insulfrax is so efficient and easy to install, that I am coming to like it more and more. Throw in the cost of vermiculite, the hassle of finding it, the labor/cost of mixing it -- and you might be better off with three layers of the blanket.

For more context on that, there is a U.S. pizza oven company that wraps commercial ovens in about 3" of woven insulation. That's it. Your backyard oven will be fine at that thickness!

On the efficiency question, Jim -- the high tech products are both about twice as efficient. 3" Insulfrax replaces 6" Vermiculite, or 1" Insulfrax and 4" Vermiculite over the dome. 2" of SuperIsol replaces 4" Vermiculite under the cooking floor. The high tech insulators don't cost that much more than Vermiculite and you can always go thicker (to be over-safe).

Lot's for future builders to think about -- but it's all good news.
James

[jwnorris]

Re: The All Solid-State Oven

It has been a bit brisk here in SoCal however, I don't think that it is ever too cold here to fire up the oven. And that's just what I did on Saturday.

While not so much because it is a solid-state oven, I am finding that if I let the oven get saturated with heat [going 30 to 45 minutes past the time it is up to temperature] I am cooking more consistently and enjoying it more.

I spent a little more time checking over the exterior of the oven this time than I have in the past. I do not feel any heat getting through the 2" of SuperIsol [and 1/2" of cement board] that make up the base of my oven.

There are only a couple of places on the dome that are even warm to the touch. These are in areas that I remember having 2" or so of InsulFrax blanket as oposed to the majority of the oven having 3" or more [more due to some overlapping]. The area on the side where the fire was banked was still cool to the touch.

Esepcially for a igloo housing, I feel that the solid-state concept is the way to go.

J W
Casa110