firing a wet oven

[paulages]

i fired my oven up yesterday (sorry, no beer yeast dough) for the first time in a few weeks. though i've kept it covered with a tarp, rain was bouncing in the opening off of the shelf in front. i fired it a couple of times just to try and keep it dry, but it inevitably had moisture in the floor bricks.

you could actually see moisture evaporating from the floor bricks in the intake path at the entrance. vapor was rising off of the bricks and sucking into the fire. i couldn't get the floor above 450 F, despite a roaring fire. it's at about 120F now, 15-16 hours later, which has kept the torrential rain all night long from wetting the floor where it came in through the chimney.

i'll post how many fires it takes to get up to proper temp. once it gets there.

[james]

Paul, do you have door? Also, looking at your chimney, I didn't see your cap/spark arrestor. Having those will help a lot. In a perfect world, the inside of your oven won't see moisture, other than what it wikes out of the air.

Whadya think?

James

[vitoduke]

We fired our oven on Saturday after 2 days of light rain. I built the fire slowly over 3 hours and did not notice any steam on the inside or outside. This was our first fire after a rain, and maybe our waterproof stucco actually works. The oven had no trouble getting up to temperature. ---Mel

[paulages]

you're right james. i have no chimney cap yet. i was keeping a piece of tarpaper over it, but i added the other piece of chimney pipe yesterday to cook, and then left for the evening. i didn't expect last night's downpour, but like i said, retained heat seemed to keep that bit of rain coming down the chimneyfrom soaking in.

no, i have no door yet, but the biggest problem was having no overhang above the door. i now have rain cover from my back door to the front of the oven (about 8' distance), so it shoudn't be an issue, once i get a cap/spark arrestor on the chimney.

[binkchad]

Gents -- Being new to the forum experience, please excuse my ignorance of where you are in your oven building. Are there picture links somewhere? I'd love to see what you're talking about. My husband & I put the insulating castable on our "Superior" oven Sunday (with help from the neighbor's 5-year-old son.) How do you know when it is dry? Can you point me to more info on this here?

Thank you,
Chris

[paulages]

here's the link to the thread showing my pompeii in progress:

http://fornobravo.com/forum/showthre...&page=16&pp=10

[dmun]

Superior entrance

Tell us more about your "superior" oven. Is that Superior Clay Co, that make the rumford fireplace throats?

http://www.superiorclay.com/oven/index.htm

I ask because it doesn't look like one of theirs. It looks like your oven entrance is made of a section of refractory clay tile, which I think is really clever. Oven builders here have been fighting the dome/entrance interface issue, and this seems like a simple, solid, strong solution.

David

[binkchad]

Yes, we have a 24" Superior Clay Bake Oven. This is our first oven plus we don't know anyone who has built an oven, so I can't tell you too much about it other than it has come together very easily and has been a blast to build. Their website has detailed pix that show the dome/entrance pretty clearly. The 36" oven is completely different. http://www.superiorclay.com/oven/oven24.html

It's quite humbling to see the masterpieces that folks on this site have built.

Here's our series of photos ... so far. http://www.cchadwell.photosite.com/C...low/TheFooter/
(Click on View Slideshow & then with the slide on the bottom right you can speed up the show.)

[binkchad]

here's the link to the thread showing my pompeii in progress:

http://fornobravo.com/forum/showthre...&page=16&pp=10

I'm looking forward to seeing what you do next. We plan to build the box around our oven very similar to yours. Same roof line. I'm visualizing "Florida Cracker Shack" with wood siding (Hardieplank) on the bottom, brick on the top & a tin roof.
Chris

[paulages]

i thought about using cedar shingles on the three sides away from the door, to match the building behind it, but decided that i prefer the all masonry look instead. i would have prefered a gabled roof, but i really wanted a "living" roof, which seemed easier to do as a shed style roof. i also like the style of a stone shed structure. the living roof means less water runoff (what isn't a building or garden on our little 100' x 50' city plot is paved or flagstone), which is important in my rainy climate.

[dmun]

tile entrance

Everyone should go look at these pictures. They are full of good ideas for the oven builder.

I like how the rebar for the floor is tied to that in the filled block corners, should be really strong. Notice how, too the insulating layer is on top of the support layer.

The flue tile entry is a way clever idea. It involves some serious diamond cutting, but it looks really strong, and avoids iron supports with their expansion and corrosion problems. One big cut (and a potential for weakening) could be avoided if you embeded the bottom of the flue tile in your insulating concrete, and built the floor out inside the tile.

The conventional wisdom around here is that 24 inches is too cramped a size for fire-in-the-hole pizza making, but lots of people want a smaller oven, and the ideas could be upscaled for the home builder.

Good work!

David

[james]

Hi Chris,

Nice work. You are really going to enjoy having it.

Can I ask a couple of questions?
What is the material in the castable that you used to cover the oven. Is it an insulator? Also, are you planning on adding additional insulation between the oven dome and the upper walls. I always think that insulating the heck out of your oven really helps -- particularly with smaller ovens, where the opening is a higher % of the volume of the oven chamber itself. Basically, a well insulated oven works better. :-)

Enjoy the finish, and look forward to that first pizza.

James

[binkchad]

Paul -- We too have a 50 X 100 city lot which is why we ended up with the smaller oven. When my husband first mentioned building a pizza oven & we started our research, the size of them made me nervous. I was worried about the proportions compared to the rest of the structures on our lot -- plus getting it past the Historic Preservation Board.

Is a "living" roof what I'm guessing it is? You actually have something growing on top? If so, that is an incredibly cool idea! Not something you see here in the subtropics, except algae.

David -- Thank you for your kind words. My husband epitomizes Paul's quote: "overdo it or don't do it at all!" This goes for garlic, chile pepper, tieing knots & tightening screws too.

James -- The insulating castable came with the Superior kit. Two 35# bags. It doesn't say on the bag what they contain (except the cancer causing crystalline silica) but they're produced by Mt. Savage Specialty Refractories in Pittsburg. Based on the 6:1 mix of Vermiculite:cement we used on the hearth insulation, I'd guess that it has more cement & maybe fire clay.

Yes, we do plan to do more insulating. The kit came with two bags. One gave us a generous 2" cover. We also have five 15# bags of vermiculite to fill between the dome & upper walls.

Which leads me to my next question. Since we have that other bag of insulating refractory left, would you thicken the dome covering? (Keeping in mind we'll use the 5 bags of v-lite.) Or would that be "overdoing it"?

Thank you all for allowing me to pick at your knowledge!
Chris

[james]

Chris,

While I would normally say that there is no such thing as too much insulation, you have a finite amount of space between your oven and upper enclosure walls -- so the goal should be to fill that with the most efficient insulation.

If we were to guess that the castable was an insulator, combined with Portland, then loose vermiculite should be more efficient.

Would everyone agree with that?

If you want to push the boats out, your could buy Insulfrax, which is about twice as efficient as vermiculite, but more expensive.

Another option would be to use the extra castable on top of the oven, where you have more space to work with.

James

[binkchad]

Is a "living" roof what I'm guessing it is? You actually have something growing on top? If so, that is an incredibly cool idea! Not something you see here in the subtropics, except algae.

Paul -- Disregard that question. I finally read [most] of your Pompeii in Progress post & am now more curious than ever about your living roof. Looking forward to seeing those photos. I also want to compliment you on the work that's happening in the background. What a beautiful transformation!

James -- That's good news -- I frankly didn't want to wait for more cement to dry!

So what CAN we do with that extra bag of insulating castable? (Correction, the kit came w/ four bags not two.)