OctoForno

[GianniFocaccia]

Re: OctoForno

Hi Joe,

I didn't mortar the oven/entryway arches together. In an effort to minimize the contact area between the two, I angled the entryway arch bricks so they barely touch. When I get back home I'll post a pic from the outside of the oven so you can see the 3/16" heatbreak gap this created.
I considered doing it the way Colin did his (oasiscdm) but eventually went a different direction. Seeing how nicely Colin's turned out, I should've gone it like his.

Your oven is coming along nicely, BTW.

John

[GianniFocaccia]

Re: OctoForno

Got a fair amount of progress made on the oven over the holiday and happy to report got it fired for the first time.

Finished the vent and although it was tedious to get four curving planes to merge in a trapezoidal shape, I'm satisfied with the way it came out. Got my flue (34?) back from the fabricator and I'm hoping the unrestricted flow and vent depth (7") work well together.

I was able to source 20ga steel studs (local drywall distributor was inexpensive and amply stocked), tapcons, insulating firebrick, three rolls of 1"-thick CF blanket and some Inswool CF caulk.

I've never worked with steel studs previously but found that my angle grinder and a metal cutoff blade worked a treat. It was easy and quick and I did not cut myself once! It also helped to have locking clamps to hold everything in place while screwing in self-tapping screws.

I used the IFB to 'hang' my flue (12ga stainless - 34lbs). All of the flue weight is supported by the studs and the entryway vault is free from any load whatsoever. I used the Inswool caulk to seal the perimeter of the dome/entryway heatbreak as well as the flue/IFB.

Half of the insulating blanket was good for two layers, three in some places. I just wanted to check for any cracks before installing the rest.

My firing schedule was performed with a great deal of anticipation and worked beautifully for the most part. Knowing my oven was completely dry, I heated the oven walls and ceiling up to 300F over the course of an hour, moving the fire from the left side to right. I raised it 100F over the next 30 minutes, then again another 100F the following half hour. I stopped raising the temp once it got to 670F (fire side of dome), 660F (ceiling) and 490 (floor). I am pleased to report no dome cracks!

However...

Upon my initial lighting, I was overanxious to see how my vent performed and had the fire closer to the front than the middle of the oven. The flames (just for a minute) started lapping at the arch and the resultant crack (front and center - where else! ) appeared. This promptly bummed me out, but there?s no one to blame but me. As of this morning it hasn't closed up so maybe I'll try to fill it. There is a tiny hairline crack one brick high behind the offending arch brick, but no other cracks throughout the dome.

When the oven was running comfortably at 550F (no flames licking the ceiling) I baked my first pizza, as promised to my daughter for her help along the way. I would say it came out average, and definitely needs a hotter temp to be called real. One thing I noticed is that the floor took quite a while to come up to temp. I'm guessing that I will need to run an aggressive fire for close to two hours to bring this puppy to full saturation and respectable pizza temps.

An interesting note is that even after two hours of steady firing, the flue never got over 120F. Is this possible? If so, I'm thinking the IFB might have been overkill. Another curious thing that happened was that a sequence of small whirlwinds began dancing around my entryway floor directly below the flue. I'm guessing it was caused by the merging of outside cool air (it was about 6pm) and the oven exhaust heat. Has anybody else seen this? I'll try to post it to YouTube from my camera video.

I'll post some more pics once I get the rest of my enclosure steel erected and concrete board/granite cladding installed. Below is a pic of what its supposed to look like when its completed.

Happy New Year everybody.

John

[SCChris]

Re: OctoForno

Bit by bit, it gets done! Very cool John!

Chris

[UtahBeehiver]

Re: OctoForno

John,

Congrats on the your firing. It has been a long haul for you but you are there now. Look at all the tapered arches you have inspired.

[deejayoh]

Re: OctoForno

Congrats! All first class, as usual.

My guess is that the flue will get much hotter than 120F - especially close to the bottom (my oven is often 600 or higher at the top of the entry arch.) Looks like it is single-skinned, so I think the IFB were a good idea. With a full temp oven, the gasses at the top are probably hotter than 120...

[mrchipster]

Re: OctoForno

Remember you are mixing a lot of outside air with the oven heat as it goes up the flue. I think if you would be measure the temp of the back of the flue it would be hotter. Also the stainless seems to have a reflective surface that does not give a good read with the IR gun.

That floor looks almost to perfect to cook on.

I have seen the vortex in the front of the oven just below the flue. I also experience the clear air below about 8 inches with dense smoke above that.

Beautiful as expected, and congrats on your first fire and food.

Predicted -23F on Monday morning high of -11F and I will be. Smoking ribs in the oven, you can cook all year long.

[oasiscdm]

Re: OctoForno

Hi John

Yay......... Congratulations. Crank it up slowly over a long period you have been patient so far. I've been firing mine since 15.12 only just got to to the roaring point New year's eve.

Personal thanks for your assistance it was fun doing the front entry with you. The angled flue a real b....h

[bodisafa]

Re: OctoForno

Hi John,

I live in Los Angeles and have started building designs for my Pompeii oven. Your build is so inspirational to me.

- Jeff

[GianniFocaccia]

Re: OctoForno

Thank you Russel, Chip, Chris, and Dennis, for your supportive words now and along the way. Colin, I feel like I was there building your oven along with you and confess I like looking at your oven (and the interior colored rings as well as the Yin/Yang plug) the most.

Look at all the tapered arches you have inspired

When I first posted my arch pics I wondered how many builders might follow suit. I was surprised to see how easily many builders jumped right in. Its cool when a simple design change also solves arch placement and dreaded-droop challenges.

Chip - You're right. The 120F was read off the back of the flue, but the fires were probably too small to generate any real heat. I'll test this theory in the next few days, after my crack-repair job has a chance to cure a little. (pics below). I did the repair really quickly (on a warm oven) so won't be surprised if I have to re-do it later.

Every time I look at that pic of the first pizza I think its cooking on a kitchen floor! Weird! I'm curious how hot I can get the floor and really anxious to find out how it performs baking bread once it has been fully saturated and the oven/floor equalized.

Sorry - it has been 75-80F here (82F on Xmas day!) and doesn't feel like winter. The local mountains have NO snow on them which hasn't happened in a long, long time. It must be nice to know that every ounce of insulation you wrapped around your oven pays huge dividends in the worst temps.

Hey Jeff - Welcome to the Forum and if you have any questions on your design, just ask. I can help point you in the direction for local supplies if you want. Be sure to read through the FB Pompeii oven plans (if you want to build a round oven) and plan to over-insulate from the start!

John

[kbartman]

Re: OctoForno

Congrats on firing your oven and cooking that first pizza. Your build is a inspiration to all.

Sorry about that first crack.... although I see you have made the repair. My first crack very similar to yours, happened with those flame lapping out with the fire close to the front. Since then I've been a little easier on heat up. My crack has not grown and has since filled with soot, so I'm not to worried. Hope your repair works and keeps that bugger away........I may try the same.

Ps. My crack is a lot bigger with a greater temperature differential.

[GianniFocaccia]

Re: OctoForno

Thanks KB,

When I looked at the crack the morning after, the mortar kind of just 'fell out' which means I didn't initially mix the home brew very well (at all). During the entire build I usually over mixed my mortar, entraining slit of air into their to ensure all granules were sufficiently hydrated. This small oversight was certainly my fault. Too bad it was front and center. Oh we'll.

Your oven was artfully cobstructed, and to tell you the truth, your crack is barely noticeable. You'll get many, many enjoyable meals out of it. Kudos on a job well done.

John

[kbartman]

Re: OctoForno

Thanks KB,

When I looked at the crack the morning after, the mortar kind of just 'fell out' which means I didn't initially mix the home brew very well (at all). During the entire build I usually over mixed my mortar, entraining a lot of air into the mix to ensure all granules were sufficiently hydrated. This small oversight was certainly my fault. Too bad it was front and center. Oh we'll.

Your oven was artfully cobstructed, and to tell you the truth, your crack is barely noticeable. You'll get many, many enjoyable meals out of it. Kudos on a job well done.

John

Thanks for the complements on my build.....My crack is a lot more noticeable on heat up. I used a pre mix refractory mortar on my. I tried to shoot for 1/8" mortar joints, that was quite a challenge on the arch I ended up with very little mortar in my top joints. Oh well water under the bridge.

I think I may have over mixed the stucco I did recently on the enclosure. The manufacture of the stucco cement stated to mix a min of 5 minutes. I had some adhesion problems. I thought the more the better. I wonder what the max mix time would be? I hope I don't have the same issue when I stucco the rest of my build. I notice a slight bow on one of my walls I hope it not hollow underneath. No cracking yet, I will have to drill a small hole and check for a void.

[GianniFocaccia]

Re: OctoForno

Not really experienced with stucco altho I like the look. I'm sure there are others here who can offer advice.

[stonecutter]

Re: OctoForno

I'm looking forward to seeing the granite cladding.

[Tscarborough]

Re: OctoForno

Whenever you are mixing stucco or mortar, if doing it by hand, a minimum of 5 minutes is really a minimum. It goes through stages, depending upon how you add the water.

I add about half the water that I think will do to one side and then mix that into a slurry, then begin mixing in more dry material, still keeping the mix soupy. Once there is no more free water, begin adding small increments of water, mixing the whole mass together before adding more. When it is 100% mixed, no dry particles, evenly "wet", let it rest for a few minutes, then mix it for another minute or two and it is ready to go.

Hey! That is exactly the way to hand mix dough too, who would have thought....