Guanajuato Build

[UtahBeehiver]

I moved the thread to Pompeii Oven Construction. I should of done this a long time ago, my bad.

[Kvanbael]

The oven looks just great! Creative use of materials, and it looks like your flue heat-break is very thorough. Is that Cal-Sil exposed on the ceiling of the flue?

[Jubilado]

Thanks for the compliment. I'm pleased, but it would be impossible for me to win an oven beauty contest on this forum. There's a lot of gorgeous ovens out there!

The calsil thermal break pieces arch up from the calsil floor insulation to the edge of stainless flue (ID of the flue). The 2" calsil edge is exposed between the inner and outer arches from a couple inches below the stainless flue down to within about 4" of the landing. There is a thin stainless U-channel that protects the calsil near the landing, where I figured it could be subject to abuse. The inner and outer arch break meet the faces of the calsil with slight gaps that are sealed with black high temp mortar (from a caulk tube) against the inner arch and high temp silicone against the outer arch.

This photo hopefully shows it better, in-progress with the flue in a posed position. If I took a photo now you would only see the black soot between the arches.

Rob

[Jubilado]

I came upon this photo of my setup for cutting ceramic blanket, which worked quite well for me. I started with a razor knife but the knife and setup in the photo worked much better.
The ceramic blanket will dull anything in about 2 cuts.
So I took our 'picnic knife' (vintage dollar store) and our sharpener from the drawer. Resharpened the knife every couple of cuts. A sharp knife seemed to create less fibers in the air.
Rob

[Jubilado]

In order to reduce the heat loss from the galley, I folded a couple of fiberglass fire blankets to form a cover, maybe 1/2" thick. They were cheap and easily purchased online. I think it has helped a fair amount with retaining heat in the oven. There is only about a 1/8" break between the oven floor and the galley floor, so it is a major area of heat loss.

[Jubilado]

I haven't yet taken a temperature decay profile. Nonetheless I thought I would post something to show the heat retention character of the design of my oven for anyone interested and thinking about construction.

Thursday evening - pizza with floor temperature about 650F
Friday evening - Baked salmon (mango sorbet/smoked paprika glazed) with roasted asparagus and potatoes at 525-550F
Sunday afternoon - Baked pecan sandies at 325F
Monday morning - load wood in for next fire at 220F

I think I'm getting a good return from the 6" foamglas/calsil floor, 6" refractory blanket dome, 4" door insulation. And then there's eating well and having fun,,.

Rob

[yomer]

I haven't yet taken a temperature decay profile. Nonetheless I thought I would post something to show the heat retention character of the design of my oven for anyone interested and thinking about construction.

Thursday evening - pizza with floor temperature about 650F
Friday evening - Baked salmon (mango sorbet/smoked paprika glazed) with roasted asparagus and potatoes at 525-550F
Sunday afternoon - Baked pecan sandies at 325F
Monday morning - load wood in for next fire at 220F

I think I'm getting a good return from the 6" foamglas/calsil floor, 6" refractory blanket dome, 4" door insulation. And then there's eating well and having fun,,.

Rob

Hola Jubilado,
I hope you're doing well. I'm planning on getting a custom built or precast oven for the house I'm renting. I would love to build my own, but the truth is that I can't get enough free time.

I'm in contact with two contractors. The first one offers me a custom built brick oven and I'm trying to get him to send me a custom quote with my own modifications over his design. I'm looking into adding 2 inches of Foamglas, 2 of solid CalSil, asking for an extra layer of insulation for the dome, a custom built insulated door and the adjustments for a thermal break between the dome and oven floor and the not so deep gallery.

The only problem with this first contractor, besides the higher price, is that I have a very narrow space to bring down the oven to the patio. He cannot build it on site, so it has to be able to be lifted and fitted through a 1.05m wide set of stairs, with a height clearance of 1.40m.

The second contractor is offering a 2 inch precast oven built on site, and I'm in talks to get the same modifications that I asked for to the first contractor. The advantage over the prebuilt is that the precast pieces would definitely fit through the stairs. I would have to deal with getting the oven out of the house a several years down the road.

I think I might be able to get the CalSil board from a local supplier in Monterrey, but I've only gotten a quote from Latin Exports for the Foamglas. I'm hoping to find a local supplier too, to avoid high shipping costs.


My goal is to use the oven primarily for pizza on an evening and still have the 525-550F residual heat for bread baking during the next day, between 18 and 24 hours later. What you achieved on getting those temps one day later is fantastic, I would love to reach that kind of performance, or at least achieving it by 2-4pm the next day. The problem with reaching that goal is that I can't ask the contractor who prebuilds the brick oven to add extra thickness to the dome or more insulation at the hearth because the oven would definitely not fit through the stairs. Then, with the second contractor, the precast is fixed at 2 inches, and the best thing I can do is to get the best insulation possible.

Both oven options would be built for hybrid gas/wood fuel and on a wheeled platform. I still have to get more info on preventing heat loss through the chimney, and any other way possible.

Do you(or anyone who would like to chime in) have any advice or comments on my oven options and how to achieve the least heat loss possible? Thanks.

[Jubilado]

Hi Yomer,

I just noticed your message last night. I don't log on to this site very often now.
I hope things have settled down with the water supply in Monterrey. Sounds pretty horrific. Fortunately, unlike last year, we have had a fair amount of storms and rain drift into gto lately.

If you want to use retained heat you will need thermal mass for heat storage along with good insulation for retention. Your problem seems to be the thermal mass, which you wouldn't get from a 2" thick dome. But you could always add fuel the next day or two.

I don't know how you move a pre-assembled oven, likely weighing a ton, in place without cracks or worse. (Did you say stairs?) If your limited to 41" OD access and the wall is 4-1/2" you will net out at 32" ID max. It seems that the brick would need to reinforced for movement, perhaps further constraining the diameter. So the pre-cast sounds like a better option for construction. It might be feasible to use the cast kit and increase thermal mass by building up the wall with a re-inforced castable mix. I don't know if anyone on the forum has experience with this.

Regardless of brick or cast design, there is completion with insulation, the flue, and finish. Tear-down, disassembly, moving, and rebuilding would be major issues.

You've got a lot of constraints to work with on your oven. If you can handle 2 years of patience you might wait until you shed the space constraints and consideration of moving the oven. I know that there are good number of great restaurants in Monterrey. I would guess, if it were me, likely in 2 years reality would sink in and the oven would be the property of the landlord.

Regarding Foamglas: The folks in Mexico City will ship the foamglas and they say it will stay in-tact. I didn't trust that opinion, so I added the drive to Mexico onto another refractory materials trip to Queretaro. But I don't think there is a supplier of Foamglas in Monterrey, surprisingly - or elsewhere in the country. You'r 2 hours out of Laredo, but the Foamglas suppliers in the US were very expensive for freight. Freight is inexpensive here and you might try to negotiate a guarantee for shipment of the foamglas from Mexico. If you purchase in carton quantities it does seem that some robust packaging would work.

It will be interesting to hear of your progress. Good luck!

Rob