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36" Corner Build in Minnesota

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  • MnDude45
    replied
    Mr. Slowhand - Sad that you had that happen but grateful you were able to catch it at this time rather than later. Keep moving forward, Marko. You are making great progress.

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  • Mr. Slowhand
    replied
    Originally posted by MnDude45 View Post
    Mr. Slowhand - It did not work out well on mine. The hairline crack didn't show the issues through the arch. When I removed the arch form, the arch came apart in pieces. Hopefully, you will not experience the same. Overall, I only lost about a day and a half it it appears to be strong now. Good Luck!
    He, was just clearing to fill in some cracks, when entire actually the entire arch was loose. It came in 2 pieces. I still have the arch form, so cleaned it, soaked, and re-mortared it. So glad you told me what you did, so I checked for structural integrity before I continued.
    Only one evening lost, TBH, not a biggie

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  • Sixto
    replied
    Originally posted by MnDude45 View Post
    ..... I need to remove the pop-up to run the fires but don't want to leave it uncovered for a week.

    I thought I'd insulate and then build the walls of the enclosure to allow a tarp/cover during the night.
    I like that idea, hadn't thought of removing the pop-up myself (tent on fire!)and I have no permanent surround planned. When my time for drying fires comes, I'll lash some 2x2's together to make a teepee of sorts using the tent-top over the dome (but not over the flue) to make sure any water sheds off it, instead of pooling on top.. thanks!

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  • MnDude45
    replied
    Originally posted by james View Post
    Curing your oven is an important step in the installation of any brick oven -- whether it is a Forno Bravo precast oven, a Forno Bravo Artigiano brick oven, or a Pompeii brick oven. Heating up your oven too fast can lead to cracks. You have invested a great deal of time, money and energy in your oven, so go slow, and cure your oven properly. If at all possible, don't schedule a pizza party the weekend your dome is finished.

    After you have installed your oven, there is still a great deal of moisture in the mortars, hearth concrete, vermiculite, and the oven chamber and vent themselves. Each of these oven components was recently produced using an air-drying, water-based process. Simply letting the oven stand for a week does very little to "cure" the moisture out of them oven. In fact, the Forno Bravo precast oven producer recommends letting the oven stand for a week after it has been assembled before "starting" the curing process. Thicker sections of concrete can take many weeks to cure.

    You are trying to avoid two problems. First, any mortar or concrete that dries too fast shrinks and cracks. These cracks can let hot air and/or smoke escape from the oven chamber. Second, if you bring your oven up to heat while there is still sufficient moisture in the oven dome or mortars, you will actually create steam, which can produce hairline fractures, or even cracks in your oven. I heard a story (possibly an urban legend) from one of our installers who used to work with one of our competitor's ovens, where the home owner lit such a large fire in a non-cured oven that a chunk of the oven dome actually blew out the front door. Hmmm. Maybe.

    Also, using a space heater can help, but only so far. It is not an alternative to fire curing. We ran a space heater in an assembled Forno Bravo precast oven for two days, then quickly heated the oven up, (don't do this at home -- it was an experiment to see what would happen to an oven that we have here) and we found that we created a very large amount of steam from the oven, mortars and vermiculite, which went on for hours and hours.

    To be safe, here is a good curing schedule.

    1. Let the oven sit for a week or so after you have finished the dome.
    2. Run a series of seven fires, starting with a small, newspaper-only fire.
    3. Increase the size of the fire each day by about 100F
    200F
    300F
    400F
    500F
    600F
    700F
    800F
    4. Let the oven fall back to cool as soon as you reach the temperature you want. It is important to bring the oven up to heat gently, then back down to cold, each time.
    5. If you don't have an infrared thermometer, try this schedule:
    Newspaper only
    Newspaper and a little kindling
    1 stick of 2"x3"X16" wood
    2 sticks of wood
    3 sticks of wood
    4 sticks of wood
    5 sticks of wood

    James

    Also, here is the firing post from several years ago...Any other suggestions from the group??

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  • MnDude45
    replied
    Thanks for your thoughts. I liked the thought of the galvanized flashing under the cement board. I hadn't thought of that.

    What are your thoughts on how to protect the dome during the curing fires? I need to remove the pop-up to run the fires but don't want to leave it uncovered for a week.

    I thought I'd insulate and then build the walls of the enclosure to allow a tarp/cover during the night.

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  • Sixto
    replied
    Originally posted by MnDude45 View Post
    Alright, I'm planning on building the enclosure around my oven on the concrete countertops. Steel framing with 1/2" Durock cement board with Rock-on fastners.

    Questions -

    1) For the framing track on the countertops, is there a vapor barrier or concrete adhesive placed between counter and track? Typically what I see is some sort of compressible foam or a few beads of caulk to keep moisture from seeping in at the base. If your studs can be flush with the edge of the counter, I would extend the durock to the bottom edge of counter slab, and seal the edge with caulk. If not, I would add galvanized flashing at the base of the durock, so if any snow piles up against it, it has to climb 4-6" up the back of the durock to make it into the enclosure.
    2) I'm assuming stainless steel anchors to hold track against counter I agree.
    3) The most common widths of framing is either 2.5" or ~3.5". Does is matter for this application? I would think this is small enough that 2.5" wall studs should be enough, but I'm not a structural engineer and overbuilding won't hurt.
    4) The most common gauges found at Big Boxs are 20ga or 25ga. The 25ga at Menards says "For interior, non-weight bearing walls". Do I need to ensure galvanized and use a 20ga or possible 18ga? For sure Galvanized studs, othewise they will rust. Gauge, I'm not sure.

    I'm planning on placing the 3" of fiber blanket this weekend and start curing fires but need the enclosure to be fast follow to keep it dry.

    Thoughts??
    Comments in red above.

    Leave a comment:


  • MnDude45
    replied
    Alright, I'm planning on building the enclosure around my oven on the concrete countertops. Steel framing with 1/2" Durock cement board with Rock-on fastners.

    Questions -

    1) For the framing track on the countertops, is there a vapor barrier or concrete adhesive placed between counter and track?
    2) I'm assuming stainless steel anchors to hold track against counter
    3) The most common widths of framing is either 2.5" or ~3.5". Does is matter for this application?
    4) The most common gauges found at Big Boxs are 20ga or 25ga. The 25ga at Menards says "For interior, non-weight bearing walls". Do I need to ensure galvanized and use a 20ga or possible 18ga?

    I'm planning on placing the 3" of fiber blanket this weekend and start curing fires but need the enclosure to be fast follow to keep it dry.

    Thoughts??

    Leave a comment:


  • Mr. Slowhand
    replied
    Originally posted by MnDude45 View Post
    Mr. Slowhand - It did not work out well on mine. The hairline crack didn't show the issues through the arch. When I removed the arch form, the arch came apart in pieces. Hopefully, you will not experience the same. Overall, I only lost about a day and a half it it appears to be strong now. Good Luck!
    Good info. I wanted to keep the arch form, as I am casting a flue shortly. With this info, I will first remove the arch, see if the thing can stay on it's feet, and than put the (smaller) arch form for the sand mould back. You are right, a day and a half are not a big issue when building these things

    Leave a comment:


  • MnDude45
    replied
    Mr. Slowhand - It did not work out well on mine. The hairline crack didn't show the issues through the arch. When I removed the arch form, the arch came apart in pieces. Hopefully, you will not experience the same. Overall, I only lost about a day and a half it it appears to be strong now. Good Luck!

    Leave a comment:


  • Mr. Slowhand
    replied
    Originally posted by MnDude45 View Post
    Alright, I know all ovens have cracks but…

    I noticed this hairline crack in the outer arch. It’s directly in the middle on the last brick I laid. It runs 2/3 down the front and all across the top. It doesn’t appear noticeable in the back (chimney vent).

    Should I be concerned enough to remove, replace the brick and re-mortar before the removal of the arch form? Or just fill and move forward??

    Thoughts??
    I have the same in my oven. I used a scalpel to remove as much as possible of the mortar, and will add new mortar. It was directly next to the keystone of the arch. Don't know if it was a good thing to do, I just could not bear to see it, it is the only exposed arch towards the outside

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  • Sixto
    replied
    I got 1/4" x 3" s.s. bolts at my local Menards. Using lockwasher on top, recessing bottom of bolt in mortar-filled part of brick, so it won't turn when I tighten bolt down. Will cast a sloped cement cap with fiber reinforcement over the whole thing to shed water and snow.

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  • MnDude45
    replied
    Sixto - What size diameter SS anchors are you using? The specs say to use 1/4” but I can’t seem to find any SS in that size.

    On the vent, as you can see in post 173 I placed the front and back arched pieces first and let them set. Then I I cut the interior bricks to size using a cardboard template and mortared them together before placing them on the arch. I cut a notch to rest on the arch with mortar and supported it with a scrap 2x4 until set. Then I did the same on the other side. It looks like you did some nice shaping of the bricks for yours.

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  • Sixto
    replied
    Originally posted by MnDude45 View Post
    Sixto - Thanks for the comments. Regarding your questions:
    "
    1) I'm using the Duratech double walled system with a 10" anchor plate.
    2) I plan to wrap with 3" fiber blanket and build an enclosure with steel framing and cement board so the dome will not be directly exposed to the Minnesota seasons.
    3) I learned the hard way on the outer arch. I built the arch in one day working from the outsides to the top of the arch.
    Thanks Chris! I am using the exact same Duratech system, and thought about using screws, but changed to SS bolts after reading comments similar to David's previous post. I'm not sure how Tapcons work, but if they oxidate, and you cant get them in S.S. then I would perhaps try pre-filling the hole with high temp silicone or adhesive and install the screws into that while wet, so there's less chance of moisture finding its way into the space between the screw and brick.

    You are doing it right with the enclosure. I have a relatively small backyard, and I want to keep the dome visible, so I'm left figuring out how to protect it, both this winter with stucco only, and also after I add tile. Right now, I'm thinking of using some sort of vapor-permeable, waterproof coating on the stucco, then adding a tarp above that.

    Regarding #3, I was asking more about the 10 bricks that make the transition between the arch and the square chimney. But I see in one of your photos that your opening for the anchor plate is square on the inside too, so your 6 bricks in the center are not cantilevered out into the opening... I'm doing something slightly different, and when i set my 12 bricks on top of the arch, the 4 bricks that cantilever in the center, tend to tip into the opening...so I'm thinking of mortaring pairs together before setting them on top of the arch, and also adding support sticks below so they have a chance to hold each other up better. Attaching photo to help visualize...

    Click image for larger version

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  • david s
    replied
    Heat and moisture together will accelerate rusting so any fixings should only be stainless.

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  • MnDude45
    replied
    Sixto - Thanks for the comments. Regarding your questions:
    "
    1) I'm using the Duratech double walled system with a 10" anchor plate. My plan is to attach with hi temp sealant and anchor with four 1/4"x4" Tapcon anchor screws. I have a Tapcon 3/16" carbide tipped concrete bit for the anchor holes. My biggest fear is cracking the bricks of the vent.
    2) I plan to wrap with 3" fiber blanket and build an enclosure with steel framing and cement board so the dome will not be directly exposed to the Minnesota seasons. I'm currently debating the running of the curing fires before or after the insulation. This is a very hot topic for many out here. If I run the curing fires before insulation, I take the risk of the extreme temp changes during curing with the risk of cracks. If I wait until after insulation, I think I may need to build the enclosure to protect from weather.
    3) I learned the hard way on the outer arch. I built the arch in one day working from the outsides to the top of the arch. When I got the the final 2-3 bricks, I put pressure on them to get them into place. When I did this, bricks in the middle of both side of the arch raised and became unset. When I removed the form (as outlined in posts 166-168), the arch collapsed. When I rebuilt the arch, I completed the 1st five bricks on each side and let it set. The next day I set the next three bricks on each side and let them set. The final day I spent cutting and placing each of the remaining four bricks with a cross support to finish the arch. It has held thus far with now the weight of the chimney vent with no cracks that I can see.

    That's probable more than you wanted to know but let me know if you have any other questions or comments

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