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  • Sixto
    replied
    Thank you for the info about crushed or pulverized limestone, Gulf! I confirmed that was the case by looking up the manufacturer's data sheet https://www.midwestmanufacturing.com...SMortarMix.pdf
    I will return the remaining bags and get the right basic ingredients in the spring. Sill have a couple of days over 50 degrees forecasted, so I will try to fill the bond beam at the top of the wall with core-fill before putting away the trowel for the winter.

    Sixto

    Originally posted by Gulf View Post
    Another word of caution. Most bagged mortars do not contain very much hydrated lime for that part of the recipe. The original formulas for masonry cement from which mortar is made has changed over the years here in the U.S. The change has been in the hydrated lime content. Lime was in the original recipe to increase the mortars workability. Since it was highly irritating to human skin the industry has allowed much of the lime content to be replaced with an 'equivalent" amount of crushed limestone and some other proprietary additives. It is still just as good or better for general brick laying but the "equivalent" is not good for our purposes. Crushed limestone does not react the same way as lime when heated. It swells!

    There are very few companies that bag the original formula with hydrated lime so be careful. As for as the sand content is concerned here is the mix for the two most common bagged mortar types.

    Type-N: 1 part Portland, 1 part lime, 6 parts sand.
    Type-S: 2 parts Portland, 1 part lime, 9 parts sand.

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  • Gulf
    replied
    Another word of caution. Most bagged mortars do not contain very much hydrated lime for that part of the recipe. The original formulas for masonry cement from which mortar is made has changed over the years here in the U.S. The change has been in the hydrated lime content. Lime was in the original recipe to increase the mortars workability. Since it was highly irritating to human skin the industry has allowed much of the lime content to be replaced with an 'equivalent" amount of crushed limestone and some other proprietary additives. It is still just as good or better for general brick laying but the "equivalent" is not good for our purposes. Crushed limestone does not react the same way as lime when heated. It swells!

    There are very few companies that bag the original formula with hydrated lime so be careful. As for as the sand content is concerned here is the mix for the two most common bagged mortar types.

    Type-N: 1 part Portland, 1 part lime, 6 parts sand.
    Type-S: 2 parts Portland, 1 part lime, 9 parts sand.




    Leave a comment:


  • Sixto
    replied
    Originally posted by david s View Post
    That would work if you knew the exact proportions by volume, of the ready mix mortar. You are assuming it is in the proportions of 3:1:1 sand, cement, lime. As mortar is usually weaker than that, more like 10:2:1 and who knows what else they throw in, you could end up with a mix that might not perform as it should. If you call the manufacturer they may be able to help.
    Great suggestion, makes sense to confirm the ratio of sand, cement and lime, and adjust them too if necessary. We'll see what I can find-out!

    Thanks, Sixto

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  • david s
    replied
    "I do have one question for those that have used homebrew refractory... I ended up with 3 bags of ready-mix mortar that I'm keeping dry till next year...Assuming it's a 3:1:1 mix, can I add 1 bucket of fire clay for every 5 buckets of ready-mix and end up with a workable refractory? (theoretically that would give me 3:1:1:1 for sand, cement, lime and clay). I have not come across any references to people adding clay to ready-mix grout so far..."

    That would work if you knew the exact proportions by volume, of the ready mix mortar. You are assuming it is in the proportions of 3:1:1 sand, cement, lime. As mortar is usually weaker than that, more like 10:2:1 and who knows what else they throw in, you could end up with a mix that might not perform as it should. If you call the manufacturer they may be able to help.

    Leave a comment:


  • mongota
    replied
    Free advice from the neighbor? NOTHING is free! Next time, charge him if he wants to give you advice. lol.

    Process looks terrific. A great project for you and your son to build now, and enjoy later.

    Leave a comment:


  • MarkJerling
    replied
    Well done Sixto. Looks good!

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  • Sixto
    replied
    I made a form with 2x4's to locate the vertical re-bars and placed (fiberglass reinforcement rods in the holes, had to use a mallet to pound them into the still-wet concrete, to get around a few horizontal bars that were in the way... And started laying block (be easy on my masonry skills, I'm learning as I go....) at least it's fairly level. I'll fill the cores that have rods in them, and seal the open cores with plastic to prevent any issues with ice over the winter...5

    I do have one question for those that have used homebrew refractory... I ended up with 3 bags of ready-mix mortar that I'm keeping dry till next year...Assuming it's a 3:1:1 mix, can I add 1 bucket of fire clay for every 5 buckets of ready-mix and end up with a workable refractory? (theoretically that would give me 3:1:1:1 for sand, cement, lime and clay). I have not come across any references to people adding clay to ready-mix grout so far...

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  • Sixto
    replied
    My son helped me rake the concrete into place, since there wasn't an easy way to maneuver the wheelbarrow around all sides... I did the shuttling back and forth from the truck to the hole. Our friend Nick offered free advice, and my wife was the photographer from the roof deck...

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  • Sixto
    replied
    Originally posted by RandyJ View Post
    As for the construction are you planning a igloo style? I know a few have had issues in the cold and snow with water getting in and wrecking stuff. You may want to consider some kind of enclosure to help protect the oven from the weather. The biggest issue is that the weight will climb. Mine was i believe close to 16k#.
    Hi Randy, thanks for sharing your experiences! I ended up going down 2' below grade and pouring a 1-foot thick reinforced concrete footing. I laid down landscaping fabric on the undisturbed soil and added a couple of inches of sand/gravel above that to help with drainage immediately below the concrete.. The concrete pad is 5' side to side x 6' front-to back. I figured if there is any movement, the whole thing will more likely move up or down with soil moisture and frost conditions. It ended up being about a cubic yard of concrete, and rather than mixing it myself, I opted to have ready-mix delivered... it took about 15 trips of the wheelbarrow.

    So-far there is about 2100 pounds of block, mortar and grout above the foundation... by the time the brick dome/igloo style oven is finished, I'm sure it will be close to your figure which ends up being just under 4 pounds per square inch of net weight over the entire area of the foundation (assuming even distribution)... if my math is right, it's just a little over-designed... :-)

    I'm attaching a few photos of my progress... 3 photos per post... I will pause construction over winter and resume in the spring.

    Sixto

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    Last edited by Sixto; 10-21-2021, 10:40 AM.

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  • RandyJ
    replied
    Hey Sixto ,when i did my oven base i doug 12" around the outside of the base and 6" in the center. My soil was very sandy so had good drainage. I haven't seen the oven up close in over 2 years as we sold the house but i saw it from the street today as we biked past and it still looks to have not moved at all. I have been helping a friend build a garage and they did the exact same thing for the slab for that. So i would think you are ok to do something similar to that.

    As for the construction are you planning a igloo style? I know a few have had issues in the cold and snow with water getting in and wrecking stuff. You may want to consider some kind of enclosure to help protect the oven from the weather. The biggest issue is that the weight will climb. Mine was i believe close to 16k#. If you have questions send me a message and I would be happy to help .

    Randy Janssen

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  • MnDude45
    replied
    Take it easy, Sixto. That smoke last week was brutal. Keep plugging away!

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  • mongota
    replied
    Originally posted by Sixto View Post
    Just a quick update to say it's going slower than expected, with the heat and smoke in the air, plus my back making it difficult to dig more than one barrowfull per day. Hope to make more progress soon, once the foundation is poured. Thanks to all of you for responding so far, a friend posted out that October may be my deadline for mortaring bricks depending on temperature. I don't want to rush it and compromise my health or the quality of the build, but it would be nice to do the brickwork this year...More to come Sixto
    I started my oven late in the year, I think it was October. I'm in CT. But I HAD to get it started because it's one of those things I wanted to build, and I just kept slipping it back.

    I finally bit the bullet and I started to build the base in October. The idea was to get the base of the oven done from footings through the upper slab, then let it over-winter. In the spring I'd then do the brick dome. I remember doing my upper slab a couple of days before a forecast several day freeze. It was around 45 bag pour of 80lb bags of Quikrete. Didn't get started until late in the day, and it took a while for the water to burn off. I did the hard trowel late at night, around 11pm. Every time I'd swipe the trowel across the concrete, the "ring" of the trowel would be answered by coyote howls off in the distance.

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  • Sixto
    replied
    Just a quick update to say it's going slower than expected, with the heat and smoke in the air, plus my back making it difficult to dig more than one barrowfull per day. Hope to make more progress soon, once the foundation is poured. Thanks to all of you for responding so far, a friend posted out that October may be my deadline for mortaring bricks depending on temperature. I don't want to rush it and compromise my health or the quality of the build, but it would be nice to do the brickwork this year...More to come Sixto

    Leave a comment:


  • Baza
    replied
    Sixto - great progress! And you are getting really good advice here from some amazing people (all the folks chiming in have helped me immeasurably!).
    Mongo is right about the liquid barrier - just did my entire enclosure in same and it works really good.
    As for the draw - I'm just completing my curing fires and the 8" diameter, 4' chimney is drawing like a vacuum! I know there is an aesthetic you are after - but in this case - I think function over form wins the day - just wonder how your wife will feel about the charring of the outside of the oven mouth from all the smoke coming out the front? I would heed this advice mate.

    Dig deep - up here in Canada, and sitting in clay - I went down 36" until I hit bedrock and dug a similar base as Mongo. Framed and poured a massive amount of concrete in one pour (walls and final slab integrated). Wouldn't take chances here. Last slab I poured was a 40' x 25' one for a flagstone base and mortared the stones on top - even that one I went down 18" and was nervous.
    Sweat equity coming your way mate - well begun is half done and encouraging you to have a solid foundation for the fun that is to come!

    Best of luck with it all
    Barry

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  • UtahBeehiver
    replied
    While not quite as cold as MN here in Utah it can get sub zero here in the winter. I did a mono pour base about 6" with 8" welded wire mesh and #4 rebar around perimeter. The key for me was 8" of gravel underneath for drainage and to minimize frost heave. My soil is a sandy loam. I have not had any movement of the base. I would look at what you soil type is, if clay you will need to mitigate the soil expansion more than if it is a sandy loam. I think Randy J went both ways with his builds, you should PM him.

    PS, even though I am an engineer and had access to all types of CAD programs, I prefer the old pencil and graph paper and "slide rule" LOL, just kidding on the slide rule.

    Leave a comment:

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