Using Quikrete instead of Portland?

[Ken524]

Re: Using Quikrete instead of Portland?

Sounds really interesting (and fun!). Keep the pics coming.

[adman2u]

Re: Using Quikrete instead of Portland?

Ken see my photo - trying to post first picture - You can see how firebox and flue go together adman2u - it also gives you and idea of how thick my concrete is going to be - the whole thing is sold - jeeze I might need two cords of wood to cook a doughnut!

[adman2u]

Re: Using Quikrete instead of Portland?

Ken H
If you look at the pictures posted you can see my flue is a regular large chimney flue. The oven or firebox curves fast on the right side and not so much from the left facing the opening. I did this to give myself a place to radiate heat back down. The back also curves dramatically but front none. Keep in mind I am making this up as I go with little or no experience. BUT I'm a good researcher. Anyway I build a fire on the right under the curved part of the ceiling to load heat and walls then will shift it right under giant 13X 17 flue when cooking. This is a straight shot up from the firebox. The first flue is cut at 12 inches so it is 12 inches high. Then you see I cut in firebrick ledges on corners to hold my grill or firebricks. The flue I can block off to any size I want with firebricks. I hope this will act to reflect heat and reduce air. I added another 6 inches of flue above that. You can see the pictures I posted. So far I can only detect human error by the chef! I need a smaller fire for smoking. When it cools off I will try baking - bought yeast last week - Will post more pictures when the tile and stucco is dome. Remeber this unit is two sides or front and top!

[adman2u]

Re: Using Quikrete instead of Portland?

Breven
I have cooked in it already - my experience comes from building a big fireplace on my patio and a smoker (from mud & bricks - honest) I had researched for 2 years before building fireplace. Cracking and expansion is the biggest issue there. It is 3 years old and no cracks. Anyway I love to smoke stuff and a hurricane wiped out my smoker using my carport roof. I started thinking smoker then oven then tandori grill. This unit is super efficient in heat transfer so I'm burning stuff. The tandori part is fantastic. I can cook a whole chicken in 30 minutes to perfection. I smoked one thing and burned it in 2 hours. My old smoker took a bunch of wood and lost tons of heat. I need to learn. and I intend to build a "smoke house" for my top. Something good looking to set over flue. But the oven thing is all new. I have baked potatoes! Its too hot in FL to mess with it now. I am worried about your assesment of my wood usage. It has been my concern all along but I will tell you by closing the door and the chimney with fire bricks it really closes down the fire. I really hope your wrong about my floor. I see Ken H has said he thinks my floor it too thick? How crazy is that - we are all just having fun

[Ken524]

Re: Using Quikrete instead of Portland?

adman2u:

I've looked at the pics and I'm a little puzzled. I don't have the big picture on the project yet. Can you post a couple of pictures of the whole project?

Does the chimney exit the very top of the oven dome or will it be catching the exhaust exiting the front door of the dome? Is the floor of the dome where you plan to bake pizza?

I'm concerned that the floor may not get hot enough for pizza due to all the thermal mass below it.

[Breven]

Re: Using Quikrete instead of Portland?

Now that I look at your pics, I see you have a very intersting design. I'm not really the right person to ask, I'm working on my first oven too. I'm in the curing process now, so I don;t even know how long it's going to take to heat up my oven. I built the Pompeii style oven and followed the examples. On my own, I would have no idea what to do.

You should probably follow the curing process steps though before you build a big fire in that thing.

[adman2u]

Re: Using Quikrete instead of Portland?

sorry I'm new here I sent reply but its posted below - would like your comment

[adman2u]

Re: Using Quikrete instead of Portland?

Interesting but I'm done so modification is not happening. I have six inches of solid concrete on the ground not suspended like many ovens. Then a layer of firebrick thats about 3 inches. I have at least 9 inches of masonry on bottom - our soil is pretty much sand.
The top is firebrick and parged with insullation about 6-8 inches total a layer of cardboard for expansion and then poured solid up to 18 inches.
What do you think I can expect in charging and how long do you think my heat will stay hot? I never had an oven before. You can see some pictures in photo gallery look adman2u. I have not baked any bread or pizza yet.

[Breven]

Re: Using Quikrete instead of Portland?

JR-

Download the instructions on how to build an oven from this site. Follow them. Though there are many adjustments that can be made to suit your needs, the basics are covered. I literally printed the instructions, along with pictures of oven progress from people on the site and just did what they did.
The mixing of Concrete rather than cement & vermiculite might be the first of many problems you can avoid. For us novices- best to follow the lead of the experts.

[james]

Re: Using Quikrete instead of Portland?

You don't need to take anything out -- you can always add an insulating layer above what you have; either 4" of vermiculite concrete or 2" FB Board. Either way, I think it is worth the little bit of extra work and cost to make sure your oven really performs well. You'll be happy you did it when you are cooking.
James

[dmun]

Re: Using Quikrete instead of Portland?

While I am new to this site I am not new to the heat and insullation concept. Heat rises! I think that a firebrick bottom with any form of concrete base should work if the top is thick enough.

This has been tried and tried again with the same results. If you are baking bread you might, just, get away with a firebrick on masonry or rubble/sand/glass/gravel layer, if you have unlimited time and wood.

But for pizza, we really need that floor to be hot, and to stay hot. It can only be recharged by the radiant heat, so we need thermal isolation under that floor, or the heat will be sucked away.

Insulation isn't free, but neither is fuel, even if you cut it yourself. There really isn't any reason not to insulate under the floor.

[adman2u]

Re: Using Quikrete instead of Portland?

While I am new to this site I am not new to the heat and insullation concept. Heat rises! I think that a firebrick bottom with any form of concrete base should work if the top is thick enough. The purpose of curved oven tops and in a fire place angled sides is to radiate heat. My own oven / smoker / grill has seven inches of foundation then firebrick on the bottom. I used full firebricks for the box with 4 or 5 inches of cement / vermiculite a layer of cardboard for expansion then solid concrete. My weakest link is I have an actual flue thats 13 X 17 for heat to escape. I have a way to neck that down or close it with firebrick. In about a month I will be able to try the oven. It is new and I don't want to crack anmything. Plus it is to hot outside (FL) Pictures posted yesterday

[asudavew]

Re: Using Quikrete instead of Portland?

I used 72 cups (18 4 cup scoops) to one 90lb bag.

I know you will hate to hear this.. but I think you need to redo it. Or form another insulating layer on top. I think what you have now will simply wick your heat out. And your firing times will be long, and your wood consumption will be high. It will cost you in the end.


The insulating layer should be 5 parts verm to 1 part Portland cement and just enough water to hold it all together. Mix the dry ingredients first, then slowly add water until you can just squeeze a little water out the mixture with a closed fist.


I have a 3.5 - 4 inch layer of the vermcrete under my oven, and I wish I would have built it up to 6 inches or more.

Just my opinion, but I'd hate to see you build an oven that is hard to use, under cooks the bottoms of your pizzas, and burns the tops.


Let us know what you do.

Dave

[adman2u]

Re: Using Quikrete instead of Portland?

At my home depot they sell ALL of the broken bags of concrete products for $4.10 - I do mean all - if they have six broken bags its just $4.10 TOTAL I used stucco on the outside of my last cooker and got two bags plus seven quick crete for $4.10 That stuff is $17 per here in FL. - what a bonus if you have a way to transport.

[JRDeMeo]

Re: Using Quikrete instead of Portland?

I used 72 cups (18 4 cup scoops) to one 90lb bag.