New guy from NJ

[DJVoorhees]

Re: New guy from NJ

Heat transfer depends on the delta T btw the interior oven surface and the outside of the bricks in your case. That is 650 - 110 = 540. The bigger that number is the more you are trying to heat up the universe. Insulation will help, but then you have the two big holes (door and flue) that are dumping your heat out of the oven. The second law of thermodynamics says the the universe moves to disorder (randomness). An oven is a very ordered system and is all the time trying to move in the direction of disorder, unless you do something to prevent that, like insulation. If you throw a bucket of tennis balls into a room they will come to rest in a random manner, they will not all rush to one corner of the room. It just doesn't happen. That is what you are asking the heat to do, stay in the oven. It's not going to happen.

This forum has a vast knowledge of WFOs and expertise in making well designed WFOs. If you don't want to take their advice, you should go elsewhere.

People are having a nice conversation here. Im not sure where the comment "If you don't want to take their advice, you should go elsewhere" came from. Did it make you feel good to say?

[lwood]

Re: New guy from NJ

Heat transfer depends on the delta T btw the interior oven surface and the outside of the bricks in your case. That is 650 - 110 = 540. The bigger that number is the more you are trying to heat up the universe. Insulation will help, but then you have the two big holes (door and flue) that are dumping your heat out of the oven. The second law of thermodynamics says the the universe moves to disorder (randomness). An oven is a very ordered system and is all the time trying to move in the direction of disorder, unless you do something to prevent that, like insulation. If you throw a bucket of tennis balls into a room they will come to rest in a random manner, they will not all rush to one corner of the room. It just doesn't happen. That is what you are asking the heat to do, stay in the oven. It's not going to happen.

This forum has a vast knowledge of WFOs and expertise in making well designed WFOs. If you don't want to take their advice, you should go elsewhere.

[lwood]

Re: New guy from NJ

Try getting your ovens up to 900F. Bet it will be very difficult. Dome ovens are not that difficult to build, particularly with the "indispensable tool" (IT). Sorry to say, that design wasn't given much thought. It may cook a pizza but that's about it. Of course, if you have never cooked with a properly designed oven, you wouldn't know the difference.

With a properly insulated oven, the exterior should not be warm to the touch.

[DavidApp]

Re: New guy from NJ

I found that having the fire to the side rather than at the back of the oven made it easier to get the pizza cooked more evenly.

I used dough from the book Artisen Bread in 5 minutes a day.

Good luck with your Pizzas.

David

[DJVoorhees]

Re: New guy from NJ

Looks great - I bet it was delicious!

I fired mine a bit more aggressively last night and some small cracks appeared. I'm not sure there is any way to prevent it with such a tick, heavy structure.

I'm going to make pizza this weekend, I'll report back with my success or failure, lol..

[DavidApp]

Re: New guy from NJ

Hello

The Pizza was good. I made the first one a bit too thick but the rest were good. It will take a few attempts to get everything to work well.

I have included a photo oh the bread.

I think I will close up the entry a bit to get to the 63% of dome hight and set the pillars back from the front arch so there is a step for the door to seal against.

David

[DJVoorhees]

Re: New guy from NJ

Hello.

I think I did about 6 or 7 curing fires following the info from the other site. The first few did not heat up the outside bricks. I noticed a small crack developing on the 5 fire. The crack got larger as I got the oven hotter but closed as it cooled.
The first fire I had to cook pizza I did get the carbon to burn off and my IR thermometer showed 650+ on the back wall and dome.

I have made a door that I can push in as far as the chimney to try to hold the heat for bread but I have not done a damper yet.

Thinking about the design it is hard to see how it can heat up without something cracking. I did mortar the arch to the hearth which may have been a bad move.

Building this oven has given me the confidence in my brick work to try a dome type oven.

David

Thanks for the info.

Sounds like the crack really doesn't effect the oven operation. These ovens are really meant for occasional use for pizza and other quick stuff. While I do think bread is a possibility, its likely not the best set up.

I'm going to use small fires for a couple hours to heat the oven up prior to getting it to full temp. I am also using the chimney openeing as a dampner, simplu using 12x12 paver stone over the top to decrease/increase the opening manually.

I fired mine yesterday for the first time with a small fire and it did hold some heat, so far so good.

How was your pizza?

[DavidApp]

Re: New guy from NJ

Hello.

I think I did about 6 or 7 curing fires following the info from the other site. The first few did not heat up the outside bricks. I noticed a small crack developing on the 5 fire. The crack got larger as I got the oven hotter but closed as it cooled.
The first fire I had to cook pizza I did get the carbon to burn off and my IR thermometer showed 650+ on the back wall and dome.

I have made a door that I can push in as far as the chimney to try to hold the heat for bread but I have not done a damper yet.

Thinking about the design it is hard to see how it can heat up without something cracking. I did mortar the arch to the hearth which may have been a bad move.

Building this oven has given me the confidence in my brick work to try a dome type oven.

David

[Tscarborough]

Re: New guy from NJ

I will be a wet blanket. That oven design is horrible. I called them and they are clueless about thermal dynamics. The outside of the brick will always be cooler than the inside when in use, thus the oven will constantly lose heat to the exterior. It may stay warm for hours, but not hot. Sorry, but they mislead you (and a lot of other people).


That said, you can still use the oven, it is just (very much) less efficient than one built to the proper design.

[DJVoorhees]

Re: New guy from NJ

Thanks for the info!

Wow, an oven that keeps its heat for days is really impressive. I definitely understand the issue, for sure. I don't plan on doing anything but cooking some pizzas for dinner and party's. I will likely only use it a couple times a month. so Im hoping it makes a good starter oven.

I'm sure it will inspire me to build a larger, better oven.

[mrchipster]

Re: New guy from NJ

Yes, I starting to understand that. Thanks for the info.

Just curious - when you say the floor temp is 20-50 degrees over ambient, do you mean the ambient outside temp?

I would think that the fire burning on the floow would impart lots of heat given you heat it well.

The 20 - 50 degrees over ambient is outside the oven -- layers are listed top to bottom.
(All temps measured with an IR thermometer.)

Layers

Inside oven at ceiling firebrick 4.25 inches thick - 950F
Firebrick floor of oven 2.5 inches thick - 800 - 900F
Ceramic Board insulation 2 inches - Unknown temp
Vermicrete insulation 2.5 inches - Unknown temp
Concrete structural layer 4.5 inches thick
Outside bottom surface of structural layer 20 - 50F above outside Air temp (ambient). after about 5 hours at 800 - 900F inside the oven

From - the web site you linked to it states ---

"How hot do the ovens get and how long can they hold their heat?
The ovens can get up to 900+ degrees and can hold their cooking heat for hours! You can cook for
hours off a single firing! For a longer cooking experience, you will need to occasionally add a piece of
firewood to increase the heat."

A well insulated oven should keep heat for days not hours, and always needing to add wood is a costly solution; And might not be what you want for certain types of cooking.

I can cook for up to 6 days after raking out my coals. I need to wait until two days after a Pizza party to cook bread at 550F. because the oven is still to hot. Today there are ribs going in the oven at 240F from a fire I had on Friday. and I baked 60 rolls of bread on Sunday. Again there has been no "Fire" in the oven since Friday - just cooking on retained heat.

I am not trying to be a wet blanket here but trying to get people who are not insulating to understand the issue.

I am sure you will have great fun with your oven, Please enjoy it and have lots of pizza parties.

Chip

[DJVoorhees]

Re: New guy from NJ

I hope you have a large, low cost source of wood. Without insulation under the oven you will lose a bunch of heat into your structure. With 4.5 inches of insulation under my floor bricks I still read 20 - 50F degrees over ambient radiating into the ceiling of my wood box below my oven, after long burns.

Putting insulation over the oven will help but heat being sucked out the flue and into the floor will still be a major issue.

And a lack of a way to damper the flue, or completely isolate it from the firebox you will loose a great deal of heat after the fire goes out. Not much chance for bread baking here.

Best of luck.

Chip

Yes, I starting to understand that. Thanks for the info.

Just curious - when you say the floor temp is 20-50 degrees over ambient, do you mean the ambient outside temp?

I would think that the fire burning on the floow would impart lots of heat given you heat it well.

[mrchipster]

Re: New guy from NJ

The idea behind these ovens is the thickness and the amount of firebrick used in the construction. The oven is 5-6 inches thick and all firebrick. IT supposedly holds heat that way - no insulation and no door needed. I am however thinking about the insulation just like DavidApp said.

I am also going to build an archway in the front of my oven and close it up a bit, and make a door.


Similar to this one.

Build A Wood Fired Brick Oven / DIY Pizza Oven by BrickWood Ovens

I hope you have a large, low cost source of wood. Without insulation under the oven you will lose a bunch of heat into your structure. With 4.5 inches of insulation under my floor bricks I still read 20 - 50F degrees over ambient radiating into the ceiling of my wood box below my oven, after long burns.

Putting insulation over the oven will help but heat being sucked out the flue and into the floor will still be a major issue.

And a lack of a way to damper the flue, or completely isolate it from the firebox you will loose a great deal of heat after the fire goes out. Not much chance for bread baking here.

Best of luck.

Chip

[DJVoorhees]

Re: New guy from NJ

Good point.. Where does the door seal?? and where is the flue in relationship to the door?

Chip

The idea behind these ovens is the thickness and the amount of firebrick used in the construction. The oven is 5-6 inches thick and all firebrick. IT supposedly holds heat that way - no insulation and no door needed. I am however thinking about the insulation just like DavidApp said.

I am also going to build an archway in the front of my oven and close it up a bit, and make a door.


Similar to this one.

Build A Wood Fired Brick Oven / DIY Pizza Oven by BrickWood Ovens

[DJVoorhees]

Re: New guy from NJ

Hello from Georgia.

I have just finished the same type of oven. I did not buy the form from them just made my own form.

You need to take it very slowly as you fire it up. I thought I was going slow enough but ended up with a small crack from front to back and one in the back wall. The crack opens up as the oven heats and closes up as the oven cools.

I plan to build a housing over my oven and fill it with vermiculite insulation because the outside of the oven got very hot and the oven did not hold the heat as long as I expected.

David

Ugh, that stinks. How many curing fires did you run through before trying to bring it up to temp? Im getting ready to start my first small curing fire today. Im just going to burn a few small pieces of wood very "gently".

Looks like we built the same kind of oven.