Argentinian oven chimney Help

[Derocherconstruction]

I am building an oven that is close to the Argentinian oven found in a link from this forum. I am at the point of putting in the chimney. The questions that I have are about the size of the chimney, it looks like they end up with a piece of 4" cast iron pipe, like what was used for years as sewer pipe. Also the chimney is in back, I'm thinking the entry to the chimney is going to be just about an inch below the door arch opening, enough to let the smoke out of the oven, not the door. I know this is not the prefered method, but it looks like he has cooked some great pizzas and breads, etc, and this design fits into my little deck area, and will look like what I want. Thanks for any help or suggestions, Jim

[Jed]

Re: Argentinian oven chimney Help

Jim,

How big is your oven? I don't have confidence that a 4" 'chimney' will provide enough draw to vent your oven well..

Although I don't recall which oven was modified, I remember reading about one of our forum members who replaced a 6" chimney with an 8" chimney and there was a noticeable improvement in performance; I don't recall that his was a big oven, just a regular size...

Good luck with this project, it sounds interesting, and do post pictures!

JED

[dmun]

Re: Argentinian oven chimney Help

Hi, Jim.

Chimneys in the back are always a bad idea. The design of pizza ovens is to establish a circular airflow where the heat from the fire heats the dome, instead of being vented directly out to the outside.

Having an undersized chimney in the wrong place will waste a lot of time, effort, and firewood.

[Derocherconstruction]

Re: Argentinian oven chimney Help

As I look out the window with a wind chill of about 35 degrees, I am glad I wrote a few things in the forum this morning. I really like the look of the oven that I was patterning from, but it seems pretty obvious that the Argentinian oven is the only one with this little angled back of the oven chimney. He also covered the firebrick with red clay brick and then stucco, no insulation from what I'm getting out of the posted pics. I am at a point of putting the right kind of chimney in the front without much of any tearing out things, that's where I ended last night was quessing at the chimney height and angle and size. The oven is 32" inside, and I am progressing to a height of 17" inside at this point. I have the floor done, and I am on the 5th course of firebrick now. I think I understand what you mean by the flow of the incoming air now that I think about it, it comes in and feeds the fire, heads to the back and on up to the front to exit? I sure would appriciate anyones advice and ideas at this point, as far as chimney sizes and what to put on the firebrick next to keep plugging along on this project. I spent a lot of time looking at the Argentinian oven and it looks like he cooks lots of great stuff, but I have read hundreds of the postings here, and I can tell it's time to listen up, there are a lot of you guys and gals that have done this and seen the good and the bad. I am a carpenter, and don't have any knowledge of pizza ovens other than what I have read and seen in the last few weeks, so I'll yell one more time - HELP! Thank you for any help or advice on this project, I know everyones time is valuable, this forum looks like a lot of great folks who help just for the good feeling of helping someone do things the proper way, and end up where the hope to get, Thanks, Jim

[dmun]

Re: Argentinian oven chimney Help

I'm glad you came here before you built it. If you need a chimney at the back, you can angle it back above the dome, code allows for two thirty degree bends in a chimney run. There is a long tradition of back-venting south American ovens. Someone is selling some from Uruguay on eBay right now. That doesn't mean that it is a good idea. In the medium to long run, either your oven is easy and fun to use, and you use it a lot, or it's slow, and cold, and wood hungry, and firing it up gets put off to rare occasions.

Good luck with your project. We don't know everything, but at least a lot of us speak from personal experience.

[Dutchoven]

Re: Argentinian oven chimney Help

derocher
did you insulate under the floor of the oven?...now would be the time to decide what to di if you did not...then the next step is to make sure that your door is the proper height in relation to the top of the dome...should be about 60 to 63%...so between 10 and 11 inches should be fine...other than that I think you can continue to build...always try to think the next step ahead...how will you handle the vent and then the flue system...insulating the dome...etc...
We're here to help!
Dutch

[Derocherconstruction]

Re: Argentinian oven chimney Help

The base is filled with broken concrete, then beach sand [ 3 - 4 in. ], then 4 in. of fire clay/portland cement mix, then the fire bricks on the flat. No perlite or other insulation like that. I will measure the door opening size that I formed up yesterday, I can change that easily, but the oven floor is set in stone pretty much... Any thoughts on the door opening size and chimney size? Thanks, Jim

[gjbingham]

Re: Argentinian oven chimney Help

I'd recommend breaking it apart and putting insulation under the floor. 4 inches minimum. I think you'll be very unhappy with the performance of your oven if you skip this vital step. A hot floor is paramount to cooking multiple pizzas or baking bread. Without the insulation, your heat will drain out to your slab and foundation as fast as you apply it with fire in the oven.

[Frances]

Re: Argentinian oven chimney Help

I'll chime in on this, too. If there is any possible way to put insulation under the floor, do it. Are the bricks of the floor cemented on to the fireclay postland mix? Otherwise it might be an idea to remove the bricks, add an insulation board and replace the floor... it'd make the floor higher, but maybe you could make the dome higher, too, and it would really really be worth the trouble!

[dmun]

Re: Argentinian oven chimney Help

You can lever up that floor, shop-vac out that worthless sand, and replace it with vermiculite concrete. Trust me, NOTHING will pay more than proper insulation. DO IT NOW while you have the chance.

Remember the Forno Bravo Forum mantra: Insulate! Insulate! Insulate!

[Dutchoven]

Re: Argentinian oven chimney Help

derocher
I will agree also...question is did you attach the floor or did you just lay them in dry or with fireclay...you will not be happy without insualting that floor...your oven will never really get to and hold any good pizza temps and anything close will be lost quickly...that floor would be a huge heat sink...something brought you to this site now and I think it was this potential flaw...really necessary to figure out how to insulate that floor and then we can make sure of door opening size etc.
Best
Dutch

[Derocherconstruction]

Re: Argentinian oven chimney Help

Is there a way to put the insulating board on top of the floor bricks that I have there now, then more firebrick cut to size over the top of the insulating board maybe? I have the firebrick mortared to the fireclay/portland mix. There is no way to get below there without tearing everything down and starting over. I am trying to figure a way to get some insulation in the existing oven, and maybe use 1 1/4" firebrick over that, and salvage what I've done so far. If i could get the existing firebrick off of the floor, then pour insulating cement, then the thinner fire bricks I'd have 2 1/2" of insulation, and only lose 1 1/4", or re-use the existing firebrick that I'd remove, only losing 2 1/2", I could make up for that yet, I,m on row # 6 right now. Thanks for the help and advice, Jim

[Dutchoven]

Re: Argentinian oven chimney Help

That could work...I would suggest using the Forno Bravo insulating board rather than the vermicrete...you would need the best insualtor possible...they are 2 inches in thickness and they could be cut to fit the floor and then floor bricks...
Best
Dutch

[Derocherconstruction]

Re: Argentinian oven chimney Help

I was able to pry off the existing firebrick, leaving only a few to support the dome. I will insulate either with the fb board of something that I can find locally. I would prefer to find a local insulation and get that done, and replace the floor over the new insulation. I can change my dome template to get back on track once the floor is insulated, and firebrick cut in place. How would 4" of perlite/portland mix compare with the fb board? Any other possibilities using materials from the big box stores [ home depot, menards ]? I will be putting the chimney in the front and giving up on the Argentinian chimney scheme, I have a 6" masonary flue that I will use. Thanks, Jim

[dmun]

Re: Argentinian oven chimney Help

Congratulations on your decision to insulate. You won't regret it.

Four inches of vermiculite concrete will work pretty much as well as two inches of FB board (Calcium silicate)