#11  
Old 05-29-2009, 01:56 PM
Serf
 
Join Date: May 2009
Location: Lancashire UK
Posts: 3
Default Re: Newbie with an issue

Okaydokay guys thanks for all the help on this, Ive got a few piccys.

Fires, Ive had about 5 now, started small then bigger.

Had another session tonight but still not much luck with it, one of the piccys which shows the fire, clearly shows the level of heat from the smoke layer, anything under the smoke is relatively cool, in the smoke hot as hell.

Other piccys show the top, which is refractory concrete, this Im going to add a good layer of vermiculite mix.
Other piccy shows the front which is direct into the oven, I dont really have much solution to getting insulation on the front so will have to live with that one, the back is the same but I can get some insulation on that so will do a mix of vermiculite as on the top.

Im wondering if it would be worth while cutting a slot in the top to act like a chimney, Im pretty sure its starved of oxygen as when I shove the fire to the back it kills it or almost does, the piccy shows flames but Ive had to keep blowing it to keep it lit.

Sides are a double layer of firebricks with about ab inch of concrete between them, they havent yet got warm....


Below the concrete is a little tricky but Im either going to cut a hole in the base and bodge some insulation in or go for heat resistant expanding foam (easier to install). Anybody used expanding foam??

To me it just seems like its not hot enough, reading a few threads and other places people say its hot enough when the carbon burns of the bricks, hasnt happened yet.
Does different wood burn at diff temps?

Thanks again
Ben
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Newbie with an issue-flames.jpg   Newbie with an issue-side.jpg   Newbie with an issue-top.jpg  
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  #12  
Old 05-30-2009, 05:33 AM
mfiore's Avatar
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Join Date: Oct 2007
Location: Michigan
Posts: 919
Default Re: Newbie with an issue

Ben, do you have temperature measurements? How big are the fires? The fires that burn off the carbon are big (scary big). Yes, different woods burn at different temps. Somewhere in these threads someone published a chart with different woods and burn temps. With big huge, hot, long fires, you may be able to get to high temps, but if not insulated, you won't be able to retain.

Good luck
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  #13  
Old 05-30-2009, 07:36 PM
Apprentice
 
Join Date: Feb 2009
Location: Australia
Posts: 118
Arrow Re: Newbie with an issue

Ben,
just looking at your thread and now your pictures, you have a variety of problems which are not 'easy fixes'!
As mentioned, you are :
1. seriously lacking in insulation:
- especially under your hearth bricks,
- at the back of your oven,
- on the sides and top, and
- on the front of the oven.
2. your fires are not hot enough to achieve the better temperatures to get those pizzas cooking crisping in a short time,
3. your oven entrance/arch is a little low (which is beneficial in preventing heat from flowing out of your oven) but may be too low if you plan on insulating under your floor, which is in my opinion a 'must do'!
When you cook your pizzas, try as I do, push your fire to one side rather than to the back and get more wood and flames into it. The flames should be high enough to run up your walls to the centre of your barrel. You don't have enough heat to start with, and are loosing too much through your floor sides, top and back.
If it were mine, I would:
1. remove the hearth bricks and put a double layer of insulation board (yes it will be more expensive than vermiculite cement, but you will save considerable height inside your oven). Then re-install your hearth brics.
2. Remove the second layer of firebricks from your walls From what I understand is that you have a full 9" plus cement bonding them as a heat sink which is way way too much. A single half brick )4 1/2") is more than ample. Put an insulation blanket over your single barrel bricks or 3 to 4" of vermiculite cement insulation.
3. Carefully cut out the mortar in your oven arch bricks and using a diamond blade, carefully replicate the arch around 4" higher than it is at present (to allow for the 2" of insulation board and an extra 2" for easier access for you if you require it. This should be quite easy to do as your front face bricks are more like larger blocks and will easily hold in place during the 'renovation'.
Re install your arch bricks using your original form work and pack the top mortar joint with mortar to ensure that it is good and completely through.
From your pictures, I can't see how you can insulate behind them without removing them and bringing then 4" forward into your oven and losing valuable cooking space.
I think then that with better fires, you will enjoy your oven as it will get hotter with less wood, hold the heat longer, and be more enjoyable.
Sorry mate, but I don't see any easier way to fix the problems.

Cheers.

Rastys
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  #14  
Old 05-31-2009, 12:10 AM
brickie in oz's Avatar
Il Pizzaiolo
 
Join Date: Mar 2009
Location: Whittlesea
Posts: 3,455
Default Re: Newbie with an issue

Quote:
Originally Posted by BenBaron View Post
Does different wood burn at diff temp?
There is the same energy per kilogram of wood in most species, so wood type isnt the factor.

Your design is all wrong and no matter how much you dick around with it, it just wont change or work.

The first pic you put up showed slow lazy smoke, now Ive built many a fire place and chimney and know all about how they should work correctly to achieve a decent draw and hence a decent fire.

A properly designed and built wood fire pizza oven is nothing more than a chimney that is laying down, or more correctly, a well designed chimney is nothing more than a good designed and built wood fire pizza oven that is standing up seeing as how the ovens were here first.....

You have to have a restriction in the fire box to make the thing draw properly, its called a ventura.
Without the ventura the fire wont burn.
The ventura restricts the flow of air/oil/vapour/fuel(what ever), etc, with any restriction there is an increased flow/velocity.

Its the restriction that causes the fuel to burn correctly.

Ill post some diagrams of how it all works later.

Uploaded, the pics are a cross section of a fire/pizza oven.

Without these basic elements in your oven/fireplace, the fire just wont burn.
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Newbie with an issue-fireplace.jpg   Newbie with an issue-pizza-oven.jpg   Newbie with an issue-pizza-oven2.jpg  
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Last edited by brickie in oz; 05-31-2009 at 12:54 AM.
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