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-   -   Door design questions (http://www.fornobravo.com/forum/f9/door-design-questions-924.html)

maver 08-25-2006 12:42 PM

Door design questions
 
I built my dome with an arched entry and side flares - there is enough narrowing to snugly fit a door against for retained heat cooking, but the shape is not as simple as it could have been (in retrospect). At any rate, I have several thoughts on how to craft the door but would like to solicit the forum for feedback. I could craft a door out of hardwood and cut it to fit. I would most easily be able to do this with oak. If I use this design I could wrap the oven surface with flashing to protect it from the heat or just wait until the temperature drops enough (what is the proper temp to wait for though). I was also considering casting a door from perlcrete wrapped with metal flashing to protect it from falling apart. If I do this I would reinforce with metal and leave metal protuding to apply a wood backer and handle to it. I know a fabricated metal door would work well but I am trying to keep costs low and manage all of the craftsmanship myself.

As a second matter, in curing or in deciding when to apply the door to the opening there are specified temperatures to do these things. I have an infrared thermometer and see very different readings while burning wood at the top of the dome, at various heights of the dome and on the oven floor. I've used an area about 2/3 way up the dome as my reference point for measuring temperature during curing (hit 730 degree F this am, tomorrow I'll make my first test pizzas!). The oven floor is often 200 degrees cooler than the dome. When pizza is cooking is the floor expected to be 800 degrees, or the inside of the dome?

james 08-25-2006 12:58 PM

How many fires have you had? My guess is that you are still driving moisture out of the oven, so that the spot where the fire directly hits is reach 700F, but the thermal mass behind it is as hot, and the floor isn't heating up as fast as it will when the oven is fully cured. I'm guessing the entire dome -- all the way down the sides, isn't going white yet.

Don't rush it and your oven will keep getting better every time you use it for the next couple of weeks.

You could do a lot of roasting and grilling while the oven is still curing.

James

maver 08-25-2006 02:28 PM

curing is about done
 
I've been curing for the past 7 days. 700F is the opposite side of the dome from the fire about 2/3 of the way up. I have not tried to measure directly over the fire (which I am burning to one side of the oven). With the fire this morning at 700F I was starting to burn off the soot over the fire but not for the whole dome - I spread the coals when I hit 700F to stop it from getting hotter. I can tell a big difference in the past few days with how fast it heats up - I reached 700F in about 1/2 hour or less, starting with a small kindling fire right under the chimney. The inside top of the dome is more than 700F. Perhaps the 200 degree differential between middle of the dome and floor has to do with keeping the fire on for only a short time in the curing stage - maybe that will change as I start to cook with it.

Do others with infrared thermometers or thermocouples see equal temp floors and upper dome? I imagine there is going to be a heat gradient when the fire is burning, much less if the fire is removed and a door covers the opening. I was just wondering if my decision to use a spot about 2/3 way up the dome makes sense to determine when curing temperature each day is done. I know with pizza this will be irrelevant - I'll heat it to the temp that best cooks the pizza :D

I'm still more interested in the first question about door design and whether anyone with wood doors places it over the opening right after removing the fire or whether they wait to let is cool a little first. Anyone with metal flashing covering the door have problems with the metal degrading (either from heat or from rubbing on the bricks)? I'll probably just proceed with the percrete core door.

maver 08-27-2006 09:59 PM

perlcrete filled door
 
To answer my own question, I cobbled together a door shortly before our second firing of the oven. I ended up sandwiching perlcrete between concrete board (inner layer) and a cheap piece of plywood (outer layer), wrapped the inner side with heavy duty aluminum flashing which I screwed back onto the plywood. If I had a better seal from the flashing wrap I would have used loose perlite. I added the cement (and threw in a little lime rather than opening a fresh bag of portland), bound it together, gave it a full hour of curing prior to throwing it into duty. This is still more a test of concept, I have a neigbor who has offered to have his machine shop craft me a custom door of heavy grade stainless steel (in exchange for pizza :o ). Does anyone have an opinion on the real value of having insulation in the door vs just having a basic cover for the opening made out of heavy steel?

CanuckJim 08-28-2006 03:38 AM

Door
 
Maver,

Depends on what materials you're using, I guess. You should insulate the bake door if there's anything even remotely combustible in the make-up, and, of course, to retain heat. Traditionally, bake ovens in Quebec have heavy cast iron doors hung on pintels. Stainless should work just fine, but you will get radiant heat loss through the metal, and it will get HOT.

Jim

fdn1 09-25-2006 01:45 PM

Oven door material
 
Maver

This response would seem to be a little late to provide useful informatio to your question since it seems that you have already decided which material to use for the oven door.

It might, however, prove huselful too others who may have the same question and have not made a decision..

Our oven door was made out of a solid piece of 4" thick Beechwood that had been aged for about a year. We insert the door after removing the coals and the door has experienced no ill effects over a year of (infrequent) use. The dome temperature is in the 900 degrees to 1000 degrees range prior to removing the coals.

maver 09-25-2006 08:36 PM

Thanks Fred, I crafted a door for my father's oven (he is Guido di Napoli, by the way) out of 2 1/2" red oak, although I covered the inside face of the door with metal flashing. The solid wood door is a great look but his is usually just replaced once the oven has cooled - glad to hear that unprotected wood has not become badly charred. I think my very first post has a picture of his door. It's massive, his oven opening is pretty wide. I'd love to see a few pictures of your door, if you don't mind, including pictures of the inner surface. I rebuilt my original prototype with a better cured perlcrete insulator, tighter flashing, a think plywood outer facing and a proper handle. It works well, although I beat it up at bit and sometimes place it over the opening while the coals are still gassing in the oven a bit.

Fio 09-25-2006 09:25 PM

Consider Fiberfrax Board
 
My new draft door (pix coming) is a piece of plywood with two upside-down shelf brackets for feet. The shelf brackets face outside the oven. The inside surface is thick aluminum; sandwiched in between the aluminum and the wood is 1" of Fiberfrax insulation board. Drywall screws through the aluminum go through the fiberfrax board and anchor in the plywood. Heat is reflected from the aluminum; that which is not reflected is repelled by the fiberfrax board. It's lightweight and very effective.

Though it's a draft door, you can use the same design for a regular door.

maver 09-26-2006 08:37 AM

Oak Door
 
1 Attachment(s)
This is follow up for Fred, a picture of the door I built for my dad's oven. Oak.

fullback66 10-31-2007 07:09 AM

Re: Door design questions
 
Can you laminate oak boards together to make a thicker door. Is it not good to have glue in the wood? Would the heat cause some type of reaction.

question on doors.
When coals are ready and you are cooking. Do you put the door in opening while food is being cooked?
or-
Do you leave door off while you are cooking and only put door in when storing it for next time?

I would like to see more pictures of doors.
thanks,
fb66


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