Oven Door? Insulated or not. Pros & Cons

[kebwi]

Re: Oven Door? Insulated or not. Pros & Cons

Mine doesn't usually drop to 250 for 2+ days after a full regimen of pizza and bread using an AAC or perlcrete door (both of which have failed).

Are you referring to a scenario in which you intentionally let the oven cool down after pizza to bread temperatures, cooked bread, then doored it up for two days...such that the tempt did not fall below 250 for 48 hours?

...or are you dooring it up at pizza temps immediately...which would clearly hold heat longer than the bread scenario?

In short, I'm not sure I like my door thermometer very much. It always ready surprisingly low. I bought a standing 600F thermometer that I'm going to put inside the oven next time, just to see how it compares to the door thermometer.

Sigh.

[david s]

Re: Oven Door? Insulated or not. Pros & Cons

Most of the time after cooking we are so full that we lack the enthusiasm to cook something else. However, it always seems like a waste to let that heat out so we're tempted to put the door on even though the oven is empty. We usually try to cook a loaf of bread, but have to wait for ages for the temp to drop to bread baking temp.

[Tscarborough]

Re: Oven Door? Insulated or not. Pros & Cons

"The next morning, probably 13 hours later, I was at 250 with the door on."

Mine doesn't usually drop to 250 for 2+ days after a full regimen of pizza and bread using an AAC or perlcrete door (both of which have failed). I cast a new one from fibered insulating refractory repair mortar Saturday. It is heavy, but it is also insulating and strong.

I certainly think that having no door or an uninsulated door will lose a lot of heat. If you are not using the post-pizza heat for other things, I guess it doesn't matter though.

[mrgweeto]

Re: Oven Door? Insulated or not. Pros & Cons

I just built a door out of aluminum. The company infront of out building was replacing their sign with a larger one. It was heavy gauge aluminum so I stripped the paint off traced the pattern of the opening on it and cut 2 pieces from it. I then sandwiched 1/2" Durock inbetween the 2 pieces. I sprayed Black high heat engine paint only on the outside and attached 2 wood handles made from leftover railing material I had saved. Alle this was attached with stainless screws nuts and bolts. I then had some copper automotive paint that I brushed on the front to give it an antiqued look. Tried it lastnight after the oven cooked up about 16 large pies. At the point in time I put the door on the temp was approx 450 degs and I had no problem touching the front of the door metal surface with my hand and certainly the wooden handles were just fine. I will post some pictures later today or tomorrow under finished ovens in the photo section.
Guy

[GianniFocaccia]

Re: Oven Door? Insulated or not. Pros & Cons

The idea of an expanded metal door with exposed hi-temp insulation is kinda scary, yes?

[david s]

Re: Oven Door? Insulated or not. Pros & Cons

Stan,
I think you are correct, the door is the weak link. But if the oven meets your needs, so what. Also the smaller the oven, the larger the door opening, relative to the the ovens size, which exacerbates the heat loss through the door. A small oven will have a fairly wide door while a huge oven door looks more square.

[Stan]

Re: Oven Door? Insulated or not. Pros & Cons

dmun,

I'm not sure that it's only a matter of mass, but I admit that mass matters.

I had a large party last week with the oven at pizza temp (900+) for well over 3 hours. The outside of the oven was warm to the touch for around an hour while the inside was screaming along. The next morning, probably 13 hours later, I was at 250 with the door on. There's no way the masonry wasn't completely saturated with heat, and to my eyes the Primavera's walls and floor are just as thick as the FB Casa.

I would think that fully saturating any amount of masonry, regardless of oven size, would result in that heat being radiated back at a consistent rate. If I'm not losing heat through the insulation layer, and my IR says I'm probably not, what else is left but the door? My insulation will be the ambient outdoor temp while my door is over 500 degrees. That heat's gotta go somewhere. To me, the door seems like the weak point in the system.

Or, I'm completely out to lunch...
Stan

[lwalper]

Re: Oven Door? Insulated or not. Pros & Cons

I've seen a couple of doors fabricated from expanded steel (or aluminum?) formed into a bit of a cage sort of thing to fit the opening, stuffed with hi-temp insulation. Seems like that combo would weigh very little (maybe in the 3-4 pound range) and be durable. I'm insulating the oven with 8# FiberFRAX blanket and am certain I'll have enough "left over" to build a door. I'll just need to plan on that feature when I develop the entry opening to give myself something flat to seat and seal to. Initially I was thinking about a flush mounted door stuck to the face of the oven, but, I'm not really stuck on any one design so things change from day to day.

[dmun]

Re: Oven Door? Insulated or not. Pros & Cons

I think the quick cool-down time on the primavera is a matter of mass. It's small in diameter, and may have half a ton less heat-sink material surrounding the chamber than some of our 4 1/2 inch thick pompeiis.

[david s]

Re: Oven Door? Insulated or not. Pros & Cons

Check out the kind of fiber in the FB board. You don't want nasties floating around there, or you can encapsulate the board completely.

[Stan]

Re: Oven Door? Insulated or not. Pros & Cons

RT,

I'm not sure how much insulation it has. I know it's those high density FB blankets, and I know the outside of the oven gets warm but never hot. The door, on the other hand, reads around 400+ degrees sometimes.

Stan

[RTflorida]

Re: Oven Door? Insulated or not. Pros & Cons

Stan,
Thats quite a drop in 12 hrs. If I put my steel door in place shortly after pizza (say, 8-9 pm), at 10-11 am the next morning I will be somewhere in the 350 degree range.

With the insulated door and the same scenario, the oven will be at 450-475 the next morning.
Just curious, how much insulation does a Primavera have?

RT

[Stan]

Re: Oven Door? Insulated or not. Pros & Cons

I've wondered about door insulation myself. I have a Primavera oven with a steel door. No matter how long or how hot I fire the thing, I CANNOT cook with retained heat the next day. I know the insulation in the oven is working, and all I can figure is that I'm losing massive amounts of heat out of the steel door via conduction. We're talking a 900+ degree oven dropping to 150 in 12 hours. I'm going to do some door insulating experiments this summer and see what kind of improvement I get. I was thinking of just sawing some FB insulation board to size and sandwiching it between the original steel door and a piece of cut aluminum.

Stan

[david s]

Re: Oven Door? Insulated or not. Pros & Cons

Hinged doors on kilns are usually the fist thing to fail as the kiln ages. They just don't give a positive seal when old and the steel usually rusts badly due to the heat. The bigger the oven the bigger and heavier the door.

[RTflorida]

Re: Oven Door? Insulated or not. Pros & Cons

An insulated door does not have to be a "heavy plug" as you mention.
I made both - a heavy steel door (1/4" boiler plate, solid steel handles, and heavy steel support legs) and a lightweight insulated plug (sheet aluminum over a frame of aluminum angle "iron", then filled with perlite, with aluminum handles). Both were painted black with high heat paint 3 yrs ago and still look great. Since I have no welder of any kind, both are assembed with stainless screws or bolts.
The steel door looks great, rugged, heavy duty.....but it weights 15 lbs, I have chipped so many bricks I've lost count.
The insulated door only weights 4 lbs 2 oz. and is self supporting and does not need legs. (2 1/2" thick).

I think your wife could easily handle a 4 lb door....based on feel, I thought it was only 2-3 lbs....put it on a scale to confirm. Really works well in comparison to the steel, if you are looking to retain heat for a long period.

RT