Steel tunnel oven

[Buzzlight]

Hey all! This is my new oven! It's 3/4" thick steel pipe. Left at my house when we moved in. I think maybe a sewer pipe but hopefully never used!
anyway, started a few small fires so far and had a few issues. Looking for advice....
First couple burns I can't seem to get it hot enough. They were small burns but I could touch the front firebricks.
Also when I close the door, the fire almost goes out. When I open the door, tons of smoke. Cough cough.
Anyway, thoughts? Could a steel tunnel still need insulation and cement? Do I need to try a bigger fire?
Excited to start making pizza in the thing!

[Gulf]

Hi Buzzlight,

Welcome to the forum. I see lots of issues with your oven. Here is a search of the forum for steel ovens. Most all opf your questions have been addressed in some of those threads. But, closing the door is robbing your oven of air. Air is needed for combustion.

[Buzzlight]

Thanks, that's a great thread. Lots of ideas to consider but if you feel like typing...what are some issues you see at first glance of this photo?
It is something I completely made up with no plans, so I fully expect to modify it! It's all reclaimed materials and was a bit of a family project this summer.

[Gulf]

There should have been several threads in my link. I'll have to go back and check.

.....what are some issues you see at first glance of this photo?

Possibly, no insulation under the cooking floor.(that would be a bummer imo)
The flue is not separated from the cooking chamber.(Allows heat to escape)
A masonry jacket and insulation around the steel cooking chamber. (for heat retention.)

You did not address my concerns that you were smothering your fires with the door? If you can't get a proper fire going, you can't heat it up!

[Buzzlight]

the door use was more of an experiment. I kept it open mostly during these couple of burns, but closed it for brief periods to see what happens. I totally get that it smothers the flames, but is that normal, or is the chimney supposed to allow enough air to flow in and out that closing the door is ok. Do people normally cook with the door open?
Also I did realize that the door is supposed to be smaller than the chamber. I still may be able to address this.

[UtahBeehiver]

I will add one more, steel (and this pipe is 3/4" thick) really transmits the heat away from the oven, even if insulated on the outside to slow the heat transmission down it will still happen. For example, the K value (thermal conductivity) for steel is around 30-40 depending on carbon content, where as a standard fire brick is 0.47 (higher the number the more heat transfer occurs), CaSi inuslation, commonly used over a brick dome is 0.05. So the dome is acting like a huge heat sink and even if you get to the temps you need is draws off very quickly. The same holds true if the floor is not insulated. You do not say what the floor is and if insulated. Plus one on Gulf's comments.

Since you said you winged it, I suggest you download the "free" eplans from Forno Bravo retail site and read through it. It goes over design and construction of ovens.

[Buzzlight]

sadly the floor is not insulated. It's 3" of concrete and then 1.25" fire bricks on top of that.