Draft door help Design Styles, Chimneys and Finish Discuss Draft door help in the Pizza Oven Design and Installation forums; I am trying to have the effects of a vent/draft door (in order to have a "bellow" and create a ...

[masuzzu]

I am trying to have the effects of a vent/draft door (in order to have a "bellow" and create a blast of air as id done in wood burning stoves). I am using a "door" (cement board one inch shorter than the actual opening) . I used this at the oven mouth an at the vent mouth with no effect.
I assumed that by allowing one inch of space at the bottom ,the air would flow with much greater intensity,however I noticed no change at all.
What am I doing wrong?
Thanks!

[Jed]

masuzzu,

In your door design, do you have any openings up high in the door?

To create a draft, or to move any air, it must have some place to move to...

If you provide a pathway for air to move into the oven, there must be also an area for the air to move out of the oven at the same time, otherwise, no air movement.

JED

[nissanneill]

Hi Masuzzu,
I agree with Jed,
You must have air flow, both at the bottom and at the top to create a draught. Remeber, that a wood stove's firebox is connected to a flue or chimney and the smoke/gasses escape but you do not see it.
With an oven however, the chimney is outside your dome and you need to pull the top of your door outwards towards your outer arch for the smoke/gases to vent properly.
If you are to make a 'vent door', then you will need 2 slides/gates, one at the top and the other at the bottom. You can then control your fire (albeit reduced because it will be choked somewhat) by sliding either gate to control the incoming or outgoing gasses.
Rhater than making a control door, just pull your normal oven baking (the one that seals the dome opening) away from the dome by an inch or two. This will reduce the amount of heat lost but will also allow the fire to breathe and the amount you move it back will depend by how muchor how little it will breathe.
Give it a try and report back.

[karl]

Mazzuzu,

I used this at the oven mouth an at the vent mouth with no effect

Using your door at the oven mouth should obtain the necessary air/flue pathway and it is strange that you did not notice any improvement. I use the same approach with good effect, but only after the fire has developed somewhat (no door) and the bricks have started to warm up. In paricular the chimney pipe needs to heat up to create good suction. Try to start the fire closer to the exit and the vent to prime the chimney. Then push it back and use the door as suggested.

karl