Oven opening size

[madhatter1138]

Re: Oven opening size

Glad to hear this! Since its arched from 9" (not 9 1/2" like I said earlier) to 12" I can take comfort in the math that it averages out 10 1/2" of height..which is right on the money

[david s]

Re: Oven opening size

Don't sweat. It makes far less difference than many people would lead you to believe. Just fire your oven as it is, you'd find no noticeable difference if you rejigger it to 63%

[madhatter1138]

Re: Oven opening size

Building a 32" oven. Dome height is 16". Oven opening is arched. 12" in the centre arched to 9 1/2" to the sides. Width is 18". I'm worried that height (at 75%) is way off the mark. Should be around 10.5"...BUT if I add a row of half block then it gets really tight on the ends...
Any thoughts? Apparently I missed the 63% rule in the plans!? I figured it was ball parked etc etc...

I only looked into this today after completing the arch and it just looks to big....

[david s]

Re: Oven opening size

Ok, I think it's 8x5 inches at the moment. So I may have to open it up a little as mine is a 39 inch oven.
Here are the pictures of my opening. Does it all
Look about right?

That's ok, just make the cross section of the chimney a little bigger. The restriction at the bottom where the smoke enters will just work as a venturi making the smoke accelerate at that point.

[FrankHawkins]

Re: Oven opening size

From another angle.

[FrankHawkins]

Re: Oven opening size

Ok, I think it's 8x5 inches at the moment. So I may have to open it up a little as mine is a 39 inch oven.
Here are the pictures of my opening. Does it all
Look about right?

[david s]

Re: Oven opening size

Cheers thankyou!
Also I'm building the chimney vent out of bricks. What size would be best to make the internal diameter of it.

Depends on the size of your oven.
A 24" oven needs 20 sq in
A 30" oven needs 30 sq in
A 42" oven needs 50 sq in

[FrankHawkins]

Re: Oven opening size

Cheers thankyou!
Also I'm building the chimney vent out of bricks. What size would be best to make the internal diameter of it.

[david s]

Re: Oven opening size

I've found the correct ratio of water is 3 parts water for every 10 parts vermiculite, although if you have the fine grade you need more water. As the addition of cement decreases the insulating capacity drastically I use a 10:1 mix, vermiculite, cement. Any less cement than this makes it difficult to get a good workable mix. Adding a little powdered clay to the mix will help to make a lean mix more workable.

[Greenman]

Re: Oven opening size

Hi Frank - The 'vermicrete' insulation is just vermiculite and cement. A ratio of 8:1 by volume works ok.

The trick is to get the moisture level right and too much water is an issue. It will end up like wet rice bubbles and is not a 'fun' material to work with. I found that working from the bottom up, balling it up and applying it in one 'smear' and moving on worked for me. Messing with it after you place it caused grief in the form of crumbling away.

I had chicken wire over the blanket and it helps hold the vermicrete too. It is perfectly stable once it hardens but I found it an 'interesting' medium. I did, however, use it on subsequent builds.

By the way, it is best to mix it in a barrow with a hoe rather than a mixer. The vermiculite maintains its integrity that way and you can better judge the moisture level. Good luck with it.

[FrankHawkins]

Re: Oven opening size

Cheers, pictures were really helpful!
My next question is about the vermiculite insulation that I will be costing around my insulation blanket. Do you just use cement and vermiculite or do you add sand?
What ratios also?

[yorkshireknight]

Re: Oven opening size

Hi again Frank hope these pics help you to see your idea os recess and chimney.
YK

[yorkshireknight]

Re: Oven opening size

Hi Frank,
Your oven is looking great.

Your idea seems to be exactly as I did mine. A slightly large opening into the vent area will allow for a recess to put a metal door up against it. Great!
your chimney will sit on top of your vent, so yes all sounds good.
Looks like you are over the hard part and not far from completion. good luck and well done!

Paul aka Yorkshireknight

[FrankHawkins]

Re: Oven opening size

Hello guys. Here is my pizza oven so far....
Once I finish the dome, I will be building the front entrance.
I was going to make this slightly wider and slightly taller than the entrance in the photo so that I can push a metal door up to it.
I was also going to build my chimney into the entrance chamber.
Does this all sound about right?
Interested to hear any feedback!
Thankyou!!

[yorkshireknight]

Re: Oven opening size

Hi CRR,

IMHO the opening door seems a little small, most builds go for approx. 63% of the dome height.
If yours is 26 inches high then 63% =16- 17 inches.

your width seems to be quite narrow too Make the width usable.

I only had a 16inch high oven but my door opening was 101/2 inches high by 16 inches wide and it works great
I cannot imagine working with an opening and narrower than what I have which may restrict you getting stuff in and out as well as poking the fire.

Have you now completed the door? If not then do a little mock up of the opening and try to place the largest pot you may use or a pizza paddle just to get a feel for workability.

Others may advise about the air flow too, but not being an engineer, I shall leave that up to those in the know.

Good Luck
YK