insulation stupid question

[jolani shrinski]

I am in the tropical area of Hawaii. REMOTE. Why do I need insulation.?

[Greenman]

Re: insulation stupid question

No such thing as a stupid question.

You need insulation under your oven to minimise the escape of heat through your slab and over the top of the dome to maintain the heat within the thermal mass created by the material in your dome and hearth.

It also stops others being burnt by extreme heat on the outside of the dome bricks.

Think of it as trying to isolate the hearth and dome. Regardless of how hot it is outside it will be a lot hotter inside that oven, if you are using it.

[Tscarborough]

Re: insulation stupid question

Unless you are in the volcano, ambient will be 700-800 degrees less than your oven.

[wotavidone]

Re: insulation stupid question

Insulation is about keeping as much of the heat you generate from your fire wood as you can. Strictly speaking, you don't need it, in the sense that you can cook a pizza in an uninsulated oven.
That's the simple answer, here comes the complicated one.

If you want to bake bread in your oven tomorrow after a pizza party tonight, without lighting the fire again, you need insulation to help retain all that heat you pumped into the bricks.
If you want to make 90 second margheritas with crispy crusts, you need insulation to help you attain the very high temps involved.
The better the insulation, the quicker your oven will reach pizza temps, and the less wood you will need to do it.
I've built an oven with lesser quality insulation and a thin shell and it works well. I have a pizza party, wait about 3 to 4 hours with the fire removed and the door open, then bake a batch of bread.
I helped my mate build an oven with 6 inches of aerated concrete all round - under the floor and over the top, with any voids between his round dome and square enclosure filled with loose perlite.It's brilliant for having a pizza party tonight, bacon and eggs tomorrow morning, followed by a batch of bread.
My advice is, even if you doubt the need, put in insulation, especially under the floor.
If you build the oven then decide you want to insulate it, you can do the dome easy. If you haven't put it under the floor before you build, it's near enough to impossible to put in later.
I see you live in Hawaii.
Would scoria or pumice be easy to obtain? At the least, mix the concrete slab that goes under your floor bricks yourself, using scoria or pumice for the large aggregate (gravel) portion of your concrete mix. That will at least insulate the floor to some degree.
If you can also substitute fine scoria or pumice for the sand used in a normal concrete mix, that too will improve the insulation qualities.

[Gulf]

Re: insulation stupid question

I am in the tropical area of Hawaii. REMOTE. Why do I need insulation.?

I would gladly come and devote a few minutes a day, for two whole weeks of my precious time, to consult you on your build for just room and meals .

[UtahBeehiver]

Re: insulation stupid question

Gulf, I remember Annette Funicello and all those beach movies................

Jolani,

What part of Hawaii, I have family in both Oahu and Maui.

[jolani shrinski]

Re: insulation stupid question

Big island upper Puna

[Tscarborough]

Re: insulation stupid question

I remember Annette from the Mickey Mouse club. Wait. Did I say that out loud?

[cobblerdave]

Re: insulation stupid question

G'day Tscar
Bet you had a crush on her as well
Regards dave

[Greenman]

Re: insulation stupid question

Showing your age fellas. Next thing you will be telling us that you still have the Mickey Mouse Club gear stashed away, or find yourself humming the Club song.

Sadly she died last year at the age of 72, which makes her fans .................

..........hold the banner high!!

[david s]

Re: insulation stupid question

I am in the tropical area of Hawaii. REMOTE. Why do I need insulation.?

We live in the tropics too and I suspect that the heat loss would be marginally less in high ambient temperatures. But your ambient temperature is nowhere near your internal 400 C and as heat wants to travel from hot to cold, then you need insulation.

[UtahBeehiver]

Re: insulation stupid question

Humming - M...I...C...K...E...Y...............M...O...U...S. ..E.

Jolani,

Here is a link I found on a build using lava rock. Note he still insulated with CaSi blanket.

Wood Fired Lava Brick Oven

[JAG]

Re: insulation stupid question

Tscar, at least you remember

[Gulf]

Re: insulation stupid question

Humming - M...I...C...K...E...Y...............M...O...U...S. ..E............

That's funny Russell,
What's rolling around in my head is the tune to Beach Blanket] B...I...N...G...O

Edit:
Jolani,
Very sorry for the hijack .

[kanoer54]

Re: insulation stupid question

Good to know other oven builders are in the same age bracket as me. Guess we all like to have fun and still keep a serious side.

Yes, you should insulate, insulate, insulate.

jon