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-   -   Pompeii Oven Insulation (http://www.fornobravo.com/forum/f8/pompeii-oven-insulation-18187.html)

Bubazineti 08-07-2012 05:52 AM

Pompeii Oven Insulation
 
Hi all,

I am nearing the end of my build.

Over the dome I have 1in Kaowool ceramic blanket held on with chicken wire. On top of that I have 2 to 3 inches of high heat mortar. Against my better judgement I didn't add 4" of vermiculite around the blanket and am worried that I have insufficient insulation.

I am located in Queensland, Australia so apart from a couple of months in the year it is pretty warm.

Having spent so long the last thing I want is it not to function properly so my question to those in the know is will this be enough or should I invest in another layer of blanket or (shudder) 4" of vermiculite. The finish on the high heat mortar is pretty close to perfect - it just needs a layer of stucco / render. If I can get away with what I have it would save a lot of dollars on blanket and more high heat mortar.

Thanks in advance,
Luke.

REE REE B 08-07-2012 08:59 AM

Re: Pompeii Oven Insulation
 
Hi Luke

Your Ceramic Insulation blanket is enough so no worries at all.

Enjoy finishing off your oven :)

moderator 08-07-2012 09:06 AM

Re: Pompeii Oven Insulation
 
Hi Luke,

Thank you for your question. We recommend 3" of the insulating blanket covering the dome. When insulating your pizza oven you either, use the insulating blanket or vermiculite, not both. If you have anymore questions... ask away!

Amber

REE REE B 08-07-2012 09:33 AM

Re: Pompeii Oven Insulation
 
Hi Luke

Do you have the Pompeii 90 or 110 kit? The Pomeii 90 kit requires 2 blankets and the Pompeii 110 requires 3 blankets. So you may just need one more blanket to finish the job.

Bubazineti 08-08-2012 01:17 AM

Re: Pompeii Oven Insulation
 
Hi guys,

I'm actually not using a kit. I used the pompeii oven instructions but interpreted them as either blanket or 4" vermiculite. On rereading them and looking at other forum posts i'm concerned I should have added more insulation.
The oven is 42" internal.
Dome is constructed using half firebricks with high heat mortar.
Wrapped in 4m of kaowool s and 2m of a better blend of kaowool.
2-3"of high heat mortar to form the dome.

On coming back from work today it turns out the father-in-law has been a bull at a gate and put a fire on despite me only mortaring on Sunday. It's a medium size fire - much hotter than it should have been for a first burn and its put a split in the mortar covering the arch in front of the chimney. This part is warm to the touch.

The front part of the dome behind the chimney is slightly warm to the touch (where the kaowool s is) and the top and rear is cold (where I put the higher quality kaowool).

So i'm going to have to do a repair job to the arch mortar and maybe add some insulation to it as I didn't have enough to cover the front 8" in front of the chimney.

Hope this makes sense.

Cheers,
Luke.

Edit
My wife has suggested that the heat may be coming from the chimney. The inside of the door arch is made of curved iron with a welded chimney so this must be getting superheated and possibly radiating out and heating the high heat mortar on the surface. Just an idea.

brickie in oz 08-08-2012 02:49 AM

Re: Pompeii Oven Insulation
 
High heat mortar isnt insulation.

Bubazineti 08-08-2012 03:28 AM

Re: Pompeii Oven Insulation
 
Hi brickie,

Yep i'm aware of that. The question was whether 1" of ceramic blanket is enough.
The cerachem 1430 (better quality ceramic fibre) seems to stop the heat getting to the exterior with the fire today (though I haven't done a full strength fire yet) while the kaowool s is letting a lot of heat through.

So I guess the reality is (unless the heat is radiating from the metal chimney through the surface mortar) I need to put another layer of cerachem 1430 on and make sure I insulate the arch (another 6m at $30/m :().

Cheers,
Luke.

dottavio 08-10-2012 12:56 PM

Re: Pompeii Oven Insulation
 
Not sure which version of the Pompeii instructions you have, but it calls for 3" of ceramic blanket or 1" cermanic blanet with 4" insulating (perlite or vermiculite) concrete.

Doug O

Faz 08-11-2012 12:31 AM

Re: Pompeii Oven Insulation
 
You will get some extra heat dissipation during your drying fires, as the steam will carry heat from the bricks through to the outer covering. I do not think, however, that 1" of blanket is anywhere near enough insulation, especially as you have built in a huge heat sink with the 3" layer of mortar on the exterior. Heartbreaking as it may be, I'd recommend stripping off that external layer and adding more insulation (blanket or vermicrete), otherwise you'll struggle to maintain any temperature in the oven.

Bubazineti 08-11-2012 04:03 AM

Re: Pompeii Oven Insulation
 
That is bad news - you don't think i'd get away with just laying some more insulation over the fireclay?

Think i'll have to go vermiculite even though it's a nightmare to use. 2 more layers of ceramic blanket would be $400. I shudder to think how much this has cost to this point. Should have stuck to my guns and done it in the first place. While i'm about it going to cut out the iron flue and put in a stainless 8" (if I can find one).


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