Insulation Blanket Question

[NanyukiTom]

Hi All,

I'm about to embark on a 42" Pompeii oven. I've assembled all the materials but I'm having trouble finding anything readily available in Kenya to use as the insulating blanket between the brick dome and the vermicucrete insulating layer (I'm building an igloo design). Does anyone have any suggestions about what to use? Can I eliminate the the insulation blanket and just beef up the vermicucrete layer? There is a vermiculite mine just near Nanyuki and I can get as much vermiculite as I need. My impression is that the insulation blanket serves as a sort of expansion joint as well as an inulsation blanket and that building the vermicucrete layer right on the bricks will result in cracking sometime in the future. Can I just leave a 1/2 air space and be done with it? Any advice will be apprciated.

Thanks

[asudavew]

Originally Posted by NanyukiTom

Hi All,

I'm about to embark on a 42" Pompeii oven. I've assembled all the materials but I'm having trouble finding anything readily available in Kenya to use as the insulating blanket between the brick dome and the vermicucrete insulating layer (I'm building an igloo design). Does anyone have any suggestions about what to use? Can I eliminate the the insulation blanket and just beef up the vermicucrete layer? There is a vermiculite mine just near Nanyuki and I can get as much vermiculite as I need. My impression is that the insulation blanket serves as a sort of expansion joint as well as an inulsation blanket and that building the vermicucrete layer right on the bricks will result in cracking sometime in the future. Can I just leave a 1/2 air space and be done with it? Any advice will be apprciated.

Thanks

The insulating blanket is a better insulator, so less vermcrete is needed.
So it's no problem at all substituting more vermiculite instead of a blanket.

No problems at all.

Check out this thread. It should help you with the amount of vermcrete you will need.

http://www.fornobravo.com/forum/f6/i...iency-218.html (Insulation Efficiency)

Good luck,

Dave

BTW - We love pictures!
If you are able, post away!

[jeff]

NanyukiTom.
You have a vermiculite mine close by?
Lucky bastard, (apart from the chance of asbestosis, I guess.) Australia imports most vermiculite from Africa I believe, although a source from near Alice Springs is supposedly up and running.
Mate, Dave (asudavew), helped me out, as in days ago.
Between his advice and your own gut feelings, how big a stuff-up can you make? Seems that 1" of ceramic blanket= 2" vermiculite. So it becomes a trade-off between space and finances.
In your situation, seems like the cash could go to a damn fine wine with the first meal from the oven.
Anyway mate, enough BS. May 2008 treat you well.
Peasant Jeff.

[asudavew]

I have a 1/2 inch of blanket topped with about 6 inches of dry vermiculite and perlite.

I fired my oven on Saturday night for pizza.
Sunday night about 7:30 pm, it was still 350f and I put a pork loin in.
About an hour later the loin was at 165f and tasty as can be.

So the more insulation the better!


Dave

[Frances]

Hi NanyukiTom,

I believe the original oven plans on this site had only a Vermiculcrete layer over the dome for insulation. The Vermiculcrete is a whole different thing from Concrete, it feels like cork when its finished, and I never read anything on the site calling for an expansion joint when using it as insulation.

So I'd say if you can get it easily and at low cost, go with it!

Frances

[gjbingham]

6 inches of vermicrete will do it according to my readings.