#1  
Old 12-09-2010, 07:26 PM
Serf
 
Join Date: Aug 2010
Location: Gilbert Arizona
Posts: 15
Question Insulation: Which is first? blanket or concrete

I have finally got the oven built. We are now waiting for it to dry out before insulating.
We are going to have the dome inclosed with exterior walls and ceiling that will consist of stucco and stone. The dome will not be exposed to the outside.
So???
1. Do we cover the oven dome with the FB Blanket, as stated on Page 55 (Pompeii Oven Instructions), then p. 56 cover with insulating concrete?
or
2. Do we cover it with concrete first like what some of the pictures look like(P. 47, 49,) Also, according to the Allen Scott book he used foil first (that was to help with expansion) then put concrete on the foil, then insulation.

It mentions how all the motar and concrete need to dry prior to insulation. So it doesn't make sense to put FB blanket then concrete, cuz i would need to let it dry another week or 2??
Help, Michelle
Reply With Quote
  #2  
Old 12-09-2010, 08:55 PM
Il Pizzaiolo
 
Join Date: Jan 2007
Location: Tampa, FL
Posts: 1,446
Default Re: Insulation: Which is first? blanket or concrete

No need for any extra mortar/concrete. Some have added more for extra thermal mass or as in my case, I wanted a smooth an uniform surface before proceeding with the blanket and vermiculite concrete.

Since you are going with an enclosure, you have a couple of options. Simply fill the entire structure with loose vermiculite or perlite (at least 4" all around, more if you can afford it). Second, you could just use insulating blanket (minimum is 2", but I would go with 3" or 4"). Third, use a combination (2" blanket then pour in several inches of loose perlite or vermiculite).
I would go through the entire curing process before sealing up any oven, you need to let the steam escape (will keep minor cracking from becoming blowouts)

Skip the foil, that whole "slip plane" issue has been debunked. Aluminum foil disolves when left in contact with masonry. It could make a little sense ((if it didn't disolve) if you were building an igloo, but you are not. The blanket actually provides all of the flexing needed to avoid cracking on the exterior of an igloo.

RT
Reply With Quote
  #3  
Old 12-09-2010, 09:38 PM
Ken524's Avatar
Il Pizzaiolo
 
Join Date: May 2007
Location: Kentucky
Posts: 1,649
Default Re: Insulation: Which is first? blanket or concrete

Hi Michelle,

You definitely want to put the blanket on first.

There isn't any harm in putting the blanket and vermiculite/cement on right now. Many folks wait on the vermiculite/cement until after a few curing fires to make sure everything's ok under the hood.

Skip the aluminum foil. From a different discussion:
Quote:
Originally Posted by dmun View Post
No foil! It's useless. It rots out in contact with the caustic portland cement, but before it does it creates a vapor barrier that prevents you from drying out your oven. Stomp out the foil meme.
Good luck curing! Let us know how it goes.
__________________
Ken H. - Kentucky
42" Pompeii


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Updated!


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
...
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
...
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #4  
Old 12-09-2010, 09:39 PM
Ken524's Avatar
Il Pizzaiolo
 
Join Date: May 2007
Location: Kentucky
Posts: 1,649
Default Re: Insulation: Which is first? blanket or concrete

Looks like I spent too much time composing my post. RT beat me to it!
__________________
Ken H. - Kentucky
42" Pompeii


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Updated!


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
...
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
...
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #5  
Old 12-09-2010, 10:28 PM
GianniFocaccia's Avatar
Il Pizzaiolo
 
Join Date: Jun 2009
Location: Disneyland, CA
Posts: 1,373
Default Re: Insulation: Which is first? blanket or concrete

I too have been curious about the relative efficiency of respective oven insulation layers and the optimal R-Value per layer outwards from the dome exterior. Could you put an initial layer of insulating mortar (Kaolite?) on the dome followed by rock wool and vermiculte? Just wondering...

John
Reply With Quote
  #6  
Old 12-10-2010, 06:01 AM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default Re: Insulation: Which is first? blanket or concrete

Quote:
Could you put an initial layer of insulating mortar (Kaolite?) on the dome followed by rock wool and vermiculte?
Insulating castables are very expensive. If you have money to burn, just use extra refractory blanket insulation.
__________________
My geodesic oven project:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #7  
Old 12-10-2010, 10:40 AM
Neil2's Avatar
Il Pizzaiolo
 
Join Date: Oct 2006
Location: Vancouver Island
Posts: 1,374
Default Re: Insulation: Which is first? blanket or concrete

You don't need anything fancy. 4 inches of vermiculite (or perlite) mixed 12:1 with normal Portland cement placed directly on the dome bricks will suffice. (Mix gently so as not to break up the vermiculite particles and thus reduce insulating value). You don't need chicken wire or stucco lath or anything like that.

If you have an enclosure, make sure it is ventilated. Some people just fill up the inside of the enclosure with loose vermiculite.
I went with the igloo shape. If I were building an enclosure, I would still put the 4 inches of 12:1 vermicrete over the dome just to make sure it stays in place.

You could put this on before or after the initial curing - I don't think it matters too much. People have done it both ways with equal success.

Last edited by Neil2; 12-10-2010 at 10:46 AM.
Reply With Quote
  #8  
Old 12-12-2010, 06:33 PM
Serf
 
Join Date: Aug 2010
Location: Gilbert Arizona
Posts: 15
Default Re: Insulation: Which is first? blanket or concrete

Thank you, Michelle
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Laying insulation blanket over dome tfasz Tools, Tips and Techniques 7 07-27-2010 08:19 AM
Need advice on what is the best method when installing the insulation blanket please? Wheels1974 Tools, Tips and Techniques 13 01-28-2010 06:28 PM
Vermicrete over insulation blanket tony007 Getting Started 4 01-09-2010 03:51 AM
Blanket Insulation altamont Pompeii Oven Construction 12 10-01-2009 08:09 AM
Insulation Blanket Question NanyukiTom Newbie Forum 5 12-31-2007 09:45 PM


All times are GMT -7. The time now is 05:42 PM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC