Forno Bravo Forum: The Wood-Fired Oven Community

Forno Bravo Forum: The Wood-Fired Oven Community (http://www.fornobravo.com/forum/)
-   Finding Building Materials (http://www.fornobravo.com/forum/f44/)
-   -   Alternative Insulation (http://www.fornobravo.com/forum/f44/alternative-insulation-18897.html)

NeilB 01-31-2013 06:44 AM

Alternative Insulation
 
Hello cooks and cobblers!

I am attempting to build a wood fire oven in Uganda (part 2?). I live in Kampala, the capital city, and building materials are a bit easier to find than the other East African threads I've seen here. However I'm having trouble finding vermiculite or perlite. Ironically Uganda has a mine which produces vermiculite for export (an australian company) however I've been in touch with them and they have informed me the mine has ceased production and they can't provide it to me.

I've seen other suggestions here like woven ceramic but so far I haven't had luck in finding that in Kampala either.

I'd appreciate suggestions of more commonly available materials that could function as decent insulating material.

Thanks!

TropicalCoasting 01-31-2013 02:36 PM

Re: Alternative Insulation
 
People have traditionally used straw, sand, clay and sawdust for insulating kilns.
There was talk of using lava stone "scoria" in the cement mix hear too.
If you enclose your dome you can use glass bottles on top or anything that wont melt but traps air.

wotavidone 01-31-2013 04:05 PM

Re: Alternative Insulation
 
Scoria, or pumice if you can get it. Lots of air holes in those little rocks, and when you make concrete with scoria as the coarse aggregate, the air holes get sealed over by, but do not fill up with, the cement and sand paste. It worked for me. My floor sits on it, the dome is covered with vermicrete, I seem to have no trouble getting the floor very hot.
Failing that, the dome could be covered with a mix of sawdust and clay, when the sawdust burns away you have aerated clay insulation.

brickie in oz 01-31-2013 09:51 PM

Re: Alternative Insulation
 
Quote:

Originally Posted by TropicalCoasting (Post 144810)
you can use glass bottles on top or anything that wont melt but traps air.

Sorry but I still fail to see how glass bottles can thermally insulate, if you heat glass up it glows until it melts, each adjacent bottle would also get hot and so on.
In the end you would end up with hot glass bottles sucking all the heat away.

Or am I missing something? :confused:

Laurentius 02-01-2013 12:05 AM

Re: Alternative Insulation
 
No, You don't miss much. I stand corrected, you miss, misinformation.

brickie in oz 02-01-2013 12:11 AM

Re: Alternative Insulation
 
Quote:

Originally Posted by Laurentius (Post 144829)
No, You don't miss much. I stand corrected, you miss, misinformation.


What the....? :o :)

Laurentius 02-01-2013 02:16 AM

Re: Alternative Insulation
 
Quote:

Originally Posted by brickie in oz (Post 144831)
What the....? :o :)

It means that your statement is true. It means the glass bottles have proven to be a good insulation in the construction of so call earth houses, thick walled(1&2 meters thick) adobe houses, using, straw, bottles, shredded car tires and other things to trap air pockets for insulation. The misinformation is that the insulation properties of those thing applies across the board to heaters, kiln, ovens and furnaces.

david s 02-01-2013 02:24 AM

Re: Alternative Insulation
 
[QUOTE=
If you enclose your dome you can use glass bottles on top or anything that wont melt but traps air.[/QUOTE]

It is the air that does the insulating. The volume of air inside the volume of a bottle is way more than the volume of the glass. Plus you get extra air spaces between the bottles. It is all about the resulting density of the layer. Glass is not a great insulator on its own but add a large quantity of air to it and it becomes a good insulator. Fibreglass insulating batts, which are made of glass are another good example. Likewise ceramic fibre blanket which uses clay fibres separated by air.neither glass nor clay are wonderful insulators but when combined with lots of air they are.
If you have free bottles then you have free insulation.

TropicalCoasting 02-01-2013 06:34 AM

Re: Alternative Insulation
 
A mate built a corrugated iron ring around his dome and filled it full of stubbies over 1 metre high over the dome.
His oven definitely holds its heat

Laurentius 02-01-2013 10:28 AM

Re: Alternative Insulation
 
Quote:

Originally Posted by david s (Post 144835)
It is the air that does the insulating. The volume of air inside the volume of a bottle is way more than the volume of the glass. Plus you get extra air spaces between the bottles. It is all about the resulting density of the layer. Glass is not a great insulator on its own but add a large quantity of air to it and it becomes a good insulator. Fibreglass insulating batts are another good example. Likewise ceramic fibre blanket which uses clay fibres separated by air.

Why can't you just make a Void, its full of air?


All times are GMT -7. The time now is 10:24 PM.

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