For experts and/or experienced builders!

[C5dad]

Onyxx

Seeing that you are in the 3rd world, go out and find an old oven or three and salvage the insulation from inside. Otherwise, the pearlite and vermiculite will be the cheaper options - yes it is manufactured and sold in Argentina. You can also check around for the folks who have industrial kilns and see where they get their supplies. Lastly, check around for the brick manufacturers, chemical plant or power plants and ask for the Plant Engineer - ask where they get their insulation.

Hope this helps

[pfj_defender]

Hi Folks - been lurking for a few weeks and thought it was about time I dipped my toe in.

A couple of points - I always thought sand was a good insulator. Its resistance to thermal conductivity is 5 or 6 times better than glass. I understand that glass with a vacuum is a good insulator as in double glazing but surely when air can move it will just carry the heat around the glass and move the heat in that way.

There may be another option in a material that is used in Hydroponics - we call it Hortag or LECA and it's a "compressed clay aggregate" (see LECA for an explanation). I'm considering using it for an alternative to vermicrete (in my first oven build) as it should give me a more solid mix compared to perlite or vermiculite. Has anyone ever used this material and what were your experiences?

Paul

[dmun]

There's been some discussion of LECA here, but I don't know if anyone has reported back about how it works. It seems like it would work like perlite, but no personal experience on my part.

[azpizzanut]

Hello,

I searched for LECA and found some information about how it is made and some agricultural and industrial uses. Most of it is used dry. It looks like roasted coffee beans in some of the photos but the size is described being 2mm to 16mm (diameter). It is used in place of soil as a growing medium and as a substitute for perlite and vermiculite regarding hydroponics. Most of the references were from U.K. sources.

I'd be interested to know if LECA will bind with Portland cement to provide a moldable insulation. The difference I see is that there is a lot of space between the individual particles where as vermiculite and perlite have "fines" in the mix. LECA seems quite expensive if you buy it from a hydroponics dealer. It might be good as a filler around an oven instead of dusty perlite or vermiculite. It seemed cleaner in that regard.

Cheers,