LITE WATE insulating concrete instead of Vermiculite?

[Michael Thomas]

Hi,

Can I use this LITE WATE 23/58 insulating concrete for the dome and hearth instead of vermiculite? I've attached the specifications. The thing that I notice is that the thermal conductivity is 1.9 at 1500F.

Best,
Michael

[david s]

At $100/30 lbs, I'd be making my own vermicrete. Can't read the table you provided but you could compare it to this.

[Michael Thomas]

Thanks David! Interesting; how do you make your own? Is the gardening vermiculite a similar compound/product?

[Michael Thomas]

is this the perlite that I can use to make insulating concrete? Its a gardening product but its description seems similar to perlite that is describe for insulating concrete (porous etc)

https://kent.ca/9-l-promix-perlite1024278

[UtahBeehiver]

Just search the forum for perlite or vermiculite, there are hundreds of post on this subject, ratios, suppliers, etc

[david s]

You can use either perlite or vermiculite. I've found a mix of half of each seems to give better workability than either of each alone. There are different grades (grain size) available. Not much difference in the end result but the finer grade makes workability a bit easier although it requires more water when making up the mix and that water requires removal. So I go for a medium grade of both. When making up a mix for every 10 parts by volume of aggregate it requires 3 parts water. If making a lean mix the addition of a little powdered clay helps workability, say a handful for every litre of cement added.

[Michael Thomas]

Thanks UtahBeehiver and david s! Sorry, I wasn't being clear. I'm wondering if there is a substitute for vermiculite or perlite since LITE WATE is the only cost effective stuff that I can find (at 80 USD per 55 lbs bag), which doesn't seem to have sufficient thermal heat capacity. Does the difference in Thermal conductivity I showed make a big difference? I can't seem to find any cheap vermiculite or perlite locally (if I lived in Ontario it'd be easier) and I'm hoping to avoid shipping.

[david s]

For an insulator you don’t want thermal mass. Vermiculite and perlite are used extensively in nurseries. Try nursery suppliers and hydroponics supplies.

[Michael Thomas]

Thanks again. Does the difference in thermal heat conductivity (K factor) make a difference? The difference is: 0.65 - 0.75 (vermiculite) vs 1.9 (lite wate).

[david s]

Hi Michael,

I couldn't; read the unit of measurement in the table you provided for the Lite wate insulating castable, but I'd suspect it would be similar to a vermicrete or perlcrete mix. The unit of measurement is often different as there are R values K values and BTU's as well as Watts/metre kelvin, it can get confusing. The greater the cement content the higher the density and correspondingly lower the insulating value will be.So if you want the insulation layer to have maximum insulation you need a lean lightweight brew. The drawback is that the leaner you go the greater the difficulty in application because it becomes less workable and its strength is also reduced. Studying the table explains it.

[Petter]

Thanks again. Does the difference in thermal heat conductivity (K factor) make a difference? The difference is: 0.65 - 0.75 (vermiculite) vs 1.9 (lite wate).

You need 3 times as thick insulation layer with the lite wate to get equal insulation properties.