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-   -   Mineral Wool/RockWool (http://www.fornobravo.com/forum/f6/mineral-wool-rockwool-14374.html)

azpizzanut 09-15-2010 03:05 PM

Mineral Wool/RockWool
 
Hello All,

It was hard to find, but I finally found mineral wool batts in a variety of thicknesses. It is available from an insulation contractor in Phoenix, Arizona. It comes in 4lb and 8lb density. I plan to use the 2" thick batts since it will be easier to form over the igloo dome, I'll use two layers. That should allow me to smooth out lumps before covering with chicken wire mesh. I take it from comments made on the forum that the 8 lb density is the best choice. Correct?

The oven manufacturer recommends a layer of insulating refractory concrete over the precast oven panels. They supplied four bags with the kit. I want to cover the insulating concrete with 4" mineral wool then a layer of vermiculite concrete mix. Then a layer of stucco, then paint as a weatherproof barrier. Is this sequence reasonable? Any recommendations before I begin casting insulating concrete for the hearth firebricks? Construction should go fast after the hearth is laid since the oven panels are precast in sections.

By the way, I contacted the oven manufacturer with questions on finishing the oven beyond the initial layer of insulating refractory concrete and was informed that the company is in the business of casting the parts and wouldn't recommend a finishing sequence. "Contact a mason". I've already exceeded my oven budget so won't be hiring a mason. I hope to get some ideas from forum members.

Cheers,

C5dad 09-19-2010 07:37 AM

Re: Mineral Wool/RockWool
 
Hey azpizzanut - which contractor has the mineral wool? my normal supplier dried up.

CW

azpizzanut 09-19-2010 08:58 AM

Re: Mineral Wool/RockWool
 
Border Construction specialties.

SCChris 09-19-2010 09:42 AM

Re: Mineral Wool/RockWool
 
The lower density, 4lb, should provide a greater R-Value but less support for the Vermicrete. I tried to look up the R-Value difference, but didn't imediately find it. Your vendor will be able to tell you this. The lower density should also be a bit easier to form, less material, more air, it should more flexable everything being the same.



Chris

PS I've rooted around the net and don't find Density / R-Values. Ask your evndor and please let us know what you find. Thanks!

azpizzanut 09-19-2010 10:39 AM

Re: Mineral Wool/RockWool
 
Thank you, SCChris.

Less support? Yes, I see your point. Maybe use a heavier 2" chicken wire mesh or possibly a 1" chicken wire and two layers of rock wool, each held with the wire. I don't mind doing the extra work. Is there something other than hexagonal wire to hold rock wool?

I was able to find R value information for rock wool vs fiberglass. They are about the same except rock wool ,being denser per cu ft, is the better barrier to sound. One site gave the value of 2.5lb density rock wool as R-3.7 per inch thickness and R-3.9 per inch for 4lb density. If we extrapolate, then the 8lb density would have even higher R value, though not twice that of 4lb.

Only one manufacturer uses a liquid ablative to coat their rock wool product. The others do not, according to a website. I've learned a lot about rock wool in the past ten minutes thanks to Google.

Cheers,

SCChris 09-19-2010 04:22 PM

Re: Mineral Wool/RockWool
 
I don't know that support for the vermicrete would be a problem at all. Many of those making igloo style ovens are running the vermicrete right over the ceramic fiber blankets and this would have much less support for this layer. Best to you!

Chris

Storm Runner 12-16-2010 12:35 PM

Re: Mineral Wool/RockWool
 
Quote:

Originally Posted by azpizzanut (Post 99432)
Thank you, SCChris.

I was able to find R value information for rock wool vs fiberglass. They are about the same except rock wool ,being denser per cu ft, is the better barrier to sound. One site gave the value of 2.5lb density rock wool as R-3.7 per inch thickness and R-3.9 per inch for 4lb density. If we extrapolate, then the 8lb density would have even higher R value, though not twice that of 4lb.

Cheers,

I was looking around and found that the R-Values of the fiberglass and the Rock Wool are about the same, with the Fiberglass being a bit higher per inch. 0.5 at most

The main difference between the two is the melting point with fiberglass melting at a considerably lower temp and ceramic having a much higher melting point.

Material Temperature
Glass wool 230 - 250 C (445-480 F)
Stone wool 700 - 850 C (1290-1560 F)
Ceramic fibre wool 1200 C (2190 F)

C5dad 12-17-2010 01:44 PM

Re: Mineral Wool/RockWool
 
Nice thing about the vermicrete is that it is fairly light, so should not compress the insulation unless you press down.

Lburou 12-17-2010 05:49 PM

Re: Mineral Wool/RockWool
 
When I was young ;) rock wool was available as loose fill, much like vermiculite is today. Is it still available in that form today? In that form, it should be easily adaptable to our WFO projects.

:)

C5dad 12-17-2010 06:08 PM

Re: Mineral Wool/RockWool
 
I have nto seen it in the loose form, though if you get ahold of the company mining and processing it, I bet you could get it as loose fill!


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