kaowool vs insulfrax vs non-ceramic blanket vs insulfrax/vermiculite

[fsucpa]

can someone comment on the relative costs of using extra layers of insulfrax vs insulfrax and vermiculite. In addition, could someone also comment on the use of insulfrax vs kaowool, which is also a ceramic blanket,vs " Safe" non-cermic blanket, described as "This is the "Body Fluid soluable" non-ceramic fiber blanket" "This Roll is the Superwool 607 Max product rated at 2192 F degrees continuous use". this stuff seems to be half the cost of the kaowool.

thanks,

Tom

[asudavew]

If it's rated for over 2000 degrees, I don't think there should be a problem.

Of course I'm not expert, by any means.

[fsucpa]

I think I must have jumbled too much into that question. Let me clarify.

1. If forno bravo sells isofrax ceramic blanket, someone must think its better than kaowool ceramic blanket. Is there much cost differential between the two? Is there much performance differential?

2.How about the non-ceramic fiber blanket that is rated to some extremely high temp? I do know that from the e-bay seller, that sells kaowool and the non-ceramic blankets, that the non ceramic is about half the cost? Could someone comment on the non ceramic. ("gee, Tom, you shouldn't have used that non-ceramic blanket, that's why your oven burned down" - hate to hear that later)

3. how about the insulfrax or kaowool alone, just extra layers.- So, we know what a roll costs,what I don't know is how many rolls do I order to get three layers- 3 rolls? is 3 layers enough? assuming I am not going to use vermiculite. This also means that I will use super isol under the oven, not a layer of vermiculite and cement.

4. why do you have to cover the insulfrax with the anything at all? Specifically, that mud layer.

thanks

Tom

[Kemo]

Tom,

I would like to know too...I dont like spending more money than I have to.

[maver]

1. insulfrax from FB store is safer than kaowool but the performance is likely to be similar. Members of this forum have used both insulfrax and 'non-safe' ceramic blanket insulation like kaowool

2. Non-ceramic fiber blanket rated to really high temps? I looked up superwool 607 and it appears to have identical thermal conductivity to kaowool so that should also be ok.

3. Generally 1 roll is 50 sq ft and covers the dome once. If you use insulfrax or kaowool or superwool you'll want 3 inches or you can replace any layer with 2 inches of perlite/vemiculite.

4. You don't have to cover the insulfrax with anything if it is an interior oven that is surrounded by other building materials, but the insulfrax will not perform well if wet so for exterior ovens you need an enclosure.

Marc

[asudavew]

1. If forno bravo sells isofrax ceramic blanket, someone must think its better than kaowool ceramic blanket. Is there much cost differential between the two? Is there much performance differential?


Isofrax 1260°C Blanket is applied as high temperature insulation in the metal, petrochemical / power, ceramic & glass production industries. Isofrax has a temperature rating for use up to 1260°C (2300°F), but the blanket can withstand short-term excursions to higher temperatures - with moderate shrinkage.

Kaowool Blanket 8 LB 2300oF maximum temperature rating.


Isofrax - 50 sq feet, 1" thick - $150.00
Kaowool - 100 sq feet, 1/2" thick - $289.00

2.How about the non-ceramic fiber blanket that is rated to some extremely high temp? I do know that from the e-bay seller, that sells kaowool and the non-ceramic blankets, that the non ceramic is about half the cost? Could someone comment on the non ceramic. ("gee, Tom, you shouldn't have used that non-ceramic blanket, that's why your oven burned down" - hate to hear that later)

Superwool 607 Blanket - 4 LB Density - 1 Roll/Carton (50 SF) Size 300" x 24" x 1" 2012oF maximum temperature rating.

3. how about the insulfrax or kaowool alone, just extra layers.- So, we know what a roll costs,what I don't know is how many rolls do I order to get three layers- 3 rolls? is 3 layers enough? assuming I am not going to use vermiculite. This also means that I will use super isol under the oven, not a layer of vermiculite and cement.

Not sure about the number of rolls.

4. why do you have to cover the insulfrax with the anything at all? Specifically, that mud layer.

If you put enough on, then I suppose you wouldn't need vermiculite or "mud". But it does need protection from the environment. I assume you read James study of vermiculite vs ceramic blankets.

[CanuckJim]

Part of the reason for coating the outside of the blankets is to eliminate the problems created by possible open seams. This is the cheapest part of the equation. Why not do it? It's an extra measure of peace of mind, it's quick, cheap and easy to do, barring space problems. Remember, you cannot have too much insulation.

Jim

[wlively]

Tom

There is no one best brand for blankets. Here are two sources that give details on blankets, manufacturers, specs, uses, composition.

http://www.thermalceramics.com/upload/pdf/514-205.pdf

Spiral Arts

When comparing blankets, the number to look at is thermal conductivity. The lower the number the better the insulator. At the temps we are using, most brands will be very close in range, which lets you fall back on cost as the denominator. You want the 8lb weight, the higher the weight the higher the fiber density.

The "safe" blankets are made with a water soluable fiber that is not as harmful to inhale. The std balnkets require a mask as you do not want the fibers in your lungs.

I thought best to use two blankets a 2" and then a 1" over that. The main reason for two is I wanted complete overlap coverage of all the 1st blanket seems. Whatever you put over that pretty much depends on your finished structure shape; dome or house. I went with house, so I filled the enclosure with Harborlite (fine silicon coated perlite). It is cheap $10 for 4 cu ft bag and pours like water, so it fills everything.

Being on a strict budget I had to find the cheapest for everything. The best source for blankets I found was here;eBay Store - HIGH-TEMP REFRACTORY STORE: Ceramic Fiber Products, Mortars and Coatings, Insulating Firebrick Very helpful and if you don't see what you want on the website call them, they will have it.

The others have repeated the old axium, never too much insulation. That is true.

[james]

I can add to this.

On the vermiculite vs. woven ceramic insulation question, I think that at least one blanket is worth the little bit of extra cost over a straight vermiculite installation. The modern cermatic blankets do such a good job of stopping heat migration and keeping the cooking chamber hot.

The 1" blanket and 4" of vermiculite schedule is a mainstream approach, and experience (and the thermal spreadsheet) show that it is effective at holding in heat, and keeping it from reach the outer edge of your enclosure.

Still, if you are looking to do a great job of insulating your oven, or are looking for a clean and quick installation method, going to 3" of ceramic blanket is a good strategy. It goes in fast and works great. You can overlap the seams and it will be efficient. As some areas report difficulty find vermiculite -- it is also a very easy way to shop. The only downside is cost.

FB chose Insulfrax because it is water soluable -- which means that it will not stay in your chest should you breath it in. Wear a mask regardless.

We chose SuperIsol (Cal Sil) because we thought it would stand up to the heat and weight of an oven. Thermally, it stops the heat of the oven with 2", though if you are going for a great insulation job, you can double that with only a little more cost.

FB wants to be the best source of installation accessories, and we are working on making our selection better. More to come on that.
James

[jwnorris]

Originally Posted by james

<snip> Thermally, it stops the heat of the oven with 2" ... <snip>

I had posted this to another thread but, I think that it bears repeating. My oven is a FB Casa110 setting on a 2 inch layer of SuperIsol board supported by a 1/2 inch layer of cement board on a metal stand.

The other day, after firing the oven to a smokin" 900 F in the dome, the underside of the cement board measured 140 F. I had gotten side tracked along the way and had not moved the fire to the rear corner of the oven as early as I normally do so the floor was a bit below the 900F mark itself in the center.

While more insulation may drop that some; depending on the method of insulation, it may not add enough value. I am very pleased with the level of insulation.

J W