6 Lb v. 8 Lb Ceramic Blanket

[Gromit]

Harbison-Walker has 6 Lb per CUFT Inswool 1" ceramic blanket for $0.50 sqft; their 8 Lb per cu ft 1" blanket is $1.50 sqft. The FB blanket is 8 LB cu ft, but is on backorder.

For the same money, I could put a lot more of the the 6 Lb blanket on. Is there any drawback to that approach? The 6 Lb. blanket feels very compressible; I have not compared it to the 8 Lb.

Thank you to anyone who has answers.

[Wiley]

Re: 6 Lb v. 8 Lb Ceramic Blanket

David, Here's a link to a web site which has some graphs and data regarding thermal transmission per inch thickness of ceramic insulating blanket. From reading at the site and looking at the graphs it would appear that if you have the space multiple layers of the 6lb would insulate better than single layers of the 8 lb. Since your price comparison indicates that the cost of multiple layers would be the same (in the case of three layers versus one), I think that if you have the space it is worth consideration.
Here's the link, read and make your own decision:

http://prug.espacios.net.mx/fibratecnew/pdf/NFprint.pdf

Bests,
Wiley

[Gromit]

Re: 6 Lb v. 8 Lb Ceramic Blanket

Wiley,

Thanks for the link. I am actually tight for space with only 2.5" between brick and cement board enclosure at the 12 o'clock, 3 o'clock and 9 o'clock points on the dome. I am pretty sure I could squeeze five or six layers of the 6 Lb. blanket into that 2.5", but I am not sure whether I am being counter-productive at that point.

[Dino_Pizza]

Re: 6 Lb v. 8 Lb Ceramic Blanket

David,
My opinion is that compressing your insulation at those 3 points (2.5") is fine and the multiple layers of 6lb blanket would be fine as long as you can get the equivalent of 2-3 layers of FB blanket out of it. And definitely go for more on the upper part of the dome since you've got room for it. It's so cool to feel your dome top at ambient temp when the oven is 800 deg a few inches below your hand.

[KraemerBAC]

Re: 6 Lb v. 8 Lb Ceramic Blanket

Hey David,

What a deal on the 1 inch 6# blanket at $.50/sqft...my local, Chicago, dealer quoted me at $2.42/sqf. it is making me wish I was also in Houston.

Peter

[Gromit]

Re: 6 Lb v. 8 Lb Ceramic Blanket

Either I got quoted wrong prices over the phone or I was doing some funny math in my head. I just got back from picking up a box of 8 LB for $1.44 sqft. The 6 LB was $1.07 sqft. They had another 6 LB inswool rated to 1,800 deg instead of 2,300 deg for $0.97 sqft.

[KraemerBAC]

Re: 6 Lb v. 8 Lb Ceramic Blanket

David,

Still a great price compared to what I got quoted..I don't suppose you have a stock number on your receipt...Just checked out your build thread..Love the oven!!! How much blanket did you end up buying??

Where in Houston are you?? My wife is from Houston and I have family in Galveston

Peter

[Gromit]

Re: 6 Lb v. 8 Lb Ceramic Blanket

Item #69998 1x24x25 HP BLANKET 8#

Perhaps they were quoting you a 2" thick blanket or maybe one rated for higher temperatures. 'HP' is their 2300 deg blanket; they have a lot of variations.

[KraemerBAC]

Re: 6 Lb v. 8 Lb Ceramic Blanket

Thanks David,

I'll check with that item #

Peter