Hearth Pad R-Value for Crane Model 44

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skobydog
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Post by skobydog » Tue. Sep. 24, 2013 2:24 pm

The instructions say "standard 1/4 in thick asbestos millboard covered by 28 gauge steel or its equivalent". I'm building a hearth for my wood stove but want to make sure the R-value is high enough for the Crane stove.

The R-value for the wood stove is a bit low I think because it's a pedestal stove. It's 1.0 or greater but I was going to beef it up anyway. Anyone know what the Crane stove should be? The instructions call for 1/4 in asbestos millboard covered by 28 gauge steel but I don't know what the R-value equivalent would be. Thanks for any help on this.

 
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michaelanthony
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Post by michaelanthony » Tue. Sep. 24, 2013 3:00 pm

What model Crane stove are you concerned with and does it have a heat shield? A hearth pad can be made many many ways based on the look you want and the size you need. I built one with 3/4" sub flooring and 12 x 12 ceramic tile over that. Insulation is the trapping of air and "R" value is the time it takes to transfer heat in a given area, so air space slows the tranfer of heat and the "R" value is dependent on the material used.
Did not know you could still purchase asbestos. :?
Sorry, I just put my glasses on and saw the stove model :lol: d.c. should be along soon :oops:

 
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dcrane
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Post by dcrane » Tue. Sep. 24, 2013 3:13 pm

R = 1.4 (but things have changed drastically since then), I suggest if your building a hearth you consult with the local building inspector before having him come over to sign off on it (saves a lot of aggravation down the road... he will tell you what he likes to see), the clearances can then be given to him from the manual you have in hand (or they can found in the coal burners almanac here Copy of Manual for Crane 44)

Off the record... the Crane 44 is about the safest coal stove I've ever seen, I have run them full bore to the point I could almost see through the side wall while they sat on factory fir flooring toothy (I don't recommend you do this but just saying).

also Michael is correct... you cant buy asbestos millboard anymore (and you would not want to anyways). You can buy safer non-asbestos products now... but the answer to your main question is 1.4 was the R value in that example.


 
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skobydog
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Post by skobydog » Tue. Sep. 24, 2013 5:23 pm

I am using Durock Next Gen 5/8" sheets have an R-Value of 0.49 and the 1/2" sheets have an R-Value of 0.39.

My wood stove calls for only 1.0 but I'd be over than not enough.

(3) x 1/2" boards = R-Value of 1.17
(3) x 5/8" boards = R-Value of 1.47

1/2 = $9.98
5/8 = $12.66

I'd rather make the Hearth pad correctly the first time for a few more dollars than to come up short on R-value and have to redo it.

 
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skobydog
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Post by skobydog » Tue. Sep. 24, 2013 7:23 pm

dcrane wrote:R = 1.4 (but things have changed drastically since then), I suggest if your building a hearth you consult with the local building inspector before having him come over to sign off on it (saves a lot of aggravation down the road... he will tell you what he likes to see), the clearances can then be given to him from the manual you have in hand (or they can found in the coal burners almanac here Copy of Manual for Crane 44)

Off the record... the Crane 44 is about the safest coal stove I've ever seen, I have run them full bore to the point I could almost see through the side wall while they sat on factory fir flooring toothy (I don't recommend you do this but just saying).

also Michael is correct... you cant buy asbestos millboard anymore (and you would not want to anyways). You can buy safer non-asbestos products now... but the answer to your main question is 1.4 was the R value in that example.
BTW, thank you for the info :)

 
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dcrane
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Post by dcrane » Tue. Sep. 24, 2013 8:28 pm

no problem at all... welcome to the forum and please post up some pics in a thread when the stove is up and running :up:

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