New hearthstone line. Green mountain cat

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jetsam

Minister of Fire
Dec 12, 2015
5,337
Long Island, NY
youtu.be
Heating a thermal mass is a traditional way of storing heat, and it works.

Don't confuse that with the large efficiency loss you see from insulating a steel stove with stone, which is far less thermally conductive. All that heat that could have been conducted into your house is going up the flue because stone is a relatively poor thermal conductor.

Thermal capacity and thermal conductivity are not the same thing.
 
Jan 12, 2016
31
Newland, NC
That’s pretty risky messing with a gas unit that way.
Did you actually put it inside of a direct vent unit?

Soapstone does have great heat retention values, it’s an incredible insulator. That’s why I don’t want it in my wood stove, I want the stove to release heat into the room, not store it inside the stove, in turn sending it up the flue..

This fireplace unit is designed with 2 trays that holds fireglass (which also has heat retention properties - just not as good). The unit is designed to heat the firebox and the blower pulls from the bottom and up over the firebox in order to provide heat to the room. The longer you can keep the firebox at temp the more efficient the unit is. I cut two slabs of soapstone to go where the fireglass should be. Picture is blurry - sorry.

15073398_10210952423751183_220781535590279621_n.jpg

Testing unit pic - closed up:

21768343_10213948901581256_4614988230827688758_n.jpg
 
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Jan 12, 2016
31
Newland, NC
Heating a thermal mass is a traditional way of storing heat, and it works.

Don't confuse that with the large efficiency loss you see from insulating a steel stove with stone, which is far less thermally conductive. All that heat that could have been conducted into your house is going up the flue because stone is a relatively poor thermal conductor.

Thermal capacity and thermal conductivity are not the same thing.

Soapstone is one of the best of both worlds it both retains heat and radiates it well as it is a very good thermal conductor. Many places sell soapstone chips in lieu of fireglass and lava rocks. I have a modern look gas fireplace (no firelogs). Soapstone has the ability to absorb, hold and radiate heat better than many other options. Just putting soapstone in any old gas logs - no, that is not what is occurring. This product is designed for a secondary product (fire glass, lava rocks, etc.) to be a part of the heat process.


The reason soapstone is used in for woodstoves - cookstoves - etc. is it's excellent heat absorption, retaining and radiating abilities. This is not granite. NOTE: Soapstone chips were available as an option for my insert, I chose to cut custom slabs instead.

The heat is not going - up the flue at a greater rate without the flame, it is radiating heat into the room real world measure and scientifically. The heat is lasting longer before refires of the gas. Using less gas is my real world measure.

I did not just throw stone in a fireplace designed for other purposes. Nor is it insulating the stove as you can see from my pics. It actually radiates heat to the stove after the fire has cut off.

I think the confusion comes from saying I "lined" the gas fireplace with soapstone. I knew what I meant, but it would certainly look like I meant coated all the inside. I put soapstone in the appropriate place designed for an element that could retain and radiate heat.
 
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jetsam

Minister of Fire
Dec 12, 2015
5,337
Long Island, NY
youtu.be
Soapstone is one of the best of both worlds it both retains heat and radiates it well as it is a very good thermal conductor.


Carbon steel is around 50 W/mK at 0.5% carbon. Tulikivi says soapstone is about 6.4 W/mK- so it conducts about 13% of the heat that plain steel does. The real world figure is a lot worse, since realistically the soapstone is going to be a lot thicker than the steel.

Anyone who says it's "good" may be comparing it to fiberglass insulation.

Ask anyone who has soapstone.... it's nice, soft heat. Unfortunately, that is the opposite of efficient heat.
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
How did the soapstone effect the flue gas temperature?
 
Jan 12, 2016
31
Newland, NC
Carbon steel is around 50 W/mK at 0.5% carbon. Tulikivi says soapstone is about 6.4 W/mK- so it conducts about 13% of the heat that plain steel does. The real world figure is a lot worse, since realistically the soapstone is going to be a lot thicker than the steel.

Anyone who says it's "good" may be comparing it to fiberglass insulation.

Ask anyone who has soapstone.... it's nice, soft heat. Unfortunately, that is the opposite of efficient heat.


I hope that you looked at my picture. The efficiency in real world for me is measured by how long my heater can keep my area at the designated temperature using the least amount of gas.

Sure, if I had lined the whole stove with soapstone, effectively insulating the steel from the heat source I would lose more heat through the venting.

That is not what is happening. I am using soapstone as the stove intends (to use some sort of thermal mass) just modifying it somewhat to make for a greater thermal mass and hence greater retention and a longer release of that slow heat. The longer I can radiate your "soft heat" into the room and hence to the thermostat the less gas I use.

Instead of using chips of something I opted for a solid mass cut to fit. Gaining more than double the thermal mass of the bag of chips that was an option. The thin steel (nothing like a real wood stove steel) of a gas stove radiates great, but it does not really do much on retention. I more than make up for in thermal mass with the soapstone the relatively small area I may insulate. I will take that soft heat and my use of less gas any day than my last year of on off gas all the time.
 

begreen

Mooderator
Staff member
Nov 18, 2005
96,279
South Puget Sound, WA
Soapstone does have great heat retention values, it’s an incredible insulator. That’s why I don’t want it in my wood stove, I want the stove to release heat into the room, not store it inside the stove, in turn sending it up the flue..
Just in case someone is thinking of building a hearth out of soapstone - it's a very poor insulator. somewhere around R 0.02/inch. It's dense structure gives it fairly good thermal conductivity for stone. Firebrick, especially pumice firebrick is a better insulator and that is a good thing for keeping the firebed hot.
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
Just in case someone is thinking of building a hearth out of soapstone - it's a very poor insulator. somewhere around R 0.02/inch. It's dense structure gives it fairly good thermal conductivity for stone. Firebrick, especially pumice firebrick is a better insulator and that is a good thing for keeping the firebed hot.
So what value is it in a firebox?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,130
central pa
So what value is it in a firebox?
Heat retention. It is not there to act as an insulator it is there to retain heat and release it later.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,130
central pa
It’s a cast iron stove with no ashpan. It also is designed with an inherent flaw. The 2 steel cats are positioned vertically directly below the flue collar. These will constantly be plugging with ash! Not a good move..
Is this like the flaw you pointed out with the regency hybrids that has proven not to be a problem?
 

Rearscreen

Minister of Fire
Dec 21, 2014
785
Vermont
Interesting discussion. Heat goes to cold in direction. Log burns and heat goes to steel that is colder because it is transferring that heat into the room. Log burns faster. Stove colder in morning. What am I missing in my Fred Flintstone brain?
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
Is this like the flaw you pointed out with the regency hybrids that has proven not to be a problem?
You are correct, they didn’t really experience problems with cat failures once they changed the only thing that they didn’t copy from Blaze King. Now that it’s an exact copy things seem fine. If you look these over, there only 1 difference now, burn times. Their burn times are grossly exaggerated! The cats aren’t failing now at least.
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
Heat retention. It is not there to act as an insulator it is there to retain heat and release it later.
As we all know, a few pounds of stone, inside a cast iron box will throw tons of heat into the room... please
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,130
central pa
As we all know, a few pounds of stone, inside a cast iron box will throw tons of heat into the room... please
We all get it you dont like hybrids or soapstone. That doesnt mean those things are bad
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
We all get it you dont like hybrids or soapstone. That doesnt mean those things are bad
I’ve had both, not many people have. They aren’t all bad, I’m just not sold on either of them.
 

begreen

Mooderator
Staff member
Nov 18, 2005
96,279
South Puget Sound, WA
So what value is it in a firebox?
I was speaking to the statement that soapstone a good insulator, which it isn't. I don't have a strong opinion on its value in a firebox, never having burned a stove with it. Give Lorin a call at Woodstock for an opinion. Looking forward to when you get a chance to try an IS stove.
 
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webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
I was speaking to the statement that soapstone a good insulator, which it isn't. I don't have a strong opinion on its value in a firebox, never having burned a firebox with it. Give Lorin a call at Woodstock for an opinion. Looking forward to when you get a chance to try an IS stove.
I’d love to try one out!
 
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Highbeam

Minister of Fire
Dec 28, 2006
19,996
Mt. Rainier Foothills, WA
I’d love to try one out!

Me too. They’re on sale you know?

I’ve had a fully stone stove and nothing about the soapstone made me wish any of my future stoves used it. I don’t miss the soapstone at all. It looks nice but was actually a negative for me due to slow warm ups, less efficiency, and potential for cracks. Fortunately, even hearthstone and Woodstock are moving to welded steel with their new models.
 
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webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
Me too. They’re on sale you know?

I’ve had a fully stone stove and nothing about the soapstone made me wish any of my future stoves used it. I don’t miss the soapstone at all. It looks nice but was actually a negative for me due to slow warm ups, less efficiency, and potential for cracks. Fortunately, even hearthstone and Woodstock are moving to welded steel with their new models.
Same issues here.
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
Me too. They’re on sale you know?

I’ve had a fully stone stove and nothing about the soapstone made me wish any of my future stoves used it. I don’t miss the soapstone at all. It looks nice but was actually a negative for me due to slow warm ups, less efficiency, and potential for cracks. Fortunately, even hearthstone and Woodstock are moving to welded steel with their new models.
Hopefully people that have never had one don’t come along and beat you up too bad for speaking out against it...
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,130
central pa
Hopefully people that have never had one don’t come along and beat you up too bad for speaking out against it...
Who hasnt owned one? I have yet to own a hybrid but i have owned a hearthstone.
 
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jetsam

Minister of Fire
Dec 12, 2015
5,337
Long Island, NY
youtu.be
Interesting discussion. Heat goes to cold in direction. Log burns and heat goes to steel that is colder because it is transferring that heat into the room. Log burns faster. Stove colder in morning. What am I missing in my Fred Flintstone brain?

"Heat" and "cold" aren't two physical entities that have a magnetic attraction to each other- they're different spots on a spectrum of how much energy one given chunk of matter has at a given instant. ( If you want to get really technical, nothing "has" heat, it has energy; heat happens when energy is transferred. )

Burning a stove in a 0°F room doesn't make the log burn faster than if the room was 100°F (in fact it works the opposite way briefly- before the flue warms up a little, you'll have poor draft if inside and outside are the same temperature).
 

Rearscreen

Minister of Fire
Dec 21, 2014
785
Vermont
the 2nd law applies to the spontaneous flow of heat from hot to cold. Dan Holohan the radiant heating guru guy explains it this way. Heat from your body (or anything) moves from you to a colder surface including oddly cold radiant. In a grocery store down the freezer isle you will feel cold as the cold freezers are sucking (energy) from your mass. The air is the same temp as the canned food isle. That's why radiant floor heat is so efficient. Any surface above your body temp is comfortable. With this logic, the radiant from the log will hit the steel which is cooler as it's radiating (dissipating energy) into a cooler room and objects. A slightly more "insulator" soapstone would resist this sucking of energy to a colder surface. They say a BTU is a BTU, but I question that as radiant heat seems to have different properties than the properties of faster moving air molecules. Again, an interesting discussion.
 

Rich L

Minister of Fire
Jan 25, 2008
846
Eastern,Ma.
g-mail.com
This fireplace unit is designed with 2 trays that holds fireglass (which also has heat retention properties - just not as good). The unit is designed to heat the firebox and the blower pulls from the bottom and up over the firebox in order to provide heat to the room. The longer you can keep the firebox at temp the more efficient the unit is. I cut two slabs of soapstone to go where the fireglass should be. Picture is blurry - sorry.

View attachment 224881

Testing unit pic - closed up:

View attachment 224882

Hey partner you must be new around here.You say soapstone you could get yourself hung.
 

webby3650

Master of Fire
Sep 2, 2008
11,133
Indiana
Hey partner you must be new around here.You say soapstone you could get yourself hung.
In this instance only because altering a gas fireplace could be deadly.