Soapstone questions

[Builder Bob]

I am considering a Hearthstone Mansfield for a new house, and had a couple of questions about it.
1. I am wondering about the amount of time it takes for the unit to go from room temp to producing heat?
2. Since it is constructed with stone panels, how often do you have to "rebuild" or seal the corners etc.?

Any help or pointers would be appreciated.

Bob

 

[Highbeam]

I had some of the same questions before I bought my Heritage and inquired with Tom of the Chimneysweeponline site. He is also a member here and I hope it is OK if I repeat it.

Most of his prompt and courteous reply:


"The soapstone panels on Hearthstone woodstoves are over 1-1/4" thick, and go all the way through: in other words, you see the outside of the stones from outside the stove, and the inside of the same stones from inside the stove. Ever do any wood joinery where, for added strength, you used "bisquits"? All four edges of each stone panel in a Hearthstone stoves have deep grooves cut into them. When the stones are put together, a thick plate steel "bisquit" is inserted in the corresponding grooves of each pair of stones to be joined. The entire stone assembly is then held together by an outer cast-iron frame, which is bolted together. The stones can't leak or come apart, and the stoves never have to be torn down and rebuilt."



Now when I got the stove I can see what looks like a woven gasket wrapping the bisquits that are inserted between the panels. Only in a couple of places since the panels are joined as well as cemented.

Heat is made almost immediately through the window but I expect that an hour will pass before a stone cold stove will see surface temps of 300. That's what my research tells me but the surrface temps won't be setting at 600 like on a steel stove. It should get up to 500 and that's about it.

Mine is still on the pallet while I build the walls and hearth. I removed a masonry fireplace and chimney to make way for the hearthstone.

 

[Todd]

1. I can get my stove up from a cold start to 500 in 45 min using smaller splits. Then you have a good coal bed established for your bigger long burn splits.
2. As long as you don't over fire the stove it should last decades before having to rebuild.

 

[Builder Bob]

Highbeam,
The cemented joints were the ones I was questioning. I was curious about them and how tight the joints would be in future years of burning, and potential air leaks and possible over firing thru them.
I have experience with steel stoves, (presently have an Avalon Ranier) and would like to not get run out of the room when the stove is burning strong.

Bob

 

[Hokerer]

We've got 8 full seasons in on our Hearthstone Phoenix and nary a single sign of anything needing any "rebuilding"

 

[Highbeam]

When I said that the joints are both joined and cemented I meant that they were joined and cemented with the cement just being a backup to the biscuited joint.

I have a problem with a stove that needs to be rebuilt due to leaks during their service life. Most if not all of the nice cast iron stoves need to be checked regularly and that isn't cool. If this soapstone needed to be checked for leaks and rebuilt then I would have bought a welded steel stove. Current owners and Tom assured me that this stove isn't going to fold up like a deck of cards.

The service tech that came out to fix a manufacturing defect had some stories about these stoves such as the one guy who overfired the heck out of his and actually melted the cast iron framework that supports the roof. It still ran but the top was all warped and needed to be replaced. The other common problem that the tech pointed out was the crumby door latch system breaking. Hearthstone has since redesigned the door latch to include a replacable contact surface in the door frame. Otherwise the soapstones have been very good said he.

Supposedly the stoves heat in such a way that you can sit right next to it while it is pumping out the heat. Certainly a stove at 400-500 is much less abrasive than one at 650. My big Lopi stove could be to 600 within 45 minutes too so there is no apparent penalty to the soapstone once you learn how to run it.

 

[bmstove.com]

NO PENALT AT ALL. Soapstone = Advantage.

Lets say you do spend an extra 30 minutes getting the mansfield up to full temp as compared to a steel stove. Look at the other end of the burn; saturday morning, 9:30 am and you are not even thinking about getting up. the mansfield's fire may have gone out at 8 but you are gonna be getting heat until noon or better! I'll take that trade-off any day. That steel stove is gonna be cold almost as soon as the fire dies out.

This is no lie and since you're not buying your mansfield from me you can believe it or not. Hearthstone rates the mansfield at a 10 hour burn time. I think that is for the first time stove owner. I load mine full at the store (seasoned on bottom and some not so seasoned on top) and walk out the door at 5pm. When I walk in at 9am the next day I open the air, stir up the chunks and watch them blaze up! 16 HOURS BABY and the stove is still HOT! and that's no joke. It's a good one. I can't wait until my equinox gets here so I can see what it will do to.

Jack

 

[BrotherBart]

NO PENALT AT ALL. Soapstone = Advantage.

Lets say you do spend an extra 30 minutes getting the mansfield up to full temp as compared to a steel stove. Look at the other end of the burn; saturday morning, 9:30 am and you are not even thinking about getting up. the mansfield's fire may have gone out at 8 but you are gonna be getting heat until noon or better! I'll take that trade-off any day. That steel stove is gonna be cold almost as soon as the fire dies out.

This is no lie and since you're not buying your mansfield from me you can believe it or not. Hearthstone rates the mansfield at a 10 hour burn time. I think that is for the first time stove owner. I load mine full at the store (seasoned on bottom and some not so seasoned on top) and walk out the door at 5pm. When I walk in at 9am the next day I open the air, stir up the chunks and watch them blaze up! 16 HOURS BABY and the stove is still HOT! and that's no joke. It's a good one. I can't wait until my equinox gets here so I can see what it will do to.

Jack

Define "hot".

 

[Sandor]

I made the switch from steel to soapstone. The differences are well documented on this site.

Yes, the heat output on the soapstone is more gentle and even.

I only recommend soapstone stoves to people that run them for days at a time. Its not the right appliance for an occasional Friday night fire and the ensuing near instant warmth.

Starting a cold soapstone stove requires more small splits, because the thermal mass keeps pulling the heat from the firebox. On the flip-side, restarting the stove is way easier with just some burning embers.

 

[bmstove.com]

I mean untouchable and still radiating usable heat that can be felt. I have not come in and probed the stove and recorded its temperatures but it is still working was the point.

ah, good point on not recommending soapstone to casual users (although the look alone may be enough reason to go ahead). I do remember taking someone away from soapstone once. They had a solar home and as soon as the sun came up the house needed no heat. We agreed they may be trying to cool a soapstone stove down. Soapstone really helps out for folks that use them around the clock because they never cool off and stretch out the heat life. Pefect for working folks or people that don't stick around the house. Oh, and blind dogs and cats can always tell where in the house they are supposed to lay.

Jack

 

[Builder Bob]

The life of the fire is one of the main reasons I was looking at soapstone. Usually I would get home from work about 4:30, start the stove and burn thru the evening. Load it up for overnight, but by 2:30 or 3:00 the fan has cut off and the stove is cooling off. I would like to be able to stoke it in the morning and get it going, load it and come home in the afternoon and keep it going. Nothing would please me more than thumbing my nose at the gas company!

Bob

 

[Highbeam]

I am hoping for a two fire day where I start one in the morning and then it heats through the day and then when I get home from the day job I start another and stoke before bed. Ideally, the fire will be easy to restart and may even never go out but my smaller heritage isn't rated for those long burns. We'll see. My steel stove could be run that way but after the fire died the hosue would get cold pretty quickly.

No fans on the stove for me. Ceiling fan only.

 

[Sandor]

The life of the fire is one of the main reasons I was looking at soapstone. Usually I would get home from work about 4:30, start the stove and burn thru the evening. Load it up for overnight, but by 2:30 or 3:00 the fan has cut off and the stove is cooling off. I would like to be able to stoke it in the morning and get it going, load it and come home in the afternoon and keep it going. Nothing would please me more than thumbing my nose at the gas company!

Bob

Are you convinced yet?

 

[Builder Bob]

Thanks to everyone for the replies, good info.

Bob

 

[webbie]

Way back when, soapstone stoves were advertised as nirvana - the best thing ever to come up the pike! I have to say that I frowned upon some of the early advertisements, because they made claims that were a bit unreasonable (this is 1979 I am referring to!).....BUT, the consumer satisfaction that has been evident in the field in the last decade or so has convinced me that these stoves are the "right stuff" for certain customers. I think the pros and cons have been laid out pretty well above and in other threads, as well as in our article which compares stove materials.

One reminder is that thermal mass can be obtained in other ways besides soapstone. A heavy masonry wall (interior) and hearth can act as a heat sink, soaking up heat for hours and releasing it after the stove goes out. Also, heat retention and storage is somewhat related to mass (weight), so a 400 lbs soapstone stove is not going to do vastly more in storage than a 400 lb firebrick and steel one...yes, there is a difference in heat storage capacity, but it isn't a large amount.

The moderation of heat during the fire seems like one of the better features of soapstone.

As they say, there is nothing new under the sun. Russian and Finnish fireplaces, tile stoves and even antique soapstone stoves have been prized for centuries because of their moderation of the heat output.

 

[Todd]

Way back when, soapstone stoves were advertised as nirvana - the best thing ever to come up the pike! I have to say that I frowned upon some of the early advertisements, because they made claims that were a bit unreasonable (this is 1979 I am referring to!).....BUT, the consumer satisfaction that has been evident in the field in the last decade or so has convinced me that these stoves are the "right stuff" for certain customers. I think the pros and cons have been laid out pretty well above and in other threads, as well as in our article which compares stove materials.

One reminder is that thermal mass can be obtained in other ways besides soapstone. A heavy masonry wall (interior) and hearth can act as a heat sink, soaking up heat for hours and releasing it after the stove goes out. Also, heat retention and storage is somewhat related to mass (weight), so a 400 lbs soapstone stove is not going to do vastly more in storage than a 400 lb firebrick and steel one...yes, there is a difference in heat storage capacity, but it isn't a large amount.

The moderation of heat during the fire seems like one of the better features of soapstone.

As they say, there is nothing new under the sun. Russian and Finnish fireplaces, tile stoves and even antique soapstone stoves have been prized for centuries because of their moderation of the heat output.

Here is a quote from Woodstock.
Soapstone has twice the specific heat of either cast iron or steel. For example, the heat stored in 300 lbs of soapstone with an averagetemp of 450 is 25,000 BTU's. A 300 lb iron or steel stove would be able to store only half as much heat or 12,500 BTU's.
I think that is a pretty big difference.

 

[Rhone]

I have a soapstone insert, and normally it's about an hour for the fans to turn on, and they turn on at 180F. It's about 1 1/2 hours for me to start feeling "real" heat. Others seem to get their soapstone stoves warmed up in under an hour, I've done that only a few times in 2 seasons now. It used to take me a couple hours or more, there was a problem with my liner and after fixing it I'm very happy it only taking 1 1/2 hours now. But, it's important to note if I come home on a Friday at 6pm and the house is cold if I light a fire it'll be 7:30pm before I even start to feel the place warm up, by 9pm it will be warm. It's not as capable for the occasional use, stop and go type or quickly bring the house back up to temp in my opinion, it is more like a locomotive and more capable with a slow & steady sort of way of heating, and keeping smooth constant temperatures and best burned 24/7 which Sandor already mentioned. I went from steel to soapstone and probably won't go back, I really like the more constant output I guess, but it's also important to know that there is no winners or losers with soapstone. I don't think they're the nipple on the breast of life or anything, there are times I come home to a really cold house and wish it heated faster but more often than not for me my goal is to have even, more consistant heat and I burn it rather steady and for that purpose it works better than what I had expected so, that's why I probably won't go with steel again, the soapstone is more suited for my goals.

 

[webbie]

Here is a quote from Woodstock.
Soapstone has twice the specific heat of either cast iron or steel. For example, the heat stored in 300 lbs of soapstone with an averagetemp of 450 is 25,000 BTU's. A 300 lb iron or steel stove would be able to store only half as much heat or 12,500 BTU's.
I think that is a pretty big difference.

That sounds somewhat accurate - 12,500 BTU is the amount of heat a small stove running on it's lowest setting puts out in an hour. So it is not insignificant, but neither does it mean "hours and hours" of serious heat as the early ads mentioned.

So it gives out at the end what it saves up in the beginning.

My point is/was twofold - that a large masonry mass around a conventional stove can stove and release as much (or much more) heat than that, and secondly that the moderation of heat that soapstone provides on a constant basis may be the best single feature.....well, besides the style or the fact that they sometimes hold up for a century or two.