Grandma Bear Underneath Hearth Gets Hot

[Frankdozer]

Using my Grandma Bear this past winter, the hearth directly under the stove got too hot to hold your hand on. So I placed a layer of bricks on the hearth to lessen the heat there. I’m thinking of fabricating a baffle to lessen the heat transfer. Are there any pictures of the underneath baffle and how it’s hung from the stove that someone could post.

 

[coaly]

I simply put a small C-clamp on each leg about 1 1/2 inch below stove bottom and set a sheet metal shield on them. No drilling or modifying stove. Huge difference, stays cool under stove.



This was my kitchen stove where the original Goldilocks on pedestal was. I wanted a larger cooktop, so used this brown Mama Bear for a couple years until getting the kitchen Queen. The plywood subfloor is overlaid with 1/2 cement board, then tile. The R value is not enough, it must be double rock board, then preferably brick. It got uncomfortable to the touch directly under the center, so I raised it on bricks to gain clearance, still too hot. I had a bunch of fireplace damper clamps used for holding a damper closed when installing gas log sets. Had an old metal shelf just the right size to fit between the legs and sat it on the clamps. Stayed cold under stove!

 

[coaly]

The factory shield is open across the front as an intake under the ash fender like the intake of an Insert, and goes up the back, so air moves across the bottom and rises up the back. It is pictured in the later manuals.

 

[Frankdozer]

Thanks for the info Coaly. I think I’ll make a plate to fit between the legs supported with clamps as you mentioned. But I’ll have the plate extend beyond the back of the stove about 1” and turn 90 degrees up about 2” so as to direct the heat up by convection. I think 18 gauge black iron would work fine painted to match the stove.
I’m thinking to clamp the plate 1” down from the underside of the stove.

 

[clancey]

i came across this thread and I think that stove setting and stove is just "neat"--old timey and wonderful...especially with the kettle on that beautiful brown fisher stove...clancey

 

[John Bramhall]

Early Fisher's were not shielded so they created the need for greater clearances. (36" to combustibles). As a dealer I have seen a couple of instances where an improper hearth actually burned through. Installing a metal shield is the best way to prevent the overheating. Several times I have had to shield the back and side walls with a noncombustible material using noncombustible spacers.

 

[Frankdozer]

Early Fisher's were not shielded so they created the need for greater clearances. (36" to combustibles). As a dealer I have seen a couple of instances where an improper hearth actually burned through. Installing a metal shield is the best way to prevent the overheating. Several times I have had to shield the back and side walls with a noncombustible material using noncombustible spacers.

I set a second layer of brick under the stove. Top brick temperature is 142 degrees. Underneath that brick top is 120 degrees.

 

[John Bramhall]

That is probably sufficient. You could always install a metal shield to make yourself feel better. Not that it is a consideration here, but combustibles that have been exposed to heat for an extended period of time have been known to ignite at temps as low as 200 degrees F. This is know as pyrolysis and it only occurs after long periods of time when exposed to high temperatures.

 

[checkthisout]

That is probably sufficient. You could always install a metal shield to make yourself feel better. Not that it is a consideration here, but combustibles that have been exposed to heat for an extended period of time have been known to ignite at temps as low as 200 degrees F. This is know as pyrolysis and it only occurs after long periods of time when exposed to high temperatures.

I have heard of this but don't understand how that can happen. Does the heat slow-cook the wood or whatever into something that will ignite at 200 degrees?

 

[stoveliker]

I have heard of this but don't understand how that can happen. Does the heat slow-cook the wood or whatever into something that will ignite at 200 degrees?

Yes. In essence it becomes a bit punky - tho thru a different mechanism; not fungal. And dry.