Pebble-filled mass - pebbles settling over time.

Folks using a pebble-filled box for their mass -

Do you experience settling of the pebbles?  

I have a pebble mass, and when the fire gets going, there is a periodic settling of pebbles on the inside.  It sounds kind of like winning a slot machine - an interior cascade of rocky tink-tink-tink.  And over time, the overall level of the pebbles drops.  I don't know if some pebbles are cracking due to the heat, or what.  Not a big deal, I just top it up once or twice per winter.  Just curious if other folks have experience this and if anyone has any advice to mitigate or shed some light on the cause.

To add context, this is not a RMH, but a cast iron pot-belly wood stove, with a brick and tile box filled with pebbles surrounding it.  The box serves a few purposes: protective perimeter for some rambunctious, cooped-up kiddos, heat shield, mitigation of too much immediate heat, and slow dispersal of accumulated heat.  

Beau Davidson wrote:
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To add context, this is not a RMH, but a cast iron pot-belly wood stove, with a brick and tile box filled with pebbles surrounding it.  The box serves a few purposes: protective perimeter for some rambunctious, cooped-up kiddos, heat shield, mitigation of too much immediate heat, and slow dispersal of accumulated heat.  

Sorry I can't answer your question, because my pebble style RMH is still in the planning stage. But I was intrigued by the mass you built around your wood stove. I'd love to see more pictures of it. I just put a small stove of a similar style into our daughter's tiny house and need a good solution to the issues you mentioned.

Thanks,
Tim

I’ve been considering doing a gabion basket around our stove to gain mass since I have very poor masonry skills.

This was my idea as well for the small woodburning stove I had planned on putting in the earthbag greenhouse that I never built. My thought was to build a cob cove for it and slide it in there. The greenhouse was never built due to a long drawn out reason.  Otherwise, the WBS is still in the garage being used as a shelf.

I'm new here and learning a lot, But doesn't enclosing the stove make the metal too hot and might crack it? Even cast iron can only take so much heat right?  Just wondering. thanks

a bennett wrote:I'm new here and learning a lot, But doesn't enclosing the stove make the metal too hot and might crack it? Even cast iron can only take so much heat right?  Just wondering. thanks

Maybe good to consider - but my thinking is that pebbles still allow air circulation.  You can definitely not get this anywhere near as hot as you would an RMH!  And, like with any metal stove, I have to be careful with high btu wood.  It is a stop-gap solution, for sure, until I can get an rmh built, but we travel a lot in winter so our window of usage is relatively short.  After I upgrade to an rmh, this will probably go in the garage/shop to get used a couple times a year.

Side-note: this stove was a gift from my friend Eric VonRaderson to help keep my family warm when we first landed at our weird little microhome a few years ago.  It has been a treat, and has done the trick, and I think you again, Eric!

Tim Osborn wrote:I'd love to see more pictures of it.

I'll take some more pictures for you.  Though I would definitely recommend taking a couple weekends and building a pebble-style RMH (like this one from Free Heat instead.

 a bennett wrote:
But doesn't enclosing the stove make the metal too hot and might crack it?

This is definitely a valid concern. Woodstoves are designed to radiate heat, and if that doesn't occur adequately, they can warp (steel) or crack (cast iron). So you need good air movement to allow that radiation to happen. You are creating tremendous heat in an area of a few cubic feet, to then heat an area of hundreds or thousands of cubic feet. To get that vastly bigger area heated requires much air movement. The RMH, in addition to having a non-metal firebox and combustion chamber, spreads that heat into a many-cubic-foot bench or other mass which absorbs the heat and then releases it. What's shown here 'could' be problematic if run at too high a pace for too long. It's a good idea, as the mass absorbs heat and offers a barrier, but bricks or pebbles can't absorb heat as quickly as moving air. You might want more air space between the stove and the bricks, or maybe a fan forcing airflow to happen, if it was running hot enough to heat a good sized area for days at a time.

What are you calling the unit you describe as " their mass".