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CEB and fireplaces
  • Does anyone have any information regarding the application of the compressed earth bricks we can make using the GVCS in a masonry stove? I am thinking about their ability to store heat as a thermal mass, but more importantly, how they react to heat (i.e. will they run risk of explosion?).
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  • Unlikely to explode, though they might crack.  Cob ovens are made from clay and straw.  They are fired before being used.

    - Mark
  • Ovens/stoves/fireplaces are yet another application for ferrocement/metal lath.
  • @Jason, I know next to nothing about ferrocement/metal lathe, whereas I do know a bit about refractory bricks and stone.  Would you mind elucidating (or at least linking)?  
  • No problem. The goes "Nothing is New". CEB (I prefer Stabilsed Compressed Earth Blocks) can be used for Mass Heaters so why no chimneys (with Stain Steel Flue + Y20 steel bar inside corners from foundation to top plate (my chimney 8 metres high) ) and fire places (best long life with Fire Brick placed inside) . See Ianto Evans + Leslie Jackson book Rocket Mass Heaters at Cob Cottage Publications.
  • A masonry heater with fire brick liner and CEB outsides to store heat seems like it would be fine - they aren't exposed to hot flue gasses so they should be fine.  They're just fascia/mass at that point.  Its essentially a rocket stove at that point.  I'm thinking of buying a pdf copy of that rocket mass heaters book...

  • Won't the necessary temperatures to burn off all the gasses melt the metal?
  • What are you talking about, ARGHaynes?  What gasses?
  • Primarily creosote.  One of the virtues of a well build fireplace, I am thinking masonry stove, is that it burns off all of the vapors released, rather than just the usual low temperature ignitors.  Creosote buildup in the average fireplace is a result of a low and inefficient burn temperature.  Masonry stoves have two positive features.  First, their high thermal mass means that they absorb the heat and slowly give it off over time.  Second, they have a much higher temperature fire, which burns off more gasses (wood, similar to candle wax, does not burn, it gives off gasses that burn).  This reduces buildup of residue in the fireplace and increases the efficiency by using more of the energy stored in the wood.

    These temperatures are higher than those that occur in the center of a very well built "log-cabin" fire.  I have melted my fair share of iron and aluminum pie makers, though the handles have survived.

    I can type more if that is unclear, but it is bed time 16 minutes ago by my clock.
  • If you mean 'the metal used to create the fire box' - no, it won't melt it.  When you buy a fire box insert for your masonry furnace the fire box doesn't have a limited lifetime, it is expected to last as long as the furnace does. 

    I suppose if you mean 'can we make that metal box ourself out of soft steel' you might have a point, but I didn't know we were talking about that, no more than we're talking about creating fire bricks.  

    CEB on the outside of a refractory masonry stove kit using commercial components I understand as the proposal.
  • This is some HOT issue. Lol.
    Mild steel or even bis-alloy 350 will not melt at the 250-350 degree C. Red hot is about 800 deg. C.
    Steel will "erode" if used as a boiler with water jacket, the moisture from the timber will cause creosote and this etches the steel slowly. So boilers have a set life span. But is repairable. most modern boiler are now gasifier type; the timber fumes are fan forced down into a porcelain chamber where the fumes burn at about 1300 deg.C !! WOW. No emissions to the air. These fumes can run engines after being cooled.
    This topic is a gas, man.

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