Concrete Insulations...

[Reedtb2@cs.com]

Dear EBJ:

What a lifetime of experience.   

Ideally I would like to test a few recipes for insulating concrete or the 
"refractory mortar" you mention. Maybe Gretchen Larson can help.  She  
operates a pottery kiln and made some vermiculite and perlite bricks for me a 
while back.  

We could all use a better high temperature (refractory), high insulation, 
convenient, cheap material.

TOM REED



In a message dated 1/20/01 3:02:05 PM Mountain Standard Time, 
ericbj@club-internet.fr writes:


>   Reedtb2@cs.com a écrit: 
> > Wow, the papercrete sounds great and I too will make some this weekend. 
> > ... 
> > The Asian Institute of technology (AIT) and Bob Reines have been pushing 
> > "ferrocement" as a construction material for gasifiers (and could be 
> > stoves). 
> >  "Ferrocement" seems to be wire mesh with cement around it.  No good stuff 
> > yet on refractory properties.
>
> Ferro-cement : 
> My domestic heating consists of cheap, cylindrical, thin-walled 
> steel stoves burning oak logs, the usual fuel in country areas round 
> here (the foothills of the Pyrenees).  I have lined these stoves using 
> refractory mortar, 'ready-mixed' and doubtless containing high 
> alumina cement, of the type sold by builders' merchants for 
> barbecues etc.  This is built up on the inside of the stove walls on 
> expanded metal lath, which is self-supporting and provides a better 
> key than multiple layers of chicken-wire mesh.  The smallest of 
> these stoves has seen twelve years' service, and last summer I 
> hastily, and probably unnecessarily, patched up some minor cracks 
> in the refractory lining. 
> Advantages of refractory lining in stoves :- 
>      1.   Stove does not glow red hot.  The smallest stove is in my 
> caravan and is within 8 inches of the bed.  (Incidentally, the 
> caravan is strictly non-mobile, being encapsulated in ferro-cement. 
> The motive for this :  it was falling apart ; but it has also greatly 
> improved the comfort.  The very fine steel mesh off old beds was 
> used for this and is ideal ; and free) 
>      2.   Gives a much more constant heat output 
>      3.   Damp wood 'takes' better 
>      4.   More economical, since better control over rate of burning. 
> If wood is dry, stove well heated, and red embers are present, one 
> can burn a single log at a time.  It glows away like a cigar. 
>      5.   Steel walls of stove do not burn through 
>      6.   Continues to give out heat long after the stove has gone 
> out.  With the one in the caravan this is especially so, since the flue 
> pipe at the rear is packed round with the very dense bricks from an 
> old electric night-storage heater, picked up at a scrap yard.. 
> Gas-producers : 
> One of my neighbours, a retired old peasant farmer, who as a 
> young man, in November 1943, took to the maquis to escape 
> forced labour in Germany, tells me the much sought-after fuel for 
> gazogènes (gas producers) fitted to vehicles in those days was 
> 'green' - i.e. unseasoned - beech logs.  As mentioned, the main 
> domestic fuel here is oak logs, preferably seasoned.  He insists this 
> was much the most suitable fuel :  beech, and 'green'.  Could this 
> be because beech is more combustible than oak ? Beech is too 
> combustible to be much good on an open hearth  while oak beams 
> commonly survive a house that burns down. ; they are more fire 
> resistant than steel girders, which twist and collapse.  But why 
> unseasoned ?  Adds steam, to make more gas ? 
> One of the wine 'caves' in Limoux, the nearest town, was still 
> running a gazogène lorry as recently as the early '80s. 
> Insulation : 
> Some years ago, after insulating a cavity wall with lightweight 
> 'concrete', at great expense owing to the cost of the expanded 
> mineral, I turned to using a sawdust-cement mortar to insulate 
> under a floor.  The sawdust was donated free by a local sawmill. 
> Not having time to experiment, I probably used far more cement 
> than was necessary.  Some of the mix left over was left outside in 
> all weathers and showed scant sign of deterioration over years of 
> exposure.  While many commercial insulating materials may have 
> desirably low lambda values while they last, if my experience is 
> anything to go by, they do not last long if there are vermin around. 
> However I have no idea of the resistance to high temperatures of 
> cement-sawdust 'concrete'.