[Ferro List] Re.: Peter's project

[Christopher Glasspool]

Peter,
When I did my project with perlite, the ratio of 1.5 volume of perlite times mortar produced a material with neutral buoyancy, when tested in the tub. That is about the density of a hard wood. If you go on the website for the perlite company, they have a chart with different ratios for different effects (if still there). I think the ratios would bear out almost the same. Mine was a sculptural application though.
If this was a hollow wall scenario then I wouldn't use any binder and figure out a way to just let gravity do the trick, as why use binders when not needed. If Your looking for a mix that will transfer loads between two skins then I would stay with the OPC, but wouldn't use flyash unless it was cheaper than the OPC. If you were looking for this connecting the outside skins together scenario then I would keep the water content of the mix low as when it shrinks the bond between the skins is gone, especially in a poured grout situation. It may be easier to build up one or both surfaces in strength to the point that the need for stress skin joining isn't necessary, then the binder could be clay, which has both environmental and workability for the solo player attributes. 
Just this week I found some old sampling I had done by mixing a lime mortar with various ratio of wood shavings. These were approximately five years old , and now very hard, as lime keeps curing over time.
If you were using a foam that wasn't water resistant, or combining with organic materials like paper, wood shavings, ag chaff, or whatever, then I would think about using flyash and acryl 60 to help with the water resistance of the insulation.
Papercrete in it's various recipes is much the same, and I have this cautionary thought; if you put it between two water tight skins (needs time to dry out), then consider that every roof sooner or later leaks to some degree, and if the water can get in but can't get out (think about the EIFS lawsuits), then either a model for mold , or an actual swelling and cracking of the hard outer layers.....or even frost heaving within the walls, and even a severe case where tons of water could accumulate with catastrophic worst case scenario ensuing. Unlikely to be sure but it is good to know thy enemies. While architects figure in perm rating of the interior wall needing to be 1.5 times greater than the outside wall for a residence (much water vapor pressure is produced by modern living), and roofs needing this plus a ventilation space, I see alternative methods often ignoring these evolved methods...my own house for instance.
As you figure out the  needs of the insulation mix...stickiness, insulation value, water tightness, and flexural strength; combined with how to apply, then perhaps I or other here can help more with some ideas.
Regards, chris
Peter said:
Any opinions on how I should mix them? I 
have a mortar mixer with new blades, but I was concerned too jmuch 
mixing in this mixer might break down the bubbles. Would I do better to 
rent a concrete mixer?
Also, and ideas on ratios? I suppose it depends largely on the ration of 
strength to insulation I want.
Thanks
Peter



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