[Strawbale] Lego blocks from Straw

jos stoffels ushipoesie at gmail...
Sat Dec 19 14:26:42 CET 2009

your conclusion is right about the binding material however

I see a great future for developing a machine which is compressing straw
bales in to interlocking blocs
  this is a simple machine it can be placed all over europe avoiding costly
transport and helping all areas
provided de machine can compress suficiently at a tempature between 190 and
220 degrees celsius than it is possible to create a bloc without any
additives the cellulose in the straw under pressure and heat should work as
a binder
i hope i have given you all enough to think

kind regards josstoffels

On Fri, Dec 18, 2009 at 9:03 PM, RT <ArchiLogic at yahoo...> wrote:

> On Fri, 18 Dec 2009 07:07:49 -0500, Marc Huebner <marchuebner at gmx...>
> wrote:
> > Does anybody know what kind of glue the guys from oryzatech are using?
> > This sounds like they are using some kind of thermoplastic!?!?
> The blurb that I saw in the link that Duck Foo'd provided mentioned
> "polyurethane (MDI)" as the binder.
> MDI = Methylene diphenyl diisocyanate ("cyan-ate" as in "cyan-ide"),
> C15-H10-N2-O2
>       fairly innocuous but a potential allergen/sensitiser and in a fire
> the  plast-e-c-chhh will generate toxic smoke.
> But for that matter, many people are allergic to straw (or more precisely,
> the allergens that are often found on straw) and in any fire, it is
> usually the smoke, not the fire that kills.
> That being said, as any woodworker can probably tell you, steam-bening
> wood is a process of softening the lignin binding the wood fibres
> together, thereby allowing the fibres to slide past one another during the
> bending process without fracturing the wood and upon cooling, the lignin,
> like a thermoplastic, solidifies again, fusing the fibres together again
> and retaining the bent shape.
> I would have preferred to see the Oryzatech people utilise the straw's
> lignin as a natural binder rather than the plast-ecch!
> one but I suppose that there's be a trade-off in terms of manufacturing
> energy required.
> I'm not too fussy on the blocks being designed to accommodate steel rebar
> and concrete in the cores for stiffening either in the same manner that
> foamed plast-echhh! stay-in-place insulating concrete forms (ICF) are
> erected.
> Baleheads long ago learned that core-stiffening elements like rebar or
> threaded rod placed at the neutral axis of the wall section is the least
> effective placement for those elements, not to mention that placement at
> that location is a major pain in the butt (PITA).
> I think that Oryzatech would have been better off simply keeping the block
> cores solid and perhaps providing a series of surface channels which could
> be used to accommodate exterior tensioning elements (if preferred over
> simply using tensioned mesh) and/or electrical wiring.
> and elitalking <elitalking at hughes...> wrote:
> > I am wondering how tight the construction is.  Is it relying on the
> > stucco or other layers to provide air barrier.  It mentioned structural
> > qualities. Is exterior sheathing required?  Does the rigidity of the
> > interlocking elements sufficient to provide lateral bracing?
> Having never seen one of the blocks and assuming that the pee-you binder
> fills the interstitial voids between the straw fibres, I suppose that if
> one were to dip the blocks into a clay slip before setting in the same
> manner that Meathook (aka Norbert Senf) dips and sets the firebrick for
> his masonry heater cores, the combination might be relatively air-tight
> but I suspect that the wall system would still require a wet-applied
> plaster in order to provide an effective air-seal.
> I suspect that non-seismically-active areas, in-plane shear wouldn't be
> much of an issue, and at most, some diagonal tension straps at the
> building corners might be required.
> Out-of plane lateral resistance... ehhhhh, maybe not so much. I'd be
> inclined to mimic the exterior tensioning systems developed for real
> strawbale construction.
> I like that someone is looking at utilising straw to make a more uniform
> building block than the toilet-paper-for-livestock
> bales that straw builders are using now, however at this point, I'm not
> convinced that Oryzatech has got it right yet. Maybe their Beta version
> will be closer ?
> Years (decades ?) ago, a Quebecer (Louis Gagnon of the concrete + bales
> honeycomb wall fame) took the approach of modifying a standard baler to
> produce better-quality building bales. [Mentally balancing/comparing a
> Louis Gagnon modified baler all-straw bale in one hand vs an Oryzatech
> plast-echhh! + straw legoBale in the other]
> And according to the Oryzatech promotion blurb, their 15 lb per cu ft
> block yields a wall that is triple the R-value of a conventional 2x6 wall
> ?  While I suspect that the polyurethane content may contribute something
> to enhancing the R-value of unadulterated straw, I strongly doubt that it
> enhances it to the point of providing almost R-60 in Murrican units
> ft^2*hr*degF/Btu (or  RSI 10.57 in metric units m^2*degC/W ).
> === * ===
> Rob Tom
> Kanata, Ontario, Canada
> <A r c h i L o g i c  at  Y a h o o  dot  c a >
> (manually winnow the chaff from my edress if you hit "Reply")
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