<div>your conclusion is right about the binding material however<br> <br>I see a great future for developing a machine which is compressing straw bales in to interlocking blocs<br> this is a simple machine it can be placed all over europe avoiding costly transport and helping all areas<br>
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<br>
i hope i have given you all enough to think</div>
<div><br>kind regards josstoffels<br><br></div>
<div class="gmail_quote">On Fri, Dec 18, 2009 at 9:03 PM, RT <span dir="ltr"><<a href="mailto:ArchiLogic@yahoo...">ArchiLogic@yahoo...</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote">On Fri, 18 Dec 2009 07:07:49 -0500, Marc Huebner <<a href="mailto:marchuebner@gmx...">marchuebner@gmx...ch</a>><br>
wrote:<br><br>> Does anybody know what kind of glue the guys from oryzatech are using?<br>> This sounds like they are using some kind of thermoplastic!?!?<br><br><br>The blurb that I saw in the link that Duck Foo'd provided mentioned<br>
"polyurethane (MDI)" as the binder.<br><br>MDI = Methylene diphenyl diisocyanate ("cyan-ate" as in "cyan-ide"),<br>C15-H10-N2-O2<br> fairly innocuous but a potential allergen/sensitiser and in a fire<br>
the plast-e-c-chhh will generate toxic smoke.<br><br>But for that matter, many people are allergic to straw (or more precisely,<br>the allergens that are often found on straw) and in any fire, it is<br>usually the smoke, not the fire that kills.<br>
<br>That being said, as any woodworker can probably tell you, steam-bening<br>wood is a process of softening the lignin binding the wood fibres<br>together, thereby allowing the fibres to slide past one another during the<br>
bending process without fracturing the wood and upon cooling, the lignin,<br>like a thermoplastic, solidifies again, fusing the fibres together again<br>and retaining the bent shape.<br><br>I would have preferred to see the Oryzatech people utilise the straw's<br>
lignin as a natural binder rather than the plast-ecch!<br>one but I suppose that there's be a trade-off in terms of manufacturing<br>energy required.<br><br>I'm not too fussy on the blocks being designed to accommodate steel rebar<br>
and concrete in the cores for stiffening either in the same manner that<br>foamed plast-echhh! stay-in-place insulating concrete forms (ICF) are<br>erected.<br><br>Baleheads long ago learned that core-stiffening elements like rebar or<br>
threaded rod placed at the neutral axis of the wall section is the least<br>effective placement for those elements, not to mention that placement at<br>that location is a major pain in the butt (PITA).<br><br>I think that Oryzatech would have been better off simply keeping the block<br>
cores solid and perhaps providing a series of surface channels which could<br>be used to accommodate exterior tensioning elements (if preferred over<br>simply using tensioned mesh) and/or electrical wiring.<br><br>and elitalking <<a href="mailto:elitalking@hughes...">elitalking@hughes...</a>> wrote:<br>
<br><br>> I am wondering how tight the construction is. Is it relying on the<br>> stucco or other layers to provide air barrier. It mentioned structural<br>> qualities. Is exterior sheathing required? Does the rigidity of the<br>
> interlocking elements sufficient to provide lateral bracing?<br><br>Having never seen one of the blocks and assuming that the pee-you binder<br>fills the interstitial voids between the straw fibres, I suppose that if<br>
one were to dip the blocks into a clay slip before setting in the same<br>manner that Meathook (aka Norbert Senf) dips and sets the firebrick for<br>his masonry heater cores, the combination might be relatively air-tight<br>
but I suspect that the wall system would still require a wet-applied<br>plaster in order to provide an effective air-seal.<br><br>I suspect that non-seismically-active areas, in-plane shear wouldn't be<br>much of an issue, and at most, some diagonal tension straps at the<br>
building corners might be required.<br><br>Out-of plane lateral resistance... ehhhhh, maybe not so much. I'd be<br>inclined to mimic the exterior tensioning systems developed for real<br>strawbale construction.<br><br>
I like that someone is looking at utilising straw to make a more uniform<br>building block than the toilet-paper-for-livestock<br>bales that straw builders are using now, however at this point, I'm not<br>convinced that Oryzatech has got it right yet. Maybe their Beta version<br>
will be closer ?<br><br><br>Years (decades ?) ago, a Quebecer (Louis Gagnon of the concrete + bales<br>honeycomb wall fame) took the approach of modifying a standard baler to<br>produce better-quality building bales. [Mentally balancing/comparing a<br>
Louis Gagnon modified baler all-straw bale in one hand vs an Oryzatech<br>plast-echhh! + straw legoBale in the other]<br><br>And according to the Oryzatech promotion blurb, their 15 lb per cu ft<br>block yields a wall that is triple the R-value of a conventional 2x6 wall<br>
? While I suspect that the polyurethane content may contribute something<br>to enhancing the R-value of unadulterated straw, I strongly doubt that it<br>enhances it to the point of providing almost R-60 in Murrican units<br>
ft^2*hr*degF/Btu (or RSI 10.57 in metric units m^2*degC/W ).<br>
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<div class="h5"><br><br><br><br><br>=== * ===<br>Rob Tom<br>Kanata, Ontario, Canada<br><A r c h i L o g i c at Y a h o o dot c a ><br>(manually winnow the chaff from my edress if you hit "Reply")<br>__________________________________________________<br>
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