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<TITLE>Re: [GSBN] Hand Compressed bales</TITLE>
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<BLOCKQUOTE><FONT SIZE="2"><FONT FACE="Arial"><SPAN STYLE='font-size:10pt'>(Note: I sent this three days ago, but just realized I sent it to myself (!!), so I’m resending.)<BR>
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</SPAN><FONT SIZE="2"><SPAN STYLE='font-size:10pt'>Hello Andy,<BR>
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I’ll add to this from my work, along with Andy Mueller, with manually made bales in Haiti.<BR>
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My experience with Darcey and manual bales in Pakistan transferred very well to the environment in Haiti. We had a steel compression mould fabricated similar to the ones PAKSBAB uses. After a fruitless search for a farm jack in Haiti (though I was told they exist) we imported two from the US. We considered using car or truck jacks commonly available in Haiti, but couldn’t see how they could work well. Farm jacks (48” is a good size) work very well for this purpose.<BR>
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The compression mould design Darcey gives you is a great start. You may or may not see ways to improve it for your circumstances after using it. Making a compression mould offers the opportunity to make the bales any size. I think the 1’x1’x2’ (30cm x 30cm x 60cm) bales are just right for Pakistan and will work well for you in Lesotho, which appears to have a climate similar to northern Pakistan. That size bale is thick enough to provide good insulation (R-24?), but small enough that it doesn’t consume too much straw and is easier to transport and handle, and keeps the cost down. It’s a good balance. Haiti’s tropical climate doesn’t demand the same level of insulation (though insulated walls help keep the interiors cooler, or warmer in high altitude winters), and we considered making the bales even smaller. We might try 10”x10”x20” bales or even 8”x8”x16” (a standard concrete block dimension that is the predominant building material in Haiti). But each time we discuss this we speculate the wall system will be too unstable, even if only during construction, and it would increase labor in handling. <BR>
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Whatever size you choose, having a 1:2 ratio of width to length is important for turning corners. A 1:1 ratio of width to height allows bale orientation “flat” or “on-edge” in the same wall, if exposing or not exposing the ties has an advantage of disadvantage. The small footprint of these bales requires consideration of the wall system you may not be accustomed to, both during construction and for its performance as a finished system. I believe South Africa is in a relatively low-risk seismic zone, but the system still needs to be well-designed for all of its structural demands. The small footprint, with minimum 8 ft. wall height, seems to require a system of through-tied external pinning, both during construction (after four courses the stacked bales become too unstable) and for out-of-plane stability as a finished system. Bamboo works very well for this purpose, though wood or other materials can be used if bamboo isn’t available. Of course plaster type and whether it is reinforced or not is an important part of this as well.<BR>
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Finding the right twine can be a minor challenge. Something that is strong enough and not too costly. In Haiti we’ve brought in US poly baling twine, or used poly twine in Haiti that is four times as expensive, but will next investigate sisal twine that we know is made in Haiti.<BR>
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Regarding density I would aim for a bale weight of 7-8 lbs/cu.ft. So a 1’x1’x2’ bale would weigh 14-16 lb (6-7 kg). You can judge by feel if you want to make them denser. I looked at my data on the relationship between field area, loose straw volume, and compressed bale volume but it’s not adding up. I’ll have to study it further, but I remember about a 6:1 volume ratio of loose straw to compressed bale. <BR>
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The Haitian men who have made our bales developed a technique of folding a fist full of lengths of straw into thirds and pressing these clumps of folded straw into the compression mold. Three side-by-side per layer, and alternating the direction of each layer. In the early Pakistan buildings we were simply taking large balls of loose straw and stuffing them into the mould, but it sounds like that has changed based on Darcey’s description of </SPAN></FONT></FONT><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>“sausage-like bundles placed side-to-side in the mould”. That sounds similar to what I described in Haiti. Making the bales with smaller folded clumps yields a good quality bale with few wild ends of straw and provides great “flakes” for filling voids.<BR>
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One other opportunity we took advantage of in making our own bales is to “cast” 2x4s into a number of bales for the top course. After the bales were installed the roof bearing plates fit right into the notches, with no void or stuffing required between the plates.<BR>
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Collecting and drying straw for the bales in Haiti’s climate has been a challenge. It depends on the weather at the time of post-harvest. The straw was cut and dried on concrete slabs that are normally used for drying rice. There can be a week or more where it rains once a day, and it can be a struggle to dry the straw and keep it dry. Storage for either dry loose straw, or finished bales can also be challenging. Not to say these aren’t challenges worldwide for bales, but the tropical climate ups the ante. All that said, we found it all manageable, and that there is a dry season in Haiti to mates well with harvest times.<BR>
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Another issue to contend with is the price of straw. I don’t know how valuable a commodity it is in </SPAN></FONT><FONT SIZE="2"><FONT FACE="Arial"><SPAN STYLE='font-size:10pt'>Lesotho, but initially you will likely pay the lowest market rate. In both Pakistan and Haiti, once it was learned the use of the straw, there were often attempts to raise the price. There is another related issue, of the current utility of straw in your location. Animal bedding, low-grade animal feed, rural building material (thatch roofs, earth plaster ingredient) are the most common uses as I understand it, of un-baled straw in developing countries. In general I believe straw for bales in buildings is at least as high a use as any of those, but it has to be considered in terms of the overall supply and demand of straw. <BR>
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Also, in Haiti I was surprised to learn that the common practice of burning straw serves two purposes. To rid the field of straw to allow the next planting, AND to create “biochar” that reintroduces nutrients into the soil. I don’t know why I had never heard of this before, and I wonder if this is common practice throughout the world. I was told by our land owner partner that if we developed the ongoing practice of taking straw from the fields to make bales, the farmers would need to add other fertilizer (compost, manures, or industrialized), most of them at a cost. The land owner did say that the biochar is not a complete or high-grade fertilizer (manures are the best) but it is still an important part of maintaining healthy soil in Haitian agriculture (it supplies potassium, but not nitrogen). Of course one should also take into account the negative effects on air quality when massive agricultural burns take place, and that might be reason enough to discourage or prevent it. Part of our work is to implement the use of urine diverting dehydrating toilets, and use urine (diluted, great source of nitrogen) and dehydrated solid waste as agricultural fertilizer. This could reduce if not solve the problem I described.<BR>
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There are photos of our bale making in Haiti at www.builderswithoutborders.org (see Project Photo Gallery). I have others if anyone is interested.<BR>
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Andy, I hope this helps, and I’m sure it’s more than you bargained for. When you go upstream from the industrialized bales most of us are accustomed to it opens up other territory. Andy Mueller was also intimately involved in both the fabrication and installation of the bales, so Andy please feel free to comment.<BR>
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Best regards and best of luck with your work.<BR>
<BR>
Martin Hammer<BR>
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On 11/3/11 7:29 AM, "Andy Horn" <<a href="andy@ecodesignarchitects.co.za">andy@ecodesignarchitects.co.za</a>> wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Arial"><FONT COLOR="#008000"><FONT SIZE="2"><SPAN STYLE='font-size:10pt'>Dear Darcey & others<BR>
Some time back in the Dec 2006 Last Straw there was an article about the work of Darcey Donovan and Greg Zaller in an earthquake struck area of Pakistan, where they used hand compacted bales using car jacks to make their bales for some community projects.<BR>
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We have a Hospital project in the icy highlands of the small mountain kingdom of Lesotho, where the locals are growing wheat (organically) and harvest by hand. We intend to build using straw bales and I am looking specifically for information about how best to make and utilize a hand compactor. <BR>
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We did already make up a simple timber mould simply to establish the quantity and hence cost of the supply of the straw that we would likely need to bale with. We used a hacksaw (with a fine steel cutting blade) to cut the straw, placing the cut ends to the outside and thinning ends towards the inside alternately so as to lay it in a regular fashion. We did not try use a car jack as at that stage we were just looking at quantities. The locals sell their straw in bundles for roof thatching. We found that it will take approximately 20 of their bundles to make a single bale.<BR>
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In order for the idea to be replicable we need to keep it as simple but effective as possible. There is a local metal worker who could weld up a mould for us and I am sure we can lay our hands on some car or lorry jacks. I have never been down this road before and have no idea of the finer technicalities of making your own bales. <BR>
-</SPAN></FONT></FONT></FONT><FONT COLOR="#008000"><FONT SIZE="2"><SPAN STYLE='font-size:10pt'><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">Are there certain car or lorry jacks that work better than others?<BR>
-</FONT><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">how to best design the mould?<BR>
-</FONT><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">how best to lay the straw into the mould?<BR>
-</FONT><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">What kind of level of compression is one looking for and how does one establish the right level of compression?<BR>
-</FONT><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">How to get this as efficient as possible?<BR>
-</FONT><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">What can go wrong?<BR>
-</FONT><FONT FACE="Times New Roman"> </FONT><FONT FACE="Arial">etc etc <BR>
I did already try follow John Glassfords link on his web site that he mentioned (see his mail below) in regards to looking at this for th Haiti project, Thanks John ….but would appreciate much more specific detail.<BR>
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The other thing that came up was the possibility to make thinner bales for internal walls ….but again I have had no experience with this.<BR>
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</SPAN><FONT COLOR="#008000"><FONT SIZE="2"><SPAN STYLE='font-size:10pt'>Any input would be hugely appreciated.<BR>
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</SPAN><FONT COLOR="#008000"><FONT SIZE="2"><SPAN STYLE='font-size:10pt'>Many thanks<BR>
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</SPAN><FONT COLOR="#008000"><FONT SIZE="2"><SPAN STYLE='font-size:10pt'>Andy Horn<BR>
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<FONT COLOR="#008000"><IMG src="cid:3403512415_16012278" ><BR>
</FONT></SPAN></FONT><FONT FACE="Times New Roman"><SPAN STYLE='font-size:12pt'>G ' day Balers<BR>
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Sounds good to me bales for Haiti. Remember it was an earthquake and if you have not seen the work been done by Darcy Donovan here is a story posted some time ago now:<BR>
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(Just scroll down)<BR>
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<a href="http://glassford.com.au/main/?paged=5">http://glassford.com.au/main/?paged=5</a><BR>
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Also you must all have seen the video of the test done in Reno:<BR>
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<a href="http://imedia.unr.edu/shakertables/straw_bail_house_test_270.mov">http://imedia.unr.edu/shakertables/straw_bail_house_test_270.mov</a><BR>
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I love the hand baler that the Pakistanis are using.<BR>
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Seeing there is high unemployment in Haiti and if there is any rice straw in the paddocks then the hand balers would work.<BR>
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Anyone know how Darcy is going last time I heard Darcy was still in Pakistan?<BR>
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Kind regards<BR>
The Straw Wolf<BR>
Huff 'n' Puff Constructions<BR>
<a href="http://www.glassford.com.au">http://www.glassford.com.au</a><BR>
61 2 6927 6027<BR>
In Australia (02) 6927 6027<BR>
<BR>
Mountains of the Moon 2011<BR>
<a href="http://www.mountainsofthemoon.org">http://www.mountainsofthemoon.org</a><BR>
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