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Demotech News

News Sat Feb 10 (2007) -- Fri Apr 22 (2016)
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News Fri Jan 09 (2004) -- Tue Jan 25 (2005)
News Wed Aug 27 (2003) -- Tue Dec 16 (2003)
News Tue Jun 03 (2003) -- Thu Aug 14 (2003)
News Mon Mar 17 (2003) -- Thu May 22 (2003)

Support for the repair of our roof

Mon Mar 17 (2003)

The south side of the tach roof of our barn (=our workshop) is in bad condition. Out of the blue, two very special people popped up offering help with the repair: Hans de Haas and his son Arjan. Hans has a special practical knowledge of basic handicraft work, such as axing timber out of logs and the construction of roofs in days long past. He did action-research on such technologies as used in the stone age and in medieval periods.

Arjan de Haas has a similar expertise and is involved in a development project in Senegal. One of the technologies he introduced in this project was -to my big surprise- the rope pump! There seems to be plenty of overlapping interests in both our field of work and expertise. I am looking forward to the chance to work together on the roof this week and on other projects later on.
As a contribution to start with, Hans en Arjan donated bundles of reed they loaded on my trailer as the picture shows.

A very nice meeting place

Fri Mar 07 (2003)

Yesterdays one-day fair of the LHUMP proved to be a very productive gathering. Rejo Zenger and I set out to contact students who would like to share our work. More than a dozen students were interested in a followup. During these first contacts students expressed interest in a multi-day stay at the workshop of Demotech to get the feel of the potential the Demotech action-research approach could have for them. We promised to try to organize such a 'design-in'.
Apart from productive, this gathering was also a very nice follow-up of the workshop we did with the LUMPH.
Our stand was situated next to a food bar offering beautiful looking and tasting food. Apart from this food and the free smell of it, we got all the help from the LHUMP-people we needed.
Many students browsed through our website on our computer and used the entry form so we can send them follow-up information. This form is still accessable here.

Fair for internships at the Utrecht University Campus

Mon Mar 03 (2003)

On March 5th, Demotech participates in a one-day fair, organized for students to select and arrange their internships and assignments. However, this fair is dedicated to such assigments and working practices that relate to environmental care and development studies. The initiatieve for this fair is taken by LHUMP, an inter-university platform for the promotion of student commitment to these issues.
For a description of the internships and assignments Demotech offers, click here. As soon as time permits, we'll translate the Dutch text into English.

Senegal and back, small harvest

Fri Feb 21 (2003)

The small result from my visit to Senegal: only four days working in the village Keur Mousse, one week hospitalized in Dakar, two weeks recovery, now back in track in the Demotech workshop. Some impressions are noted here.

During a four days visit to the village Keur Mousse, Ives Fayes showed me the location of his garden project. In one of the neighbouring gardens a well in construction had reached the groundwater level at 35 meters depth. For the last time, boys with a donkey cart fllled the water tank in Ives' garden from which the small fruit trees have been watered up to now. Further irrigation will come from the well.
I met the team of well diggers, that arrived to continue work on Ives well, starting at 17 meters depth. In the mean time they dug it out to groundwater level. They will continue with the construction of concrete rings that they will sink into the water bearing layers.
Ives took me to a carpenter, enthousiastic to assist in constructing the pulley and its support over the well. Ideas developed to make a platform as a well cover. On it a person could stand to pull down the rope, running over the pulley. At each end of the rope a rubber bag is attached. The rubber bag, connected to the part of the rope, lowered into the water down in the well will fill up, while the rubber bag having reached the platform is being emptied into a container placed on the platform. From this higher position of the container, water could run through a hose to plant beds and trees to be watered.
I promised Ives to make a scale model of this setup, that he could send to Keur Mousse, to inspire the carpenter and others that now continue work on Ives' garden project.

Sadly nothing came of the plan to instruct people from Oumar's school how to make the NightReader. However bad I felt because of lost time and opportunities and because of my sick body, it felt so good to receive continues kind support from Ives, his family and his friends. Certainly I owe them an effective continuation of support for their projects.

Travelers' Disease

Sun Jan 19 (2003)

Due to health problems Reinder will not be able to continue his work in Senegal right now.
He is planning to return to Holland as soon as possible.



Sun Jan 12 (2003)

First problem in Senegal is a totally different keyboard configuration. Apart from that, Senegal is the place to be!
Flying over Europe with all cities brightly illuminated, an in between stop at Lisboa, a great down path over this old city, the bay and the bridge. Then the flight over Africa, no lights, until the approach to the airport of Dakar; again as in Europe all streets illuminated and a lot of traffic, notwithstanding the time of the day, three in the morning.
I was welcomed at Omar's house. Planning what to do began with demonstrating the NightReader, the DemoSticks and the pulley. I have not yet got a clear picture of the type of schooling Omar is directing. However the plan is to instruct a team of one electronic repair man, one school teacher; an older student and a lady who will write down the steps taken, as a base for a later to be written instruction how to build the NightReader.
Tomorrow in the earley morning, I travel to the nearby village of Keur Mousse. A small (?) problem could be to find a manually to be turned grinding stone. Hand grinding is well possible, but would take time. Only time is scarce in this project. Cooperation, interest, motivation is ample available. I enjoy immenseley to drive with my friends from one location of the town to an other quarter. So much to see, this world is so much more alive than my own dear country.
I write this in a Internet cafe close to the place where I am lodged. There seem to be plenty of shops like this one, so you can expect more news soon.

A first letter to start a travelreport

Sat Jan 11 (2003)

Dear Friends, A first letter to start a travelreport. Hectic it was with last minute preparations, calm it is now, sitting behind a computer screen at Schiphol Airport. Still plenty time before my plane boards.
The programme is simple and unique.

  • Initiate local manufacture of the NightReader, the storage seat and the pulley. For this Ives and I will go to workshop, order a first model, order more when people get the idea.
  • Sell the gadgets through a friend of Ives. Find out if people like it and how much they are willing to pay for it.
  • Find a NGO who will like to try the DemoSticks, as I brought a bundle of the needed parts. I have to finish, more news from Dakar soon!

    Fast results from simplicity and warming up the winter with a fan

    Sun Dec 22 (2002)

    Target five minutes, we did it! Yes we made it possible. Ives and I made a frame out or two sticks and a block of wood with a groove in which the rubber ring fits. The part of the rubber ring that extends above the groove is cut off. The knife is guided by the top surface of block during cutting. This surface is protected by bits of tin, nailed to this surface.

    I had just a bit of luck to find the proper method without the time consuming trying out of the many potential solutions, that I normally have to tackle. I described the result in my last 'News'. Then again I was lucky with the setup that came up when working with Ives. This setup is shown in the picture. Ives told me he had seen it in a recent dream. This is great, a bit of magic, a bit of proper magic when Africa is apporoaching.

    What is really practical with this aid is the footrest. This is sadly just not shown on the picture, but it is a simple short stick nailed to the two battens. This footrest gives stability and control over the position of the cutting block at the top. With this device it is again possible to cut easy and safe, and without help of a second person. And it works fast!

    Some news this week also on the brick stove. Hans Baarslag build a fan in a box. He and I connected this box to the chimney pipe and fitted it into a window sill. We were too cold and impaitent to properly seal the stove with mud mortar. Thus we lightened a fire in the stove and switched on the fan. There was no smoke pouring out of the many openings, like the first time we put fire to it. But soon there was the welcome warming of the metal covers on the outside of the stove. Half an hour later it felt good to sit on top of the stove. The temperature of the chimney pipe was only luke warm.
    Hans and I decided to forget about making a chimney that would produce enough draft through the stove and further develop forced draft by a fan. This fan could run on electricity, but it also could be propelled by the heat of the stove. A simplified Stirling engine would be ideal for this job.


    The pulley, soon in production?

    Tue Dec 17 (2002)

    That of course is what Ives and I are heading for. But our effort last week to cut the rubber rim of the pulley wheel showed it may take a lot of practice before a person can produce these rims in a quantity and at a speed needed if she or he can make a living out of it. That is, if we do not find an easier way for the cutting.
    Long ago in Bandung/Indonesia Hans Rolloos brought me to the local 'Rubber King'. In this workshop thin strips, that were accurate and totaly smooth, were cut out of car tires at an amazing speed. Just by hand, in combination with a simple but very effective guide for knife and rubber.
    This proves that the actual cutting of rubber should not be the problem and that we have to work out a similar smart setup for guiding knife and the rubber part. So today I made an experimental set up to see if I could copy the Bandung experience to the rubber cutting of the pulley wheel.
    The picture shows a stick, this time clamped into a vice, but that could stand up erect. Attached to the stick is a guide to position the rubber rim in the right angle. Two bits of wood are attached to the stick. They guide the knife. Some soap and water sprinkled on this guiding platform eases the cutting. While cutting, the rim has to be turned and the strip that is cut loose has to be pulled open with some force.
    Time for preparation for the trip of Ives and myself to Senegal is running our, only a few weeks are left. Ives will be here coming Thursday and Friday. I hope he and I can get this system running. The aim is to cut a rim a five minutes.

    Making sheet metal parts for the brickstove

    Wed Dec 04 (2002)

    Use less time to teach more. Better be efficient if you set out to empower people. To teach a practical man like Zuhair this method for cutting and folding sheet metal took only a few minutes, although he was totally strange to this approach.

    The smart trick is to drive the scharp point of an ax along a line marked on some piece of sheet metal. Only the sharp point has to cut through. To let the blade sink deeper in the cut spoils the work.
    The line can be straight, can make curves or sharp angles. It only takes a little practice to follow the line with the sharp front end of the cutting edge. Fast but light hammerstrokes on the flat side of the ax force the cutting.
    The edge of the cut sheet bends inwards. This can be flattened, but folding it over some more, then flattening the double layer, makes the edge stiffer, soft and safe for handling.

    When an 200 liter oil drum is used to recuperate the sheet metal, the cylindrical shaped side part has to be flattened. This works well by pounding it with a log as shown in the picture. Start in the middle and then works towards the ends.

    Folding sheet metal is easy using almost the same method as with cutting. Hammering the ax along, but prevent to make a cut, only make a linear sharp dent in the sheet. Bend over the part that has to be folded. Sometimes it helps to fold over an edge, but with some practice just applying some force and hammerblows does the job.
    A nice property of this method of folding is the accuracy of the place where the sheet folds. You get it exactly at the line that is dented with the ax.


    News Thu Nov 28 (2002) -- Mon Oct 21 (2002)
    News Fri Oct 11 (2002) -- Tue Aug 27 (2002)
    News Tue Aug 27 (2002) -- Mon Jul 01 (2002)