<< Mail response from Smile Plastics | D70Interviews | Mail response from Levien van Zon >>

Hi Martin,
you are asking for a 20 page report !!!
I make my living out of plastics consultancy work, specialising in recycling, so you are asking me to do all this for fun :-) Ahh, well, I suppose I can spend a few minutes more on this, but I would like you to understand that if you get this project, then please include a sum of money for extracting information out of Colin Williamson.
Stacking bags filled with debris relies on the weather resistance, esp. U.V. of the bag- very important factor. Shingles from cartons does work, but you can see the better (high tec) solution with Tetrapak product Tectan.
The technique we developed in CR did not produce luxury goods, it produced very utilitarian goods, but appropriate for the country and the waste.. I still think that if the available resource is dirty contaminated waste plastic and cheap labour, then the output of putting the 2 together could be cleaner, sorted waste plastic with a financial value to sell on elsewhere, or to convert to plastic sheeting using a bit of technology (but not much)

• Can you tell us more what plastics we are aiming for, polyethylene is that the thin carrying bags?
  yes, any thin plastics film (foil ?) or sheeting can be converted
• How does the extruder work, and how do the banana bags get involved?
  you'll have to go on the net to discover this possibly starting with http://www.sdplastics.com/plastics.html or via sci.polymers banana bags are used in the growing of bananas and are scrapped on harvesting - thousands of tons of them
• For the future I would be interested in replacing the firewood by solar power, how does that sound?
  never tried it but you need to achieve a temperature of maximum 250 C
• What material should the moulds be from, to prevent the substance from sticking?
  sheet steel is easy and cheap. It wont stick if you get it right, or use a little grease - ideally silicone spray !!
• If we come up with some sort of a press, like a grape press or olive oil press with bolts ends (is it called thread ends?) and a flywheel or something, will we ever be able to produce enough pressure manually to press anything at all?
  this would produce a good pressure for forming pre-melted plastic but you need up to 1 ton per square inch to replicate my process - sorry, that's about 150kg per sq cm, but if you are in Sri Lanka I bet they understand psi !!
  And perhaps you have some more tips for plastics that can be used, and possible end products, this is the difficult one - you have to go around the area looking and thinking and understanding plastics processing technology and something will come out of it. I'd recommend a good local plastics man to help you.