Comment

Comment by Francois Lemmer on January 4, 2011 at 8:00am

Hi Michelle

i am not 100% percent sure but i bought the liner from Rino plastics.

2mm thick and it came in a 3mx30m roll.(hdpe i think)

http://www.rhinoplastics.co.za/

from catolog.(below)

Geomembranes (Dam Lining)
Applications
Mining - for prevention of contamination of the soil and underground water table
Tanks – Used as secondary lining for prevention of pollution in the case of leakage or chemical spill
Waterproofing of buildings and construction projects
Evaporation basins
Aquaculture - Water reservoirs for fish breading
Agriculture – Lining of dams for irrigation
Selection of Membranes


HDPE – this material offers the highest tensile strength, impact, tear and puncture resistance. It has very good ESCR (Environmental Stress Cracking Resistance) and the highest resistance to chemicals. Its disadvantage is its rigidity which makes handling and installation more difficult. HDPE is the preferred choice in landfills lining, insulation of chemical plants, roads, petrol stations etc. as well as in mining, due to its chemical resistance.


LDPE/LLDPE – These materials have good mechanical properties and are more flexible than HDPE so they can be handled easier. The new generation of LLDPEs such as metallocenes, match HDPE in strength while maintaining an excellent flexibility. They constitute, therefore, good alternatives where a very high chemical resistance is not essential.


EVA – This material has the highest flexibility of all polyolefin liners and is often preferred as replacement of PVC membranes. Its disadvantage is its low softening point, which makes it unsuitable for use in warm climates without covering. Various types of co-extruded EVA membranes are produced with Vinyl Acetate level between 9% and 18% (the higher the VA level the more elastic the membrane but the lower the softening point) as well as combinations of EVA with LDPE and VLDPE to take advantage of the useful properties of both materials.


FPP – Flexible polypropylene is a new polymer with an exceptional combination of characteristics : very good mechanical properties, excellent ESCR, flexibility superior to polyethylene, excellent weld ability and reparability, lighter weight per sq.m., very low coefficient of linear thermal expansion and higher friction coefficient permitting stabilization of soil at a steeper angle. These advantages make it an optimum choice for many  

Comment by Michelle Silva on January 3, 2011 at 11:54am

I can tell they are cut off from something, but I didn't know what you used for your grow trays. Thank you. Were these repurposed from something prior?

Comment by Francois Lemmer on January 3, 2011 at 9:07am

Hi Michelle

if you look closely you should see that it is the cut offs from when i made my grow trays

200 x 2 mm flat plastic no base and bringing ends together and fixing.

i used them for the fish not to get to the duckweed.

 

 

Comment by Michelle Silva on January 2, 2011 at 6:08am

What is the duckweed growing in..is it rubber?