coming from the cd manufacturing industry, I have the following comment:
The alu-layer on a cd is covered with a lacquer to prevent any oxidizing or "fungi-attack". This layer could be of lousy quality (too thin) but more likely, it could be wrong applied in the manufacturing process. It is applied using spinning chucks. it's layer-thickness depends on spinning speed, accelaration and time.
Since the lacquer is dispenced from the inner diameter, it is impossible to cover the cd 100%. The inner most area, close to the innerhole, is not covered, since it has to be hold by a chuck-pin to center the cd for the application of the laquer. Therefore, any cd, which has an alu layer which covers the entire cd upto the innerhole, does not have protection on the aluminium for 100%. The outside air can reach the alu-layer easy!
Usually on the outside, there is a small area of uncovered poly carbonate and with the lacquer application this should be 100% covered with the transparant lacquer. Some manufactures however, like to speed up their production times by "tuning" their process as short as possible. It is possible that they cut the spinning time too much and leave some outside area uncovered. Your cd will not reach the 10 years with that! An easy check can be done by inspecting the cd's 1.2mm side. If the cd has 90 degree edge on the outside diameter, a wave-form of lacquer can be seen. The "rounded" outer-diameters are difficult to inspect.
Further more, this lacquer is dryed (cured) by uv light (these days in some 1.5 seconds). The UV-lamps doing this job have only about 1000 hours of effective UV-light available. Some reluctant manufactures leave the lamps in too long and that makes the lacquer layer of lousy quality as well.
DVD's are less much less of a problem since the reflective layer lies deep within the polcarbonate it self.
10 years of breakeven because the invested money is too low. There's a report from greenpeace about an investment from shell, saying that if the investment, for a just opened factory, was seriously (they invest a lousy 55 million or so)around 700 million, their claim of 10 years needed to be competitive with oil-prices, would be reduced to zero (so immediately competitive!).
As long as the oil companies are the ones who control the solar panel technology, the size for car-use-panels will be too big until they decide it is time too shrink it...
Slashdot Mirror
coming from the cd manufacturing industry, I have the following comment: The alu-layer on a cd is covered with a lacquer to prevent any oxidizing or "fungi-attack". This layer could be of lousy quality (too thin) but more likely, it could be wrong applied in the manufacturing process. It is applied using spinning chucks. it's layer-thickness depends on spinning speed, accelaration and time. Since the lacquer is dispenced from the inner diameter, it is impossible to cover the cd 100%. The inner most area, close to the innerhole, is not covered, since it has to be hold by a chuck-pin to center the cd for the application of the laquer. Therefore, any cd, which has an alu layer which covers the entire cd upto the innerhole, does not have protection on the aluminium for 100%. The outside air can reach the alu-layer easy! Usually on the outside, there is a small area of uncovered poly carbonate and with the lacquer application this should be 100% covered with the transparant lacquer. Some manufactures however, like to speed up their production times by "tuning" their process as short as possible. It is possible that they cut the spinning time too much and leave some outside area uncovered. Your cd will not reach the 10 years with that! An easy check can be done by inspecting the cd's 1.2mm side. If the cd has 90 degree edge on the outside diameter, a wave-form of lacquer can be seen. The "rounded" outer-diameters are difficult to inspect. Further more, this lacquer is dryed (cured) by uv light (these days in some 1.5 seconds). The UV-lamps doing this job have only about 1000 hours of effective UV-light available. Some reluctant manufactures leave the lamps in too long and that makes the lacquer layer of lousy quality as well. DVD's are less much less of a problem since the reflective layer lies deep within the polcarbonate it self.
10 years of breakeven because the invested money is too low. There's a report from greenpeace about an investment from shell, saying that if the investment, for a just opened factory, was seriously (they invest a lousy 55 million or so)around 700 million, their claim of 10 years needed to be competitive with oil-prices, would be reduced to zero (so immediately competitive!).
As long as the oil companies are the ones who control the solar panel technology, the size for car-use-panels will be too big until they decide it is time too shrink it...