[pure-silver] Re: D-76 and variations

As a side note:

Some PET bottles are not straight PET. Coca Cola for example is using
plastic bottles made from a co-extrusion or co-injection process, which
contain up to 7 layers of different polymers, aiming to stop gas
permeability and maintain the 'fizz' over a long time. The tiny bottles are
later heated and blow-molded into their final shape.

However, I don't know how resistant Coke bottles are to darkroom chemicals
compared to the typically used polyethylene bottles.

If I remember correctly, Coca Cola had a patent for this process, and it is
now used to mold automotive plastic fuel tanks.





Regards



Ralph W. Lambrecht

http://www.darkroomagic.com







On 2005-11-29 19:58, "John Black" <jblack@xxxxxxxxx> wrote:

> Some plastics are indeed quite gas permeable.  I don't know which are the
> best but PETG seems to be almost as good as glass.  Glass is however cheap,
> plentiful and reusable.  I use glass and shall continue to do so.


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