On Mon, 04 Oct 2004 04:43:54 GMT, Mac wrote:
On Mon, 04 Oct 2004 02:43:08 +0000, Brian Whatcott wrote:
On 3 Oct 2004 16:17:24 -0700, wrote:
I have long been curious as to why the polymer lights on my boat
become cloudy relatively fast, whether near the sea or not & whether
under cover or not. It polishes off fine with a bit of work, but I
never see this occur in other acrylic or lexan windows I have around
my place, and it is a minor annoyance. Is there one particular type
of clear polymer which clouds up like this? If left for months, they
will become only translucent until repolished.
Here's my guess: most plastics are degraded by the uv component of
sunlight. Acrylic and lexan hold up pretty well. If I recall,
polycarbonate holds up pretty well too.
Lexan is a trademarked name for polycarbonate.
I used some special polycarbonate that had a UV coating on one side and it
seemed to hold up well for the 5 or 6 years I had it on the boat. It
wasn't a lamp cover, though.
//
Ozone (as found in smoggy areas) might attack plastics. It definitely
attacks some types of rubber.
--Mac
Quite right: the two popular transparent plastics are polycarbonate
and polyacrylate
Brian W