In article ,
"Geoffrey W. Schultz" wrote:

I have a KISS wind generator wind generator that develops vibration at
certain wind speeds. The problem is that there's a PVC fitting that goes
over a 2" stainless schedule 40 support pipe that is loose fitting. I want
to machine one with a sleeve bearing on a lathe and make it out of plastic.
However, I really don't have any experience machining plastic, I've been
looking at www.mscdirect.com under Raw Materials/Plastic Material/Rods for
3" material. To keep costs under control I'm looking at the following:

Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall strength of
these would be greatly appreciated.

-- Geoff


I know nothing of Acetal or UHMW (until reading this message, not even
the fact that they existed) but I can tell you with certainty that the
UV resistance of PE (Either HD or LD "flavors") is pretty much
nonexistent. They'll both "brittle up" and start to crumble in short
order. Depending on the thickness, coloring (if any), exact amount of
exposure, intensity of the UV source, and so on, they may start showing
signs of problems in just a few hours, or they may stand up for a few
days, but they *WILL* disintegrate into a worthless scattering of
plastic dust in far less time that what you're likely to call
"acceptable" for your application.

Nylon also gets a bit weird when left in the sun, but not in every case,
so I would presume there are variations (probably from additives aimed
specifically at altering UV characteristics) within the overall
type-designation "nylon" that have at least some UV resistance.

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