Too_Many_Tools wrote:

On Mar 31, 8:37*pm, "Edwin Pawlowski" wrote:
"John Doe" wrote in message

Looking at plastics like UHMW and delrin... wondering how
important is "UV stabilization" for outdoor use? How long does
it take for ultraviolet light to damage the plastic? Months?

Yes, months but varies with your climate and sun exposure. *If it
is not

specified with UV inhibitors, don't count on it being there.

If a grade is not specified chances are it can vary or be mixed.
*Black molded parts are the best for getting rig of rejected
parts by grinding th
em
and blending in the virgin material.

Edwin is correct.

If you need UV..and any outdoor usage does...pay the money and get
the right stuff.

Do you really have time to do the the job twice?

For the vast majority of projects, I would guess No.

My problem isn't just a matter of cost, I'm going to start with only
about 1 foot of Delrin rod. The problem is trying to figure out what
is UV stabilized and what isn't. I asked McMaster-Carr and they said
they don't have any more information than what is on their website,
the specifications listed with the product. Other online outlets give
about the same information.

My project is experimental and maybe the exposure to sunlight will be
limited enough. It's a first design, and that usually sucks anyway, so
I should probably back off on the UV concern for the moment. If it
works, I'll take the advice and spend more on the subsequent design,
ordering from a more specialized store like the ones that require
minimum line item and total order amounts. But, to begin with, I'd
like to experiment with a short rod of several different Delrin/Acetal
types. The project can actually use more than one type at a time.

Thanks.







--
For what it's worth. I'm making stopgaps for between in-line skate
wheels. The Acetal rod will be underneath and supported by a U-shaped
metal flat bar that rests up against the bottom of the frame on both
sides. The stopgap will be between each pair of wheels, several per
skate (probably starting with just one skate). That's to help keep
obstacles from getting up in between the wheels and causing seizures.