"Gunner" wrote in message
...
On Sun, 12 Mar 2006 04:30:49 GMT, "Carl Ijames"
wrote:

Most applications will be for air, in an oily
environment, though a
few will be for hydraulic fluids. Is there
some material best suited
for general use?

And will they degrade in a short period of
time, in the back of my
service truck in hot weather?

What material should I be using?

I will likely purchase from ebay one of those
400 piece selections
for $10 or so, unless someone has better
suggestions.

I think Viton is hard to beat as the best
general purpose material to
stock. More expensive than Buna or nitrile but
much more chemically
resistant when you need that. I don't think
I've ever run into an
application that called for Buna or nitrile that
Viton wouldn't work in,
and I've had several applications that called
for Viton either for
chemical resistance or high temperatures or low
outgassing in a vacuum
system. Probably safe for a year or three in a
truck toolbox, at least.
It will eventually start to check and then crack
when you flex it so it
will be pretty obvious when it's time to toss
them. The Parker catalog
is a great resource on materials and especially
on oring groove design.
www.mcmaster.com has a great selection, as well
as www.sisweb.com (as
someone else mentioned - I've bought several
items from them over the
years and think a lot of them, but I am friends
with the owners :-)).

Thanks Carl..exactly the sort of answer I was
looking for.

Respects

Gunner



I agree with Carl. The Viton "o" rings are pretty
much impervious to most common oils and common
industrial chemicals. The extra cost will be
repaid in reliability. If you want to maximise the
shelf life of them, keep them in a dark, sealed
container.

Tom