Nylon fasteners for heat pump grill?

This is a very minor issue, but this group gives such great advice I thought I'd ask anyway.
The metal nuts and washers securing the grill on the outside unit of my heat pump rust over time. Not a big a deal. I just replace them.
However, I was wondering if I could use nylon washers and nuts instead. They wouldn't rust and they might help to dampen vibrations from the grill. Right now there is a metal flat washer, a lock washer, and a nut. I didn't see any nylon lock washers so I'd be using a nylon flat washer, a metal lock washer, and a nylon nut,
Here's a picture of the outdoor unit and the nylon washers and nuts.
http://i108.photobucket.com/albums/n39/wgdus/Heat-pump-fan-grill.jpg
http://i108.photobucket.com/albums/n39/wgdus/Nylon-washers-nuts.jpg
In general, are nylon fasteners just as good (or better?) than metal for outdoor applications subject to weather?
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they will break down from the uv.
use stainless steel ones.
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wrote:

The white/natural nylons will, but I would expect the black nylon will last quite some time. The nylon is pliable enough it will hold w/o the lock washer I think.
Alternatively, you might look at replacing the bolt/nut w/ a expansion stud like used on automotive panels. Might be an issue if the panel must be solidly bolted to avoid vibration noise.
SS obviously is one alternative, of course, agreed...
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I second the stainless steel opinion. They hold up fine on boats. They'll work in your situation.
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