[TR] POR15 and UV

[Alan Myers]

 Hi Mark,

I imagine it makes a difference what color you use, and how much it actually
gets exposed to UV.

I used some silver metallic POR15 inside and on some relatively hidden areas
of a set of chrome motorcycle fenders. The rest of the fenders were chrome and
polished back up. Some of the hidden areas and the underside had some small
rust pits, hence the POR15.

Over time the areas that got the most sunlight on them got tinted a bit
golden/yellow.

Meanwhile, my car frame has been painted with black POR15 for years and shows
no discoloration. It could just be that it's not possible to see on the black.
But also the frame under the car only ever gets indirect sunlight.

So, your engine compartment is unlikely to see very much sunlight, unless you
are constantly showing off the engine and displaying the car. So, I wouldn't
worry too much.

I probably won't use POR15 again. It's impossible to spray for a nice finish
and next to impossible to remove, or to feather sand and retouch if it's ever
needed. (Note: a welding torch will burn it off eventually, but it holds up
surprisingly well!) I am not sure what might be expected to stick on it as a
top coat, either. Plus if you get the stuff on your skin, you basically have
to wait until it wears off.

Cheers!

Alan Myers
San Jose, Calif.
amfoto1 at aol.com
'62 TR4 CT17602L
http://www.triumphowners.com/640




I know from POR's documentation that POR-15 is succeptible to discoloration
from excessive UV exposure. The question is how much?

Over the past year or so, I have been slowly working my way through the
engine
bay (painted black these many years) and scrubbing down surfaces and
fittings.
I've been applying POR with very pleasing results. However, I have not been
top-coating.
The part I did last year still seems perfectly fine. The car is indoors most
times. Is it a very gradual greying, or is the engine bay protected enough
that I can leave it bare POR coated as it is? I quite like the present
surface
and semi-mid gloss that comes with the material. Just don't feel like having
it suddenly go all grey on me.

Mark Hooper
1972 TR6.