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Reflection-proofing a VP2 wind vane

Discussion specific to Davis weather stations
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martinu
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Reflection-proofing a VP2 wind vane

Post by martinu »

A weird one...

I've got my VP2 wind vane/anemometer unit mounted on my TV aerial pole. A neighbour (who lives due north of me) came round to complain that she keeps seeing flashes from my wind vane as it reflects the sun when it swings in the wind. Leaving aside how someone north of me can be seeing reflections of the sun which is always in the west/south/east sky, has anyone ever had to reflection-proof their vane? Is there a matt-black paint that would stick to the shiny plastic of the vane and wouldn't wash off? Once I get a TV aerial man to move the wind unit higher up the pole so it's not so close to the ridge of the roof, it will be out of my reach (unless I borrow a much longer ladder than I have) so I won't be able to reach it to repair the paint in the future.
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mcrossley
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Re: Reflection-proofing a VP2 wind vane

Post by mcrossley »

Good job you haven't got one of those super shiny rotating chimney cowls! :lol:

But think about the geometry, it is perfectly possible to reflect the sun to your North.
martinu
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Re: Reflection-proofing a VP2 wind vane

Post by martinu »

mcrossley wrote: Sun 11 Apr 2021 2:47 pm Good job you haven't got one of those super shiny rotating chimney cowls! :lol:

But think about the geometry, it is perfectly possible to reflect the sun to your North.
Yes it is a good job I haven't got a cowl. She said she had to draw the blinds in her conversatory whenever it was sunny. To begin with she thought it was a camera flash that kept being fired.

I'm sure if the sun is near the east/west, there are some angles which will point its reflection north. Less likely (but certainly not impossible) compared with viewing from the south, and impossible nearer to mid-day.

I stood in our garden today (on the south side) as it was sunny. And as the vane turned about in the wind, I saw - no flash at all, even when the angle would have been about right. But maybe I wasn't high enough.

I am reminded of a Dick Francis book in which a large mirror, carefully angled for time of day, was used with the intention of blinding the jockeys in a horse race and causing a major pile-up.


I feel a *bit* guilty (but only a bit) and I want to at least try to rectify it - but only if I can do it easily and permanently. I imagine a "sock" of matt black plastic over the shiny tail of the vane would affect its response to wind. I'm sure it's carefully designed to be slightly biassed to one direction (so it points north rather than south, for example) and anything on the surface could affect that.

Matt black emulsion paint - I wonder if it would stick to very shiny, probably water-repellent, plastic.
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ConligWX
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Re: Reflection-proofing a VP2 wind vane

Post by ConligWX »

I'm wondering what happens when the sun comes through her windows without reflection, who does she blame then?
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Ned
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Re: Reflection-proofing a VP2 wind vane

Post by Ned »

Primer for plastic is available in spray cans (in this part of the world anyway) which provides a secure base coat for a matte top coat.
Black might get too hot in the sun though.
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ConligWX
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Re: Reflection-proofing a VP2 wind vane

Post by ConligWX »

or try matt lacquer, or better still use some wet and dry sand paper and take the shine off the vane
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beteljuice
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Re: Reflection-proofing a VP2 wind vane

Post by beteljuice »

Of course it all depends on the time of year - ie. the altitude of the Sun in the sky as well.
Although a conservatory is a large target !
It may be that when you raise the anny array the problem goes away ?

You could try lightly sanding the vane, just enough to take the shine off.
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martinu
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Re: Reflection-proofing a VP2 wind vane

Post by martinu »

Ned wrote: Sun 11 Apr 2021 9:39 pm Primer for plastic is available in spray cans (in this part of the world anyway) which provides a secure base coat for a matte top coat.
Black might get too hot in the sun though.
I only suggested black paint because the vane is already black plastic.

Sanding the vane is a good first step that I hadn't thought of, and would probably provide a good "key" for black paint if that proved to be necessary.
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