SkyWatcher -Gold plastic!!???????

[Merlin66]

Why is it that all the black plastic parts of my Skywatcher gear is slowly acquiring a gold finish???
The finder, the covers on the HEQ5 - all the black plastic parts.
Seems to be related to UV exposure.......

[torana68]

photo? is it outside in the daylight?

[dannat]

yes i left my blue tube skywatcher at the top of back seta on a hot day & it developed a rusty gold anodised type finish -their paints can't be UV stabilised

[pfitzgerald]

Hi Ken
Have you tried touching other objects to see if you have that Midas touch? ;)
Paul

[OICURMT]

I actually LOL'd and SWMBO asked what I was laughing at... :rofl:

[redbeard]

+1 , the LOL bit, great reply from Paul! :lol:

[Merlin66]

Thanks guys!!!
I'll get a couple of photos later today....
I'm surprised other users haven't seen the same effect......

(No Midas touch here - everything I seem to touch turns to s%^&)

[Merlin66]

"Skywatcher Gold" ???

[RB]

Oh boy, that's terrible !

:confused2:

[DavidU]

I have the same problem, it seems the aluminium parts are dyed not anodized so it fades in sunlight.
http://www.ehow.com/how_8421322_dye-aluminum.html

[ZeroID]

Well at least you've found out they are aluminium and not plastic !! :thumbsup:
Automotive spray cans are your friend .. Satin Black looks nice. :D

[LewisM]

They are anodised (otherwise the dye used in anodising won't adhere to the alu.) - all anodising is is cathodically altering the alu surface then immersing in hot dye to permeate the open crystalline surface.

SW is obviously cheap, non-UV stable anodising dye, just like cheap Chinese clothes I guess.

I had the same on a QHY5 guidecam - anodising turned gold. I resprayed it lurid green :)

[MrB]

It's the anode, hence the name.

You are correct about using cheap dye. Skywatcher probably figured telescopes are used at night so they didn't need to use a lightfast dye.
Black dyes are the most expensive, the black I use is 'Black BK Excel (http://www.usspecialty.com/color.php)' from US Specialty which has good lightfastness (8/10 score) at 20um thickness, fine for my needs, but it costs about twice as much as all the other pretty colours.
If I was anodising for daylight use I would use 'Black HBL' (about 4x the price) but it rates 8/10 at 10um and 10/10 at 25um thickness.

There is a very good article about why black is not black here:
http://www.pfonline.com/articles/when-black-dye-is-not-black

[LewisM]

That'd be correct... brain fart here :)

[traveller]

Or just re-paint it Taka-watcher Sky-hashi scheme :lol:

[Merlin66]

Hmmm
Not much hope then for solar observers (like me) using Skywatcher equipment.....
(Maybe that's why the PST already comes with a "gold" tube - matching accessories?)