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-   -   Plastic chrome ext. bright-work milky/tarnished (https://forum.a8parts.co.uk/showthread.php?t=11703)

YorkshireBloke 30th May 2016 10:01 PM

Plastic chrome ext. bright-work milky/tarnished
 
Hi,

Finally got to detail the 3.7, first use of clay bar and haven't had a car worth waxing for years!

Thanks to tips on A8 owner's site the job went really well, reviving a neglected exterior and making a start on the interior.

Now I need a tip for reviving the chrome strips on the D2 or if not possible is replacement the only option?? The boot strip is really milky, I rubbed without abrasive cleaner but without any effect.

Thoughts?

Robert

Lee S 31st May 2016 12:01 AM

It's common and nothing you can do about it. Replace the parts with new if you can afford a second mortgage, but even those will go the same way. I think they're anodised aluminium so the tarnishing is permanent. I was going to get mine wrapped with some chrome vinyl... one day :rolleyes:

jza8 31st May 2016 12:35 AM

If the trims are polished or anodised aluminium this might do the trick
http://www.ebay.com/itm/161358861633...%3AMEBIDX%3AIT
Guys on 500E board say it's good havent tried it myself yet.
http://www.500eboard.com/forums/showthread.php?t=8032

edit: I see it's out of stock atm, which is a shame.

ahh here it is http://www.ebay.com/itm/221798363977...84.m1555.l2649

briang9 31st May 2016 12:45 AM

looks like it might be available here too

http://www.ebay.com/itm/221798363977...84.m1555.l2649


http://www.ebay.com/itm/Mercedes-Alu...3D221798363977


might give it a try on the family wagon+++

HPsauce 31st May 2016 08:38 AM

Suffering from the same problem I've been investigating this for years.
As suggested above, buying new (which WILL fail eventually) seems to be the only solution.

I think it's made from polished aluminium with a lacquer coating on top, and water is penetrating between. So any surface treatment is doomed to failure. :tuttut:

moltuae 31st May 2016 08:44 AM

I've researched this a lot lately, and purchased numerous pieces of used aluminium trim to experiment but I haven't got a as far as actually restoring the trim yet.

As I understand it, the problem is that the parts are anodised and the anodised layer has effectively failed, allowing oxidisation to occur beyond this protective surface. Anodising is supposed to prevent the aluminium from oxidisation by giving it an impenetrable 'pre-oxidised' layer. The milky blemishes are the result of unwanted oxidisation within the anodised surface and no amount of polishing or buffing will remove them (unless you polish very hard/abrasively and remove the anodisation layer).

My conclusions so far is that there are 3 options:
  1. Replace with new.
  2. Strip and re-anodise.
  3. Strip the anodised layer and polish.

#1 is likely to be very expensive, if the parts are even available. I haven't looked into this option much though to be honest, so I would be interested if anyone knows the cost and availability of the various 'chrome' parts.

#2 is probably the best option, though I have struggled to find an anodiser who will strip and re-anodise the parts. Most aren't interested and seem to be involved in anodising new parts or anodising on an industrial scale. I still haven't given up on this option though, if anyone knows of anodiser who will do such work? It's also possible to re-anodise the parts yourself, if you're feeling ambitious.

#3 is an option that I originally dismissed but recently started to reconsider. The problem with this method is that the aluminium will quickly re-oxidise without any protective surface, requiring frequently polishing, and clear-coat/lacquers generally don't stick well to highly polished metal surfaces.

I recently came across this stuff however, which claims to be able to adhere to polished metal surfaces:
http://www.frost.co.uk/por15-glisten...art-946ml.html
http://www.por15.com/Glisten-PC-High...oat_ep_75.html

The idea is to remove the existing anodised layer using a caustic soda solution (or Lye, if you're American) like this:
https://www.youtube.com/watch?v=4BxFn0111Bk

... then polish the bare aluminium and use POR15 2K (aka Glisten PC) to protect the finish.

Lee S 31st May 2016 08:50 AM

Hmmmm... Maybe that product is worth a punt. Worth the £20-30 if it does what it says. I have tried every polish, coating, and potion on the market to no avail. I may just order some up... Cheaper than a wrap and certainly a 20th of the price of new trims. Damn Audi... :mad::tuttut:

YorkshireBloke 31st May 2016 10:34 PM

Thanks to all
 
Cheers!

You answers sadly confirmed my first impression based on other cars / motorcycles with chromed plastic or ally trims. Saved me messing about and maybe making worse.

Like the idea of covering in chrome, maybe a few people could club together and help convince a "wrapper" (nothing to do with guns or droogs) to do a batch?? Seems fiddly; got to make it worth someone's while.

I would certainly be interested but have zero contacts in't World Of Wrap.

Robert

David's8 1st June 2016 10:02 PM

'fraid there's no simple answer. I looked at re-anodising with the same result as Mark (Moltuae) in that anodisers are not really interested in small stuff. I treated the piece of trim under the boot lid by completely removing the anodised layer using wet&dry (hard work) and then applying several layers of lacquer. It was OK but is now (2 yrs on) starting to look cr&p again.
Notorius (Sergei) has done a good job on his - no doubt he can explain what he did.

briang9 2nd June 2016 12:54 AM

Quote:

Originally Posted by David's8 (Post 113046)
'fraid there's no simple answer. I looked at re-anodising with the same result as Mark (Moltuae) in that anodisers are not really interested in small stuff. I treated the piece of trim under the boot lid by completely removing the anodised layer using wet&dry (hard work) and then applying several layers of lacquer. It was OK but is now (2 yrs on) starting to look cr&p again.
Notorius (Sergei) has done a good job on his - no doubt he can explain what he did.

think he had then powder coated IIRC:)


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