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

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:

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

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+++

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:

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.

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:

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

'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:)

HERE is the thread for what he did +++

You could always get the trim chrome wrapped

Sounds like a good option. Any photos of this done ?

May be an option here, ive just spent the last couple of hours cleaning up the rear bumper chrome trim.
Gave it a rub down with 1200 grit wet n dry, followed by a liberal application of Alumagic paste.
A quick buff down with microfibre cloth seems to have cleaned it up.
How long it lasts is anyones guess

Seems I remember boiling in simple H2O will cause a surface layer of aluminum oxide to form - a very durable substance. Only trouble is it's a matte gray finish AFAIK.

Yes in the US I bought some "Air Conditioner Coil Cleaner" liquid which turns out is simply a strong sodium hydroxide (lye) and water solution. It foamed up madly and removed 40 years' worth of dirt from my evaporator and condenser coils on the home HVAC, and shined up my dear departed Granma's espresso (moka) pot. Can't one buy lye drain opener in the UK?

Haven't experimented much with it as it requires full protective gear which is HOT and cumbersome in the Tennessee heat... and I actually heed warnings to the point of buying a $90 respirator w/ organic vapor filter for this job. Along with industrial rubber sleeve gloves, face shield, etc.. Having worked on an ambulance here in "Hey man, hold my beer and watch this!" country, I've seen some things...

:ROFL:

Yes you can get Sodium Hydroxide drain cleaner here. some have recommended it for cleaning the drains in the scuttle (probably called something different in USA ;) ) but I am not sure I want it near paintwork even under the bonnet(hood) as is (obviously) caustic. :eek::eek: By the way, how did the coffee taste? :p

Aluminium and Caustic soda is a VERY VERY BAD IDEA! :eek: https://www.youtube.com/watch?v=FdRrZH3M5O0

But look at how CLEAN it is!! :ROFL:

That could be your body work.........

Coffee was fine; in fact the reason I researched how to treat the "raw" aluminum (aluminium* to you guys) was prevent any metallic taste - before I cleaned the 100-year-old pot, which had a layer of mineral buildup in the bottom (remember a moka pot boils dry each time)nothing would (chemicallly) touch.

I don't know what the US equivalent of "scuttle" is ("Sump?) however I do know what the word means, but I know VWs and Audis have a definite problem with their (scuttle) drainage!

*My wife is from Germany, moved to the US when she was 13; when I met her 20-odd years ago, she could not say the Al word either way; especially funny since she has two Masters' degrees - and one is biology! (A good old science joke here is to have someone say "aluminum" ten times as though it were a tongue-twister, then ask them what a tin can is made of)...

You are correct, sir; as I said...
In any case I have misunderstood the question - OP is talking about the plastic strips, and I was thinking of the removable window trim that is worn-looking on so many of our cars. I have always wondered how they chrome-plate plastic (assuming they do). There was an episode of "How It's Made" (Canadian TV series) which detailed the process IIRC.

I had a little experiment today and now think there are two problems, one of which is sort of fixable.

I've seen comments about people polishing the trim with just WD40 and have tried that myself. It works in some areas but not others.

Thinking about it, where it works the damage must be mainly on the surface, so I tried a test area with a thin layer of lacquer topcoat, having cleaned it thoroughly first and it worked quite well. It's the small shiny area in front of the mirror pivot in the first picture below. That trim on the drivers door is only slightly milky.

I think a fair bit of the trim on my car is just affected by surface degradation, so I plan to treat all of it, in stages, with clear lacquer.
I know some bits (notably the trim under my offside headlight) will not be improved much by that, but I'll give it all a go eventually, I don't have enough lacquer on hand at present to do anything other than small tests. :tuttut:
The second picture shows that headlight trim, it was all milky but I treated the centre and right areas. The right improved a lot but the centre highlighted the deeper damage that is shown by the obvious milky streaks.

Just to share my experience.

Autosol Chrome Polish.
This stuff is brilliant and done miracles for me. Yes it requires around 40min to get just one rear triangle chrome trim done, but after that chrome looks nearly new.

I will look for before and after pics.

Can't find the pics, but found a short video of almost finished trim.
It was nearly white and really bad looking.
You just have to keep polishing and polishing and polishing even if it looks like it doesn't work - it works, just needs time.

Agreed ^ There are two versions of Autosol too - a coarse version in a tube, and a fine version in a tin. I use a mini polishing pad designed for headlights in my battery drill. One pad for the coarse to take the discolouration out, and then another pad with the fine to make it shiny. It does take a long time and its never quite perfect but its better than nothing. Mask off the paintwork beforehand if you're using that method though!

Wrapping it satin black is better still ;)

Well, I've just realised that Autosol I've used is not actually a polish but a liquid chrome cleaner. Whatever it is it did the job very well.
Just microfibre cloth for me +++

https://images-na.ssl-images-amazon....L._SL1500_.jpg

Interesting. That's different to both the types I have! I might have to seek that one out as well +++

It works very well on aluminium and brushed aluminium parts as well +++

Cheers Marcin - that would make sense, given the other (more common) Autosol is essentially a metal abrasive so I'd be concerned about it leaving the chrome more exposed than before starting... +++

Has anybody considered getting all of these pieces chrome plated?

That should give a long term effective finish

I did look into chrome plating a few years ago. As I understand it, it's more complicated to plate aluminium, partly because it has to be plated with something like copper and/or nickel first I think. It's been a while since I researched it though so I'd be interested to know what you find.

One problem with most restoration methods is that the trim must be removed first, some parts of which are difficult to remove/refit without damage I believe.

After considering various methods I was leaning towards polishing (ie mechanically removing the anodised layer then polishing/buffing to a mirror finish) which should be possible to do in-situ (with care). The problem then is how to protect the polished aluminium from oxidisation because conventional lacquers won't adhere properly to a highly polished surface. Two solutions I have considered to that is to either go for a duller (and arguably more natural aluminium-like) appearance, or use this stuff, which they claim is very hard-wearing and can adhere to polished metal surfaces.

On a recent visit to The Carding Shed (at our Annual Meet), I asked Ian Kellet (of IK Classics), who gave us a tour of their restoration workshops, what they would do to restore anodised aluminium. He agreed it was problematic to restore and said that they use a company called Metal Magic who simply powder-coat the trim for them. He said that even close-up, some of their powder-coated finishes are difficult to tell apart from genuine chromed pieces.

The trims under the headlamps are my main concern as they are pretty tired.
The bumper comes off easily enough to access them

I need to think on this!

:)

+1 for the Autosol Liquid Chrome Cleaner.

One of my rear quarter window trims looked like it had been involved in some kind of acidic dogging incident. It's took about an hour of rubbing (fnar!) but it's definitely faded the effect.

Pics?+++