Restoring Aluminum Trim

CharlesJ

CharlesJ

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Looking to do a full restoration of all the aluminum trim (interior and exterior) on my coupe and looking for the best solution to do so at this scale. I read through a wealth of prior threads on this topic that seem to lean more towards DIY polishing and clear coat, or polish and ceramic coat, but my preference would be towards OEM style Bright Dip anodizing. The problem is, I cannot find much detail on this, or vendors that do it. With that, have a few questions

  1. Are there vendors out there that will do the restoration and original style anodized finish that people have used? Any idea what the cost is?
  2. For polish/coat solution, I know some people have mentioned Speedway as a good source. With them, what is the coating and how well does it hold up versus anodizing? Are there others that do this?
  3. Also, the two little pieces on the shifter surround that hold the window buttons looks to be a different finish - does anyone know what that is?
  4. Any other good ideas for having this restored?
Thanks
 
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not sure of anybody who does polished anodized finishes ... probably out there

I can speak to the quality of what Speedway does - anodic finish stripped, metal polished and finished with a ceramic coating. the cost for all of the belt trim is probably about 1000 bucks or so. mine was done about 5 or 6 years ago and the cost was about 700 bucks.

the two strips on the shifter are also anodized, just not polished. haven't had these restored. perhaps @OCCoupe can speak to this.
 
Re anodizing of the interior bits is technically doable, the 2 plates by the shifter, the dash trim. They will come out nice if you take care of the sanding/polishing.

The outside parts often yield bad results when re anodized, as the old parts being exposed to the elements often have pit corrosion on them, going often deeper then what you sand off in preparation. Then upon anodizing, stuff that's inside those remaining pits/pores oozes out and contaminates the shiny surface with dull spots, showing usually as 1 or 2 mm grayish discs.
It also impossible to spot the pit corrosion by eye while polishing. The osolution is to check with these 2 stage Crack detection dye's; after you sand and polish, you spray it with a red penetrating die. If there are any pits/cracks, it'll pull in. Then you wipe clean, and spray with a white chalk that pulls the red ink out. If you have no red ink showing, then re-anodising should give you beautiful results.
More here:
grassrootsmotorsports.com

Testing for Cracks at Home with DIY Dye Penetrants

There is an inexpensive, at-home way to perform a DIY crack and flaw inspection on many of your car’s components. The method is called visible dye penetrant testing.
grassrootsmotorsports.com grassrootsmotorsports.com

However shops often don't want to re-anodise, as they all learned that most exterior stuff that is brought in by DIY people is ill prepared, and then the customer complains when they come and pick it up. Should you go this route, they will likely only want to coat your stuff if you agree with them beforehand that any result will be your risk.

I've professionally anodized a lot , but never e9 trim. That is why I have bought one busted trim piece some time ago. It'll be the guinea pig ...
 
eriknetherlands said:
Re anodizing of the interior bits is technically doable, the 2 plates by the shifter, the dash trim. They will come out nice if you take care of the sanding/polishing.

The outside parts often yield bad results when re anodized, as the old parts being exposed to the elements often have pit corrosion on them, going often deeper then what you sand off in preparation. Then upon anodizing, stuff that's inside those remaining pits/pores oozes out and contaminates the shiny surface with dull spots, showing usually as 1 or 2 mm grayish discs.
It also impossible to spot the pit corrosion by eye while polishing. The osolution is to check with these 2 stage Crack detection dye's; after you sand and polish, you spray it with a red penetrating die. If there are any pits/cracks, it'll pull in. Then you wipe clean, and spray with a white chalk that pulls the red ink out. If you have no red ink showing, then re-anodising should give you beautiful results.
More here:
grassrootsmotorsports.com

Testing for Cracks at Home with DIY Dye Penetrants

There is an inexpensive, at-home way to perform a DIY crack and flaw inspection on many of your car’s components. The method is called visible dye penetrant testing.
grassrootsmotorsports.com grassrootsmotorsports.com

However shops often don't want to re-anodise, as they all learned that most exterior stuff that is brought in by DIY people is ill prepared, and then the customer complains when they come and pick it up. Should you go this route, they will likely only want to coat your stuff if you agree with them beforehand that any result will be your risk.

I've professionally anodized a lot , but never e9 trim. That is why I have bought one busted trim piece some time ago. It'll be the guinea pig ...
Click to expand...
That’s great insight. I’ve wondered a lot why I don’t see more people go this route or more shops that do it, so very helpful. I do see one main specialty shop for this that does a 9 stage process of restoring trim with anodizing, but I have heard the price they charge is on par with painting a car - King of Trim
 
We had all of our new BMW supplied beltline trim chrome plated to match the rest of the plating on our car with great results
53717439497_96d10ef3e4_o.jpg
 
CharlesJ said:
Looking to do a full restoration of all the aluminum trim (interior and exterior) on my coupe and looking for the best solution to do so at this scale. I read through a wealth of prior threads on this topic that seem to lean more towards DIY polishing and clear coat, or polish and ceramic coat, but my preference would be towards OEM style Bright Dip anodizing. The problem is, I cannot find much detail on this, or vendors that do it. With that, have a few questions

  1. Are there vendors out there that will do the restoration and original style anodized finish that people have used? Any idea what the cost is?
  2. For polish/coat solution, I know some people have mentioned Speedway as a good source. With them, what is the coating and how well does it hold up versus anodizing? Are there others that do this?
  3. Also, the two little pieces on the shifter surround that hold the window buttons looks to be a different finish - does anyone know what that is?
  4. Any other good ideas for having this restored?
Thanks
Click to expand...
Charles,
Re-brightdipping in my experience does not work. If you had new / virgin aluminum with perfect process control (as the OEM suppliers have) then it would work. Unfortunately with 50 years of pitting, rock chips, corrosion and electrolysis. The issue is the impurities and pitting. You can polish the trim to your visual perfection but when you introduce it to the bright dipping process (elevated temperature) after the coating goes on, all of the outgassing and impurities come to the surface. The results are lots of splotchiness and uneven surfaces. I would suggest simply polishing your old trim and then Cerikoting it with their high gloss clear coat. Good luck.
 
when i got my coupe - 13 or so years ago, i did notice that the rear belt trim scratched quite easily. i learned that the rear belt trims had been chromed by the PO. while doing something to the car (don't remember what i was doing), i put a piece of masking tape on the rear belt trim and it pulled bits of the chrome off of the trim. i ended up sending them to speedway - they dipped and removed the chrome ... polished and ceramic coated them.
 
CharlesJ said:
That’s interesting. I’ve read a little about chrome plating the aluminum - any downside other than not OEM correct?
Click to expand...
I chrome plated my old belt line professionally ten years ago. After about 5 years the chrome started to peel off. This is the result on all the different pieces.
 

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True chrome plating, which is a three stage process (copper plating, then nickel plating and finally chrome plating) would never give you results like that. We have items chromed by the same company using the correct process from twenty years ago that still looks brand new.
 
eb88 said:
We had all of our new BMW supplied beltline trim chrome plated to match the rest of the plating on our car with great resultsView attachment 183857
Click to expand...
Part looks mighty nice.

Curious; BMW sold trim parts that were I'll fitting, especially the rear L and R, in the corner where the wrap around the trunk.
When did you buy your parts? Did you test fit yours? How did they line up?
 
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