What alloy was used in original aluminum trim?

[bergie33]

I am getting quotes on getting some trim parts bright dip anodized and they want to know what alloy was used.  Does anyone here know the answer to that?  They say it effects the temperature of the bath and time dipped.  It would be the rear quarter window trim (vertical b-pillar piece and lower piece) as well as the kidney, all from a '74.

[HBChris]

I doubt that any alloy was used, these aren’t like wheels after all, just plain old pressed aluminum.

[02Les]

Probably an Alum-Magnesium alloy ~ 5000 series.

[joysterm]

3 hours ago, bergie33 said:

I am getting quotes on getting some trim parts bright dip anodized and they want to know what alloy was used.  Does anyone here know the answer to that?  They say it effects the temperature of the bath and time dipped.  It would be the rear quarter window trim (vertical b-pillar piece and lower piece) as well as the kidney, all from a '74.

Have you considered having them plated?

 

 

[bergie33]

Just now, joysterm said:

Have you considered having them plated?

 

 

Plated with what?  I am up for considering all options.  So far, raw aluminum with regular polish and good quality clear coat have both been considered.

[BarrettN]

If you needed some sacrificial sample pieces for them to practice on I have some you can have so they can dial it in on pieces that don't matter. You probably could find others who also have some, possibly closer to you, but if you don't, let me know and I'll ship some practice pieces to you. 

[bergie33]

Thanks for the offer.  Part of their issue is that not knowing the correct alloy will ruin their tank.  I don't think they want sacrificial pieces.

[BarrettN]

Also, maybe ask what it would cost to add more pieces to the batch? I bet there are plenty of people who'd like re-anodized parts, and I suspect the incremental cost will be little compared to what it  costs just the few pieces you need done. Spread the fixed costs across several people and lower your per unit cost for yourself. 

[BarrettN]

1 minute ago, bergie33 said:

Thanks for the offer.  Part of their issue is that not knowing the correct alloy will ruin their tank.  I don't think they want sacrificial pieces.

Mmm - maybe we still need sacrificial parts, but just to send off to a metalurgist if no one here knows the alloy. 

[bergie33]

Just now, BarrettN said:

Mmm - maybe we still need sacrificial parts, but just to send off to a metalurgist if no one here knows the alloy. 

Yes, that is definitely an option.  Thanks for the suggestion. 

[mccusername]

41 minutes ago, BarrettN said:

Mmm - maybe we still need sacrificial parts, but just to send off to a metalurgist if no one here knows the alloy. 

Or find a place that has done old BMW parts before.

 

[joysterm]

1 hour ago, bergie33 said:

Plated with what?  I am up for considering all options.  So far, raw aluminum with regular polish and good quality clear coat have both been considered.

I had the complete belt trim and window and door finishers chrome plated. This was done a few years ago now but it was cheaper to have the trim plated rather  than replace with the OEM anodized bits.  Personally I think the plating looks much better,  but I'm not a purists , so to each his own. At today's prices,  it may be cost prohibitive, but an option for you none the less.

[RogerRamJet77]

You might be able to get a chemical analysis at a local university that has a Scanning Electron Microscope (SEM).  The company I retired from had an SEM that we used for chemical analysis to determine material grade.  I suspect that the aluminum grade used was 1100. See 

Different Grades of Aluminum and Their Applications - Thin Metal Sales

WWW.THINMETALSALES.COM

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Let's discuss the differences between 1100, 6061, and 3003 aluminum and give some other recommendations on what to use for your next project.

 

[Conserv]

King of Trim don’t ask no questions! King of Trim know everything: no fancy alloy in 1970!
 

Grilles, big bumpers, belt-line: they all turned out fabulously. But… you pay a price. Many ‘02 trim items will cost more to bright-dip than to buy new. So… where new is available, think about it.

 

Another high-end “show re-replater” in Massachusetts said they could bright dip. They couldn’t, instead producing a grainy duller finish. The trim on our cars was originally very close to the appearance of chrome. Expensive lesson.

 

Regards,

 

Steve

 

[bergie33]

I agree, it is cheaper to buy the beltline trim than to restore it, at about $600 for for the full set of 10 pieces.  I am specifically looking to get the rear quarter window pieces and two kidneys done.  First quote I got for bright dip anodizing was $250 for the 4 trim pieces and 2 kidneys.  That's definitely worth it as new pieces are about $100 each for the 4 trim pieces and about $250 each for kidneys.