Author Topic: Anodized Aluminum - Good Result  (Read 865 times)

90077merc

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Anodized Aluminum - Good Result
« on: 03 October 2021, 08:51 PM »
Tonight I attempted my first anodized aluminum trim restoration. I used a dual action polisher with a microfiber cutting disk and cutting compound for about one minute. Although the scratches and deeper marring didn’t come out the cloudiness was polished out.

My question is can the scratches be sanded out or will that remove the anodization layer? I have read the previous posts but they seemed inconclusive on this.
1974 450 SEL

rparker

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Re: Anodized Aluminum - Good Result
« Reply #1 on: 04 October 2021, 05:30 AM »
Good day,
I've also been buying some pieces and trying various methods. The first is a polishing wheel which doesn't work as you need very aggressive polishing rouge to cut through the anodization and once its gone, the aggressive polishing rouge just cuts right through the soft aluminum underneath creating a low spot and its near impossible to get it right along the whole strip.

With regards to your question, I have also tried sanding which does remove the anodization however it creates the same problem as the polishing wheel as the aggressive sand paper that is gritty enough to go through the anodization will make mince meat of the aluminum underneath so the only way is to use a block sanding method, and even with that, the trim isn't 100% reflecting the light straight anymore as some areas have more aluminum taken away than others.

I'm probably at the stage where I will just high gloss hard chrome the trim and be done with it. I've also read that if you do manage to remove the anodized layer that the milkiness returns rather quickly and metal wax has to be reapplied quite religiously which adds to the extra work.

Anyone with better ideas? I haven't tried the oven cleaner method though. I do know that a high chrome finish isn't original but I kind of like the idea of bright chromework.

Cheers.

Ryan.
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90077merc

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Re: Anodized Aluminum - Good Result
« Reply #2 on: 04 October 2021, 04:33 PM »
Perhaps using a fine grit sandpaper rather than the rouge on a wheel would avoid the low spots.

It seems the anodization layer is thin enough to get removed easily, which is not what I’m trying to do.
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rparker

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Re: Anodized Aluminum - Good Result
« Reply #3 on: 04 October 2021, 05:36 PM »
Finer grit is certainly possible and do-able but with the patience of a saint.

From personal experience I can say that the anodization layer is indeed very thin. So any scratches that you can feel with your finger nails is probably gone through the anodized layer already.

Cheers.
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rumb

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Re: Anodized Aluminum - Good Result
« Reply #4 on: 04 October 2021, 06:02 PM »
This is a deep rabbit hole to go down. I took a big batch to local plating shop to have the bright dip anodize removed. The first batch they over etched. Most of the other pieces came out ok. I have heard of oven cleaner and tried it once to no avail.  The anodize layer is very hard. In order to remove all the scratches the entire piece must be sanded somehow.  I have used 2" discs of 200, 400, 600, 800, 1000, 2000 grit and that is still very time consuming and hard to get all the imperfections out.  Next I have 8" buffing wheels and a good buffing machine, which is certainly required, and that is hard labor. It take a long time and various strength compounds. You go thru and get to fine polish and then see more scratches that send you back several steps. I probably have spent 8 hours on each piece I have done.

After all the polishing is done then they must be sent out for bright dip "anodizing" to put the protective layer back on.

What size wheel are you using?  I use 2 doubled up 8" ones at 1800-2000 rpm. I would even consider a 10" buffing wheel.

what rouge do you have? I have tried several from https://caswellplating.com/buffing-polishing.html
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rparker

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Re: Anodized Aluminum - Good Result
« Reply #5 on: 04 October 2021, 07:17 PM »
Rump,
I'm actually using a lower quality Daewoo bench polisher, 6 inch, 1800rpm however it does vary depending on the diameter of the mop. Some mops I've worn down to 3-4" which would mean that the speed is much slower across the work area. Anyway I've shelved the idea as the variation in material hardness between the anodized and non-anodized is too great and as a result the once the anodized layer is gone, the rouge and wheel will eat into the aluminum almost immediately, creating imperfections very quickly. Worst is sometimes the anodization comes off in patches creating high and low spots that will not reflect light crisply. I used mainly Dialux Grey Rouge (for Stainless and Platinum). I did use less aggressive rouge but it wasn't cutting the anodized layer and was introducing way too much heat onto the piece (which weakens the aluminum even more).

Totally agree with the seeing more scratches and having to go back a few steps, especially if you have already worked through half the piece's anodization and the finished side gets a new ding. It really takes too much time and care for the result. When sending out for anodization it must be specified "bright dip" or the piece comes back in a matt finish. And personally to me, even with the "bright dip", the finish isn't mirror finish, it is still satin finish like (which is factory spec for Mercedes). I actually prefer my brightwork very bright.

Anyway, to cut the story short I've consulted with a few classic car enthusiasts and the vast majority said just get it chromed plated. One younger gentleman however said technology has progressed, all you need to do it wrap the piece in vinyl chrome wrap and it'll last for years, nobody will know. This sounds appealing to me so I've ordered mirror chrome vinyl wrap which I will experiment on.

Cheers.

Ryan
 
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UTn_boy

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Re: Anodized Aluminum - Good Result
« Reply #6 on: 05 October 2021, 12:38 PM »
The anodization is applied by submerging the part in a medium of dilute hydrochloric acid or muriatic acid.  In the medium is placed and anode and a cathode.  One is positively charged, and the other negative.  In order to remove the anodization, the process is reversed by changing the polarity of the anode and cathode.  The medium has to be temperature controlled based upon the size of the piece being worked with, and the voltage to the anode and cathode must also be controlled according to temperature and the size of the piece.  It's not exactly an easy process.   Lest we forget about the acids we're working with.  Ventilation will be needed, as well as a controlled DC power supply. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
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rparker

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Re: Anodized Aluminum - Good Result
« Reply #7 on: 05 October 2021, 07:26 PM »
UTn_boy,
Good knowledge to know. Thanks for that. I'm thinking of buying a home chroming kit sometime in the future as its seems the classic car bug that bitten me quite early in life (i'm 40) and find that I'm very particular with brightwork and finish. Would you happen to know if it is something that is do-able in a home garage setting? I've watched a few YouTube videos and it looks quite easy but I'm still unconvinced.

Cheers.

Ryan
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UTn_boy

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Re: Anodized Aluminum - Good Result
« Reply #8 on: 06 October 2021, 12:31 PM »
I suppose it's doable in a home garage provided you have all of the correct equipment and some understanding of chemistry under your belt.  But applying chrome plating to aluminum is not a good idea.  They do no bond well, and the chrome will cause two problems.   

1) It'll start peeling off in short order
2) It'll thicken the trim pieces causing fitment issues. 

There are places that still do bright dip anodization.  It's costly, but worth it.  Last year I had all of the aluminum re-anodized off of a 1960 Ponton, a 190b.  It cost around $4,000-$5,000. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex

rparker

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Re: Anodized Aluminum - Good Result
« Reply #9 on: 06 October 2021, 04:17 PM »
UTn_boy,
Right on, once again, great advice! Thanks for the knowledge. Anyway, I'm waiting for the 3M gloss wrap which I've seen in person and looks quite convincing, just the fitment might be an issue as you've mentioned.

I'd just like to confirm with you that the bright dip anodization is a satin like finish like the day it came off the showroom floor? This is what I've been told and it is in conflict with what I've seen with many W111/112 restorations where it looks like all the brightwork is indeed mirror-like where I know the trim (e.g. window frames) should be anodized aluminum.

Thanks.

Ryan
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UTn_boy

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Re: Anodized Aluminum - Good Result
« Reply #10 on: 07 October 2021, 11:48 AM »
I don't know who told you that the aluminum trim was supposed to have a satin look/finish to it.  That's absolutely incorrect.  When new, these pieces looked almost like a piece of chrome.  If these people still say otherwise, then I'll be more than happy to share some pictures of some new old stock pieces. 

W111 and W112 coupe` and cabriolet cars have chromium plated brass around the windows.  Only the trim that surrounds the top and sides of the windshield was anodized aluminum.  After 1968 when the W111 280 models came about, the full face wheel embellishers were chrome plated steel (but only for the first 300-400 280 models), but became polished stainless steel until production stop. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex

rparker

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Re: Anodized Aluminum - Good Result
« Reply #11 on: 07 October 2021, 04:44 PM »
I base this on some posts I've read previous unfortunately can't remember where at the moment. I also have my brother's W126 which has been sitting in a basement almost all its life, barely driven that is almost a time capsule. The trim is immaculate and the finish is indeed a fine satin (not from going milky, because it is consistent throughout the trim and on all trim pieces) , but having said that it is very near mirror finish, but just not quite there.

Thank you for the information on the W111/112 coupes, again good knowledge to know as these become so incredibly priced lately.

You've spent a lot of time on me, and I appreciate that sincerely. But some photos to illustrate your point would be very much appreciated. I'd also try to look up the old posts that have led me to the conclusion to show them.

Cheers.

Ryan
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90077merc

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Re: Anodized Aluminum - Good Result
« Reply #12 on: 07 October 2021, 09:10 PM »
I feel like we need an Mercedes anodized aluminum wikipedia.
1974 450 SEL

rparker

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Re: Anodized Aluminum - Good Result
« Reply #13 on: 08 October 2021, 02:24 AM »
90077merc,
Agree, there is certainly the proper way to do it, which is basically to strip the anodized away chemically and have it re-anodized and done to a very particular specification in "bright anodized", or however the workshop terms it, it may come out less than optimal and you'll have to do it all over again (and bare the costs). That is assuming the trim is structurally near perfect. Now that a more experienced enthusiast has recommended against chrome plating on aluminum, that's out of the window.

Anyway, my car has trim that is in poor condition, little dings here and there, pitting from age etc. My plan forward (which I will share on this thread) is to treat the test piece (its the little chrome trim above the front light) which has a ding in it, can be hammered out, but will never be straight again. Am going to apply filler, sand it down and wrap 3M 1080 gloss mirror chrome on it. I'll share the (1) Before, (2) After and (3) After on the car so we can learn from this. The gentleman that shared this with me has a Volvo 122 sedan that isn't of any particular value but did indeed stand out for its brightwork. Even the bumpers which had previously rusted through was treated with fiberglass filler and the said wrap, really couldn't tell the difference looking at it unless you look at the back of the chrome bumpers.

I look forward to it.

Cheers.

Ryan
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UTn_boy

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Re: Anodized Aluminum - Good Result
« Reply #14 on: 08 October 2021, 01:59 PM »
I base this on some posts I've read previous unfortunately can't remember where at the moment. I also have my brother's W126 which has been sitting in a basement almost all its life, barely driven that is almost a time capsule. The trim is immaculate and the finish is indeed a fine satin (not from going milky, because it is consistent throughout the trim and on all trim pieces) , but having said that it is very near mirror finish, but just not quite there.

Thank you for the information on the W111/112 coupes, again good knowledge to know as these become so incredibly priced lately.

You've spent a lot of time on me, and I appreciate that sincerely. But some photos to illustrate your point would be very much appreciated. I'd also try to look up the old posts that have led me to the conclusion to show them.
Cheers.I
Ryan

We can't use a 30+ year old car for comparison to how the trim looked when new.  The trim will loose luster over the years regardless of mileage.  It's more so a matter of time rather than miles or having been outside or not.  Factors that also influence this range from the trim's exposure to acid rain, salty air, damp basements/climates, what kind of soap is used to wash the car with, how abrasive the sponge or cleaning pad is, how abrasive the drying towel is,, etc.  You see where I'm going. 

In the pictures below I've displayed 4 pieces.  The top piece is a new old stock trunk handle for a W126.  The second piece down from the top is a lower trim piece from the rear glass from a W116 that has been clouded from being out in the elements 40+ years.  The third piece down from the top is a new old stock flag staff holder that is actual chromium plated, and is the piece being used for comparison.  The last piece, the piece on the bottom, is a new old stock W116 trim piece that goes around one of the door windows.   

In the last picture I show a close up of the new old stock anodized aluminum and an actual chromium plated piece. 

As you can see, the aluminum trim looks almost like a piece of chrome.  I hope this rids any and all ideals about the pieces having been satin or dull when new. 
« Last Edit: 08 October 2021, 11:29 PM by UTn_boy »
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex