107 Euro Headlight Reflectors Refinished Very Well - WITH TAPE!!! (long)
 

Before you completely dismiss the title as an idiotic idea, please read on. Although it is possible to get new 107 Euro headlights (very expensive), it might be impossible to get them for older models and the technique described below may be of some use if you are "handy".

I've purchased two sets of Euro headlight assemblies, the second set inexpensively, in need of refinishing (the second set is for my next 107, which I don't even own yet). Both sets had bad reflector bowls. These are coated with vapor-deposited aluminum, and they do wear and corrode from underneath. Ordinary chrome platers can't (apparently) replate them; I had my first set refinished in silver plate at horrendous expense (which all in all make the set cost about as much as a new set), and the results were still not perfect. In any event, chrome isn't as reflective as aluminum (much better) or silver (even better still) anyway.

As you probably know, the Euro bowls are just not available through MBUSA and arent cheap even if you can get them at all. So, what do you do? Paint has proven to be absolutely worthless. Technically speaking, Euros aren't legal in the US, etc, read the following and proceed at your own risk, and so on. It is imporant that all steps, particularly the last, are followed. If you intend to do something like what is described below, I'd advise you to practice on a junk reflector bowl or a piece of junk, concave curved metal before proceeding.

I bought some aluminum tape at Harbor Freight, at 3 rolls of 2" tape for about $8.00 (for some reason, they aren't sold separately). This tape is also available on eBay, in 1,2,3, or 4" sizes. I would recommend the 1" or 2" size, for reasons explained later. This tape, I beleive, is used in HVAC ducting; it is likely that the adhesive can survive temperature extremes and my testing shows that it does. It seems to be of good quality and is advertized as being 2 mils thick. I also bought a few sheets of 320 and 400 wetordry and an inexpensive drill-mounted buffing wheel with "white" buffing compound.

Surface/Reassembly Preparation

This is going to sound extreme, but I sanded all corroded areas of the bowls with 320 wetordri sandpaper, until smooth. It is not required or recommended to remove the existing aluminum if it is not seriously corroded underneath. You will of course have to disassemble the bowl from the headlight assembly in order to do this; this procedure is not discussed here. I should note that both of mine that have been refurbished had TERRIBLE gaskets that contributed to their deterioration. Obviously, you must replace the front glass l to headlight assembly seal if your bowls have corroded. All of my adjusters were rusty junk and I had to essentially make replacements out of new hardware. I used a "thumbscrew", ground down and tapped through the "thumb" part, to replace the actual adjuster ends, for example.

Taping Technique

Here, in a nutshell, is the problem; you will be applying a not very stretchable, flat material on the surface of a rather deep paraboloid. Even if you had a sheet cut perfectly to the size of the bowl, you would never be able to install it. So, my solution was to apply the tape in slightly overlapping (1/32" max overlap) strips, 2" in the center and then about 1" on top and bottom. I later modified this to using 4 pieces of approximately 1" for the main part of the bowl. If you bought 4" tape, don't try to use it as is because wrinkling will become extreme due to the curvature of the bowls. Make "models" out of ordinary paper and cut the tape to fit. This is especially important for the top and bottom pieces. It is ok, and in fact a good idea, to wrap around the edges of the bowl. The centerline of the reflector makes for a good seam, because it is behind the light shield support anyway. Work slowly; if you make a mistake, you have a lot of tape left and it isn't very expensive. Burnish your results with a cloth and press hard, leaving absolutely no seams loose. Try to minimize wrinkles and avoid or poke a hole in air bubbles (don't freak out about wrinkles, because in the next step the vast majority of them will be eliminated). Keep overlaps straight with one another. Trim the holes for the light shields and driving light if so equipped with a utility blade or hobby knife.

Sanding

Your results will be "okay", but not really as reflective as they could be, and then there are the "wrinkles". I would NOT use them in this condition. The adhesive is somewhat lumpy, and the surface of the aluminum isn't really polished anyway. The following technique will yield amazing results that through my A/B comparison to my silvered headlight bowls are very, very close to as good as new, and possibly even better.

Sand the aluminum you've put down on the bowls with 320 wet or dry under the faucet in a sink until all "high spots" from the underlying adhesive and imprefections in the aluminum (from wrinkles, among other things) are nearly gone. You should wind up with an even looking bowl, brushed in apperarance. Many of the wrinkles will have disappeared. Now, using the drill mounted buffer (observe safety precautions, use mask, glasses, etc, don't let parts fly), buff the interior of the bowls. The results will be quite surprising. Nearly all of the tape wrinkles will be eliminated; it will be extremely difficult to see remaining imperfections through the front lens of the assembly after installation. The seams will perhaps still be visible but if you kept them straight, they will not look bad or abnormal. The bottom line, is that your results should look something like what you see when you look up at the light while in a dentist's chair! You should be able to see yourself quite clearly in the reflection. I'd take a picture - but it's very difficult to do this!

Before reassembly, you must remove every trace of grease from the buffing compound, fingerprints, etc from the aluminum. I used brake cleaner on a flannel cloth (don't scratch the tape, the aluminum is soft), and cleaned until all of the black was gone. This is important because I think that the grease will darken the aluminum eventually when the assembly heats up. It might not be a bad idea, however, to go over the bowl in a final pass with very thin coat of car wax.

After reassembly, I've operated these for 10 hours (under safe conditions so that there was no chance of a fire) from an old +12V PC power supply, and the tape did not exhibit any lifting or curling problems. Certainly, I reached close to the max temperature that these will see (accounting for the 1.8 volt difference between the PC power supply and a car's electrical system). This is not a complete or thorough test, but I'm confident that if kept dry with new front gaskets, this will last for quite some time, and the bowls are completely re-restorable by me (I have enough tape left to do this every few years if I have to for about the next 40 years).

Note that the side reflectors for the marker/turn lights can be redone using essentially the same techniques.

The results were so good that had I thought of this in the first place, I would not have spent the several hundred dollars to resilver the first set, and I'm very, very picky about what I find acceptable for my car.

You amaze me!
 

I find your posts incredibly informative; I especially like your outside the box approach to fixes.

I'm sure others here appreciate the time you spend posting also..

Thanks,
Kevin

I would love to see some pics.

I will try to put some up in a few days. Close-ups of the adjusters and substituted rubber anti-vibration parts (which disintegrate upon disassembly) would probably also be helpful.

Here are pictures. Actually the reflector turned out even better than shown, after a final buffing just before installation (this should be the last, not the first, thing that you should do). I also added new sockets for dual-filament side lamps, and there is detail on homemade adjusters (using 6-32 screw, strong spring, washers, and locknut, with a thumbscrew ground down and tapped as the adjuster part). The light pattern is shown; in terms of brightness, it seems close to my "daily" car but not quite as bright as my silverplated euros installed on my 560sl.

These were "junk", so they took a lot of work; one was vacuum based (shot); I had to make an arm for it like the other non-vacuum based light.

Looks like I can do the same thing with my fog lamps on my 560 SEC!!!

Thanks
Jack
1980 450 SL
1985 380 SL
1989 560 SEC

Great idea and thread, Strife. This one will help a lot of members. Many thanks :).

Wow.

I've used the aluminum tape to brighten up taillight reflectors, but I never thought you could sand and buff it enough to make the headlights usable.

Great idea, I've got a couple of sets of dull reflectors and looks like a trip to Harbor Fright is in order....

Thanks for a great idea!

Jim

The quality of sanding and buffing will make a BIG difference in your results. I worried that people would just put the tape on and go with it, which I think would give very dim, diffuse, and downright dangerous results.

Great idea. I've got a couple a candidate reflectors on which I could try it. I'd like to see some picks of the finished product.

Mine have been in the car for about 1.5 years, but I think the three rolls of Harbor Freight tape were about 10 bucks and enough to screw up 30 times over, and this is a rare case where you can screw up over and over with nothing lost but your time. Assuming that you get the seams good and minimal bubbles/wrinkles, the sanding (with 320 or 400 wetordri, damp/wet) and buffing with the white compound you can get at HF or home depot/lowes is where the real results are. They are on the gold colored car in my gallery.

You can get alot lore more shine and a do a lot less work with a quality tape from Tyco or Nashua. I use some at work for HVAC ducting that's so thin it actually stretches slightly to conform to curves and has a mirror finish right off the roll; unfortunately, it's got "Nashua" printed on the shiney side.

Once I get back to work I'll see if that's removeable and get some details on the tape.

I got a set of euro's for my car from Germany, and the left (driver, RH drive) reflector is showing some brown. They're still much, much brighter than the old DOT bulbs, but still...

I should mention that I eventually DID get a spare set refinished properly, vacuum-plated and overcoated by a place that does custom work for Detroit. It wasn't cheap and _I_ had to do the prep work on it, but they are better than new and have modern, UV-hardened coatings that CAN survive very light cleaning. I've been trying to work out a way to do business with them on a regular basis - I have a spare set and I might be able to send out finished reflector bowls with a very, very high "core" charge.

My taped reflectors, on the other hand, are still very, very good after about 3 years.

This looks like a very usable fix for very old Citroen headlights which were cast metal where the inside was chromed. Once the chrome is gone, it's impossible to re-chrome old pot metal. But this would definitely workl, with some care.
GREAT idea.

I have now inherited a 380SL with virtually no rust but potentially some other problems, and as soon as I get space, I'll tell you more. No time to work it now: 7 degrees out and 4" of snow coming!:eek::eek::eek::eek::eek::eek:

I need to do this on my passenger euro. The last time I did it I just used cheap ace hardware HVAC tape and it's FULL of wrinkles.

I want to try this... :D