How to get rid of the yellowed headlights

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lunes
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Post by lunes »

well, another way to do it, strangely...

I have a spray bottle of simple green (that I use for EVERYTHING) and it took most of the yellow off, and then I grabbed a pack of 1500 grit paper (from Walmart for 2.50) and some duplicolor clear coat (also Walmart for like 3.50) and I didn't have a spray bottle of water, so I wet sanded with simple green... about 5 minutes of polishing and the lens was clear, wiped it with rubbing alcohol and then coated the lenses 3 times with thin coats of clear, will upload the pics next time I go somewhere with broadband (probably Thursday morning) I had polished the first pair on my first 90 legacy, and the yellow started to come back in about 3 1/2 months (with no clear coat) I coated BOTH my sets (since I have 2 cars) and my one spare passenger headlight as a test... this even took out some minor scratches in the headlight lenses from shopping cart/road debris damage. EXCELLENT IDEA.

AND! FYI. do NOT let simple green touch your paint. it will remove wax. no kidding. will remove car wax just spray on and wipe off and your coat of wax is gone. (trust me, I washed a car with simple green once, and it took a week old coat of Turtle wax right off without any work.
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Post by evolutionmovement »

The lenses are polycarbonate. You want a UV blocking clear coat as the UV causes the yellowing. If you feel real adventurous, you could do the inside of the lens, too, by heating up the adhesive around it with a heat gun and pulling them off to get at them since the headlights also put out some UV, though the yellowing is minimal from the few I've cracked open. The headlights are originally coated with a UV inhibitor (and probably a scratch reducing coating) which is why it takes a while for them to get yellow initially, but very little time afterwards.
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Post by CoreyMN »

I actually had pretty good results using a Mr. Clean Magic Eraser. I just wet it a little then scrubbed the lenses while they were on the car. I think that it would still be a good idea to clear coat them, but I haven't yet.
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Post by evolutionmovement »

They will turn yellow in weeks if left outside. The polycarbonate comes with a UV inhibitor that keeps them clear for a few years, once that's gone there's nothing to slow the yellowing. The headlights themselves also emit UV.

I'm lazily finishing this headlight project. I just need to weld the new clear covers to replace the original lenses. Still shopping for a good UV-inhibitor.
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Headlights don't emit enough UV to yellow

Post by polychrome »

The headlights do *not* emit enough UV light to yellow the polycarbonate. Incandescent lamp filaments have almost no emission in that range. The soft quartz capsule for the filament doesn't pass UV. The plasic coating on the relector at the rear of the assembly doesn't pass UV.

The underlying reason why your headlights are yellowing rapidly is because the UV stabilizer built into the plastic (its not a coating) is slowly used up and eventually exhausted. Adding a UV barrier layer helps, but the UV stabilizer is part of the overall polymer stabilization, so you will still see some accelerated aging.

If your headlights are yellow on the inside, its probably the polycarbonate cross-linking due to the heat. UV light and heat aren't the only agents promoting cross linking (yellowing). There are also bromine compounds added to the polycarbonate to make it self extinguishing if it catches fire instead of highly flammable. These compounds tend to accelerate plastic aging.

I'm skeptical that DupliColor spray urethane will hold up for rmore than 2 or 3 years. One part urethanes adhere poorly, are softer, and age far more quickly than 2 part urethanes. They are cheaper, less stinky, and have a longer shelf life. The professional who recommended a clear coat was almost certainly thinking of a 2 part product. To the professionals Duplicolor products are "spray lacquer" - a nuisance that has to be removed so it doesn't peel up and ruin a good paint job.

I've used the 3M plastic cleaner and 3M plastic polish every 2 or 3 years since '01 on our two '92 Legacy wagons. The 3M products are both fine grit rubbing compounds without wax. I've repolished to remove environmental abrasion (road sand) not yellowing. Wet sanding starting with 1200 and then 2000 and then polishing might have been a little quicker for the first go-around.
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Post by evolutionmovement »

I read about the UV lamp aging the polycarbonate from a couple sources while searching for a UV blocker. I didn't observe the internal yellowing personally. The sources I found offer a more scratch resistant polycarbonate for wear applications. What is the process to make them scratch resistant? Is it a coating or an additive? Do you know what they use to block UV on external applications of bullet resistant glass (the polycarbonate, of course, not the laminated glass).

Also, since you seem to have a good knowledge of this stuff, I've read properly UV stabilized acrylic can resist yellowing indefinitely if kept properly clean. Is this marketing hype and, if not, how do aquariums maintain the clarity of their tanks, and why don't these inhibitors work as well with polycarbonate?
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Polymer chemistry is a little complex for this forum....

Post by polychrome »

For the questions -
how do they make them scratch resistant - polycarbonate is a classification of a polymer dominated by linked carbonate groups. The bulk material properties can be altered by changing what other groups are used and how and how much cross linking between chains is done. As with metallurgy there are no total freebies. Harder is more brittle, etc. You can spend more for a more constructed polymer and beat the trade-off to some extent. An example or a superior polycarbonate variant is Lexan.

Can they really make polycarbonate that never yellows in full sun? Never is a very long time. They can be made to last decades at sea level without yellowing. Properly clean would mean not exposing them to something that would attack the polymer. For example a window in a metal plating shop wouldn't last decades without yellowing.

I've only looked into bulletproof glass casually. Wikipedia has short summary http://en.wikipedia.org/wiki/Bullet_proof_glass. I was under the impression that bullet resistant glass put the glass on the external layer, as on Wikipedia. The glass layer can provide ample UV blocking. For architectural use where weight is unimportant, very thick layers of glass are used without plastic.

My understanding is that aquariums use glass not polycarbonate for two reasons. First, because algae and other marine life can both bond chemically to and erode polymers. Second, because plastics creep, that is they distort over time under a constant load. A plastic sided aquarium of more than trivial depth would gradually bulge until the sides popped out of the frame. Star Trek IV notwithstanding, I wouldn't expect to see it used for a big deep tank. For these two reasons I think the acrylics are only useful for small freshwater tanks for species that don't use sharp teeth on the tank.. the clear corners are nice though.

I should probably note that glass is a super-cooled liquid and will slowly flow over time, cathedral windows 3 or 4 centuries old are substantially thicker at the bottom than the top. Other materials in an aquarium will fail first.
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Post by evolutionmovement »

I've seen the effects of age on glass windows and drinking vessels in the 17th century houses around here - it's pretty cool.

Monterey Bay Aquarium uses acrylic in their exhibits. But, I was wondering more about keeping acrylic from aging as I plan on using it in a car I'm building and I wanted to know if the marketing claims about indefinite yellowing resistance from Modern Plastic were BS or not. I've seen many older aircraft with garbage acrylic windows, but they ARE old and maybe newer compositions would better resist aging. It doesn't need to last forever, but I would like the windows to last at least 10 years and look good.

There are several types of bullet resistant glass and polycarbonate is generally an outdated solution, but I thought maybe you'd have an idea of how they stood up over long-term light exposure.

I always thought Lexan was just a quality brand name for polycarbonate. It seems most plastics are differentiated, like metals, for the various formulations, but have only ever seen polycarbonate mentioned generically.

I appreciate the responses.
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Post by TrueBlue »

Great read, guys. Mine will probably receive some treatment shortly. Did we ever come up with a UV inhibitor, or was it just recommended to go with the 303 UV?
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Post by Legacy777 »

If you clear coat you shouldn't have to worry about it. Doug has the set of headlights I clear coated. I gave them to him a while back. As far as I know they're still looking nice and clear.

I've got another set of headlights, very yellow I want to do the clearing again.
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Post by Mattheww044 »

thanks for the post man, did this to mine and they look alot better, cant really tell the difference on the road though, but thats where the new lights come in :D
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Post by TrueBlue »

So, I bought the $15 dollar NAPA kit - 1000, 1500, 200, and 2500 grit papers, plus rubbing compound, cloth, and rubber gloves. Divided everything in two and set to work.

Two hours later I was staring at lights that could have easily passed for glass lamps. Trick for me was to keep the lights saturated with warm watre - one hand scrubbed, the other hand sprayed warm water from a Windex bottle. Absolutely amazing results.
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Post by Hyena »

I used a kit designed for cleaning aircraft windshields. its a three part system, you attach this buffing pad to a cordless drill. (its kinda like an insanely fine sandpaper) and you apply different liquids that are coarse to less course and buff with those. the kit is not cheap by any means at about $70 but its enough to clean two windshields... so about 40 headlights if not maybe some more. (I'll try and post a link to it later)

but these are the results. before and after. on my 1993 L AWD Wagon (the one with the roof rack)

truly some of the most yellowed legacy lamps I've seen

Image

and after

Image

Image
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Post by Tommio RS »

Ok. Here is the stuff i used on my 93 leggy turbo.

Its name is "Power Cut Plus"

Link:

http://www.automagic.biz/compounds.htm

Its the bottem one.

I work as a detailer for Subaru and i use this stuff for ALL the used cars with yellowed head lights. The product itself feels like your going to cut your lens but the more you use the better it works. After awhile of rubbing or buffing the stuff will INSTANTLY turn in a sort of polish/wax and wax your head lights!

Aswell another thing ill note about this Power Cut Plus. It is very very hard on paint. the site says its paint safe....But i sure dont think so!

Another product that works great to remove dead bugs, stuck on crud on windows or just remove those really ugly little white scratches is GS-1

Link:

http://www.automagic.biz/polishes.htm

Yes the GS-1 could probably be used to buff your headlights but not to the same effect as Power cut tho.

These products are not going to get your headlights perfect! They will get dam close tho!

And really in the end all you need is a real hard core scratch remover and some elbow grease.

Ill post some pic of me car in a bit.

Coool!
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Post by TrueBlue »

Here's an update to my earlier post.

I used the NAPA kit, and obviously, without any sort of UV inhibitor, the lenses made it only a short period of time before they started to fade again.

I was turned onto a product on another forum and gave it a shot. DCX products are infamous for having fogged out lamps... below is my x-post. Product is called Crystal View (http://www.myheadlight.com/)
So - used the Crystal View product last night. Took a few minutes to find it, it was behind the counter at my Advance Auto Parts. Cost $20, and I picked up some 600 grit (as previously mentioned, the Turtle Wax kit was not abrasive enough to take down the hazing.)

Wow. I've done three sets of lamps with three different kits, and this one far and away was the best. Same initial results as my NAPA kit, but much quicker and likely with longer lasting results due to the inhibitors.

I wet sanded with a spray bottle of hot water and mild dish detergent with 600 grit L to R (5 mins), then the included brown paper (felt like 1000 grit) T to B (3 mins) then the blue finish (probably 1200-1500 grit) at 45° angles (3 mins).

It comes with a rubbing compound, but I used Meguiar's Plast-X. Rub until dry, buff haze.

What makes the product so good is the second compound, which is more than just a sealer - it actually contains an acetate or similar component which seems to "liquifiy" the very top layer of lens, so that when it evaporates, it leaves a very "wet-look", clear result. This is the part of the product that other kits do not have and what make this product the best I've used so far.

I spent about 30 mins on each lamp, you could probably get away with 15 or so.

Cellphone pic:
Image

Cliffs: $20 and 1 hour gave me results that should last a long time.
Package looks like this:

Image
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Post by Suigintou »

I've used that crystalview stuff on 2 cars now and it works good. The only problem is you gotta sand it with your hand which can either go really well or really meh.

The polish/sealer combo does last a long time though. On the first car I used it on its still clear 3 months later.
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Post by kimokalihi »

Hopefully it lasts more than 3 months.
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Re: Polymer chemistry is a little complex for this forum....

Post by brand »

polychrome wrote:I should probably note that glass is a super-cooled liquid and will slowly flow over time, cathedral windows 3 or 4 centuries old are substantially thicker at the bottom than the top. Other materials in an aquarium will fail first.
This is a persistent myth with basically no empirical evidence. It's a scientific urban legend. Glass is not a liquid, it has properties analogous to liquids but flowing is not one of them. There are numerous sources to support this if you run a google search, but I'll throw one out to start: http://www.cmog.org/dynamic.aspx?id=294
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Post by Smithcraft »

Since I can't afford to get some JDM/EDM housings for a while, I'm certainly interested in what I can do to improve my headlights.

So, here are some other options from the Lincoln forum I used to frequent.

One member used a product called ClearJet. He used it in 2006, and when asked about how it's looking now, he said:
After a close inspection, I am starting to see where the coating is chipped off, but there is still 99.9% coverage. The only way I really knew the coating was still there was that I accidently scraped a tiny bit off with my newly cut fingernails...so that's a good sign. The largest chip measured 1/8" x 1/4". The underlying plastic was flawless, so it must have just happened. The chipped area was not yellow, unlike the coated area which has yellowed slightly, like a typical 5 year old headlight, which means the coating took the brunt of the UV light. It should be noted that this coat is a couple years old, so I've exceeded the manufacturer's recommended specs (I think they recommend a yearly reapplication), and it shows. It does need to be cleaned off, prepped, and recoated.

All in all, I would say that using this stuff is marginally better than not using it at all simply because it requires the same or more amount of work as just sanding the headlight every couple years. I've decided to keep using the coating simply because it keeps UV light from the lens - the impact resistance is neither here nor there...you've got to sand it off anyway.

The overall best solution is a plastic cling film like Lamin-x. It is invincible to impact and UV light (won't chip or discolor) for 5 years. But my local dealer quoted parts and installation at $300 for the Mark, so it aint cheap. I'll continue to coat until something better comes along.
His original application post from late 2006 -
I found a product called ClearJet that is both a UV and abrasive protectant. It comes in a 12 oz. spray can and costs about $12. The product description says it is made to protect vehicle graphics (among other things) such as decals and stickers. Safe for almost all surfaces. Anyway, I bought a can and applied it to my fairly new headlamps. It's easy to use, though it likes to run so we propped up the headlight in a horizontal position for a few minutes. I couldn't have imagined such excellent results. It actually made the lamp look BETTER than new. It now looks like it is made of crystal. We'll see how it holds up. This may be the headlamp "Holy Grail" we've all been looking for.
Which leads into Lamin-X. I'm not sure what his local dealer was smoking as two sheets big enough for the Mark VIII headlights are $60(total package). The above linked sheets which are a bit big for the Legacy headlights are a bit over $40 for the kit. Installation videos.

Finally, I'll mention Xpel. I'm not sure if anyone has used it(here or there), but it has been mentioned. From reading the description, it seems to be designed to protect the lense from damage, more than UV light. Xpel runs for about 13 cents per square inch.

Hopefully, these options will be of some use.

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Post by Bdub »

I purchased the 3M headlight cleaning kit. Comes with a drill adapter, which you use for sanding, wet sanding, and buffing, along with a few very fine grit pads for it.
Simply amazing. I thought my headlights weren't that bad, but once I finished one and took a step, back I was like :shock: . I also did the marker lights, which did a great job as well.

I originally bought these for my mom's 01 Sebring, because her headlights are so yellowed, she can barely see at night. Figured I'd test it out on my car first, glad I did!

One kit will do 2 cars by the looks of it. 2 headlights, the bottom marker lights on my 91, and 2 headlights on the Sebring. Not bad for $20.
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Re: How to get rid of the yellowed headlights

Post by brand »

I used the 3M kit yesterday on the 91. I did the headlights and the blinker covers (these are easy since you can just unscrew them and set them on the floor). Did an awesome job. Probably took me an hour and a half. Take your time and do some extra sanding on each step and you'll be rewarded. I didn't do quite as much sanding on the second headlight because I thought I'd done enough, and the first headlight I did looks noticeably clearer.
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Re: How to get rid of the yellowed headlights

Post by Mikerthebiker »

Grabbed a Turtle Wax headlight restoration kit today, cost about 10 bucks, and have no regrets!

before:
Image

So gross and yellow.

after compund
Image

box claims that this may be enough for some headlight, i decided to use the sandpaper because i figured it would be worth while.

after sanding and compund:
Image

also comes with a "sealant wipe", but am still thinking of snagging a can of clear coat from work to spray em. these definetly look alot better in person, glare doesnt really do the kit justice

looks alot nicer with out the yellowing!:
Image
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Re: How to get rid of the yellowed headlights

Post by Danny-G »

i did a seemingly simple version of what ive seen here, sanded the headlights down with 150 grit paper, wipe clean, spray with rustolum clear coat and looks great to me. i did this a few months ago and not even a noticable haze yet, i have some after pictures
Image
Image
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Re: How to get rid of the yellowed headlights

Post by SubyFusion »

Did mine! used 400, 600, 800 and 1000 grit wet sand paper. wet sanded the crap out of um :-D (Don't forget the soap when wet sanding, other wise its a pain!) then I get some rubbing compound, put in on a buffer and got rid of all the remaining scratches from the sand paper. Then buffed again with plastic polish. Works great its been about 4 months now and haven't had any problems. I didn't clear coat them instead I just wax them every time I do the car and it keeps the yellow away :D
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Re: How to get rid of the yellowed headlights

Post by Jester808 »

What a difference :D. I used just what I had around the garage, 600-grit to 1000-grit wet-sanded with the water hose outside, then a polishing with Turtle Wax's light polishing compound and an electric polisher.

Just after wet-sanding the drivers side:

Image

After:

Image

Image
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