My Journey into Headlight Restoration

After having restored close to 10 sets of headlights and trying out new techniques from hand sanding to machine sanding and finally the recent spray on hard UV coat, I can now conclude my journey of headlight restoration.

Everytime my friends ask me this, “Hey, do you know where can I buy that liquid that can make my yellow headlights look super clear? I’ve heard of my other friend buying it and no hard rubbing was needed to restore the shine.”

I keep wondering if there IS such a product but I often tell that there is no shortcut, miracle product for headlight restoration, well depending on the condition of the headlight that is.

There are basically TWO types of damages, on the coating of the plastic or within the plastic itself. If it is oxidation, yellowing is on the coating of the plastic, chances are machine polishing alone will be able to restore clarity up to 90%, no sanding will be needed.

But when defects has damaged the plastic beneath the coating, sanding is needed.

Let’s start off with the easier way, polishing by hand.

My good friend Chris a.k.a Izso wrote an interesting article featuring yours truly. We compared using Autosol, Meguiar’s PlastX and toothpaste in removing yellowing from headlights, it’s an entertaining article, link below:

http://www.zerotohundred.com/newforums/features/405905-mythbuster-does-it-work-headlamp-cleaning-the-conventional-way.html

So now that you know that even toothpaste can work a fair bit, then you might wonder why bother with sandpaper at all?

The damage of the Perodua Myvi’s headlamp was clearly on the coating as there was no micro cracks or blisters when looked closely. So hand polishing was more than enough to return a satisfying outcome.

But what if hand polishing isn’t enough? I’ve listed my machine polishing steps below (with some very light sanding).

Here we have a headlight which belongs on a Toyota Alphard. There is slight yellowing on top and also micro cracking, but the rest of the headlight was in great condition. So in this situation, I deem it as unworthy to pull out the sandpaper and stick with machine polishing.

Steps:

1) Light sanding with Mirka Abralon 2000 grit with rotary
2) Compound with M105 and spot wool pad
3) Polish with M105 and spot white polishing pad
4) Finish with M205 and spot black finishing pad
5) IPA wipedown
6) Coat with Gtechniq C1

As you can see, the products are pretty good for something that only took me about 20 minutes. If you look closely there were some micro cracks that couldn’t be removed, it required sanding but as mentioned, I felt that it didn’t need it.

Question: Why don’t I just sand the top half then?
Answer: While I had a regular customer handing me BMW headlights to restore, I realized that the coating on the plastic is slightly tinted. I’m not sure if this only applies to BMW headlights only but I assume it applies to most headlights. The headlights they handed me to restore was in near perfect condition except for an odd deep scratch. It made the headlight unsellable. So I tried to do a spot repair and realized there was a colour difference, the coating that I removed made the plastic look less dark. So I had to sand off the whole headlight just because of one small scratch (lots of frustration when you thought that you can just do a small spot repair and call it a day). Example below:

The bug splatters were easily removable but the deep scratch made me worked the headlamp like hell.

Sanding grits used were:
400 -> 600 -> 800 -> 1200 -> 1500 -> 2000 -> Mirka Abralon 2000 -> Mirka Abralon 4000

Compounded and polished with:
Osren P40 with wool pad -> Meguiar’s #105 with wool pad -> Meguiar’s #105 with polishing pad -> Meguiar’s #205 with finishing pad

This process was long and tiresome, it took me roughly 3 hours for ONE headlight, but I could get it into an almost new condition.

The sander I’m using is a finishing sander that orbits at 10,000 OPMs. It uses 1/6 sheet sandpaper which you just cut yourself.

The deep scratch you see above had to be re-sanded. No amount of compounding or fine sanding will remove it. I worked from 600 grit upwards to remove that scratch.

It looked good enough under natural lighting, but it wasn’t perfect in the sense that there were still swirls left from the machine polishing process.

Question: Why start from such a rough grit, 400 and not a finer grit like 1500?
Answer: I learned that the factory coatings on headlight are very hard and very thick!! 1500 grit will take you a super long time to sand through. Even 1000 grit will be tremendously slow, then I learned 400 may be too rough. Now I recommend to start with 600 instead.

Question: When you said it wasn’t perfect because it had swirls, can’t you correct it as you would on paint?
Answer: When the coating is removed and you are working with BARE plastic, it is very sensitive. Imagine hard German clearcoats vs super soft and sensitive Japanese clearcoats. I find it impossible to finish down swirl free on bare plastic and I still can’t, hence it is not as perfect as it can be.

Another example of a headlight with lots of stone chips. Same process as above:

No more stone chips.

Both headlights done:

At this point, my customer, a spare parts supplier could then resell these as “used”. The headlight with lots of stone chips which basically means high mileage is now showing that it is barely even used.

But I was still unsatisfied with the result in two ways:

1) Unable to finish down bare plastic perfectly
2) Taking too damn long, 6 hours for a pair of headlights.

I clearly remembered this comment by Martin.

“I think you waste too much time doing this headlights, the process was just too long and old fashioned. No coating can last longer than the original factory uv coating to protect the headlights more than 1year. I can do it with 3step only, 1st step – an orbital sander using 320,600 and 1200grit and water. 2nd – step spray uv coating 3rd step – cure with uv lights and tada! finished. 30minutes only. that exclude the prep work time. I can give warranty 1 year but actually it can last 2 – 4 years.”

It was posted in the comment section of this post:
https://wetshine.net/2011/08/17/headlight-restoration-bmw-520/

I was astounded that when he mentioned he could do it in 30 minutes. I searched for this product high and low and found one product made by Glasweld. It’s called G Clear Hard UV Coat, the distributor is in Singapore and I planned a trip down there to get it, among other things (cheaper M105 and M205!!). I went down with Henry from Osren and it was pretty much a detailing trip, catching up with detailing friends, visiting detailing shops, etc.

So I recently tried out this UV hard coat and set out a goal to achieve that 30 minutes record time.

Look at the photo below and compare to the ones above, what difference can you spot?
The one below has stone chips while the one above does not have any. This shows that the previous technician has attempted to restore the headlamps on one side and probably realized he couldn’t get it to a satisfactory level, so he stopped working on the other side. There were leftover sanding marks and they did not even fully sand off the factory coating. You can see uneven yellowing of the headlight pictures above.

Firstly I mask with a layer of masking tape and then two layers of duct tape. I found out that this process has already taken up almost half of my 30 mins time-frame. So I decided not to race against the clock and just focused on getting it right since it was my first time with this system.

I machine sanded with 600, 800 and 1200 grit.

Tight corners were hand sanded.

I then masked up the surrounding areas and wipedown the headlight with IPA and lint free window microfibre cloth.

Holy cow this product is AMAZING!!!

but……

as always in detailing, skill and technique is ALWAYS more important than product!

If you look near the reflection of the sunlight, you could see the sanding marks. This can be improved by using an interface (thanks Dan from glass-fix.net for the advice), or a spot sander that uses foam sanding discs (Mirka Abralon style).

In the picture above, you can see runs in the coating. Due to my nervous state, I forgot if it was because I sprayed on too much or too little in that area.

The other headlight turned out much better, with only contaminants being on the inside.

The excess coating that has dripped to the bottom of the headlight and hardened.

That photo was about 30 mins after the spray, the excess coating felt rubbery and definitely not hard yet. Even after 1 full day, the headlights had a bit of a tacky feel to it but was dry to touch. After 1 week, it felt completely hard.

1 downside to spraying in an uncontrolled environment is the exposure to airborne contaminants. Dust landed on the surface after spraying and it has stuck onto it while it dried.

Another flaw I remembered when I saw the work sample while I was at their office in Singapore was the amount of heavy orange peel left behind.

Compare the two reflections below:

The first one has more orange peel than the second one. I’m also not sure if this was due to the curvature of the lens or the spraying method. I will try to lightly sand and compound to see if I can remove the runs and orange peel soon.

All in all, I’m quite happy with this result and I managed to finish both headlights in less than one and a half hours.

THE BIG CONCLUSION:

Polishing vs sanding, it depends on you or your customer’s needs. Assess the damage of the lens, if it’s yellowing on the surface, just polish.

If there are stone chips, sanding is a must.

Tools to use? In an ideal world, a 3″ air driven sander with foam sanding discs are great. They will get into small places easier, the smaller tool provides better handling and the foam discs will leave shallower pigtails, easing removal during the following steps. Downside is the high initial setup cost.

UV Coat vs Polishing. I’d say UV coat for sure. You might say it is expensive. Yes it costs me 95 SGD (Singapore Dollars) for one can, which is sufficient for 10 pairs of headlight (20 individual headlights). That averages to 9.5 SGD or 24 MYR or 7.5 USD or 4.8 GBP per pair of headlights. It saved me four and a half hours, I think the cost is well justified. The only downside is that you need a controlled environment, such as indoor space with no wind, and because it is indoors, you need to use their UV curing lights which has specific wavelengths to cure the coating, WHICH is also mighty expensive. But those are just initial costs, if you do this full time, I’m sure you can recuperate the costs quickly.

In a perfectionist’s world, it would be sanding, UV coat, leave for 1 week for complete curing, light sanding and compound to remove orange peeling.

All in all, headlight restoration is a tedious and slow job, if you want really good results. I’ve learned a lot and still have lots to improve on headlights restoration, but feel comfortable to say I can restore headlights pretty well now, albeit at a slower pace.

With that done, what should my next journey be? Window tinting? Glass crack repair? Paint protection films? Paintless dent removal? The amount of things to explore and learn is countless!

Until next time guys. Enjoy the weekend and happy detailing!!