3M headlight lense restoration

[Soundguy]

one more question.

As I mentioned earlier.. I have seen some 'scratch repair' fluids that are nothing more than a paint on clear coat. anyone know where they are for sale? I could use some of that for some non tractor / lamp applications I have. ( face mask and some paintball headgear that has a few scratches. repalcement lenses are 50$.. if I can scratch repair them with something that is optical quality.. would be nice..

soundguy

 

[crazyal]

I bought a kit from Autozone, think it's made by RainX. It has three different grit sanding pads and two different solutions. The first step is to clean the headlamp with glass cleaner. The next steps are to use the sanding pads with the first liquid (I think it's just glass cleaner). The final step is to use the other liquid, not sure what it is but it's pretty heavy and fills in any fine scratch marks that were left from the sanding pads.

Over all it works pretty good. The second liquid works great. Once you put it on the plastic is crystal clear. I thought rain would wash it off but it's been 6 months now and it still looks great. Even if from now on once a year I have to redo the headlights then that's a small price to pay. Plus there's enough of the second liquid left to do 10 or more headlights. I think I paid in the mid teens for the kit.

 

[Soundguy]

the 2nd liquid must be some kind of thin clear coat crack filler.

bet it would be a great surface treatment for the 3m kit that uses rubbing compound as it's last step.. .. IE.. a sealer afterwards..

soundguy

 

[Lt CHEG]

There are really two issues at play here.
1. The surface is pitted, eroded, oxidized, etc and the kits fix that by re-smoothing the lens.
2. The lens is not quite what you think it is.

Let me explain. Almost all of the plastic headlight lenses are made from polycarbonate as it is very strong, super tough, can take the temperatures of a headlight, and is quite optically clear. It has a couple weaknesses as a lens material: it does not hold up to just about any solvent, and it scratches very easily.

There is a solution for this: They Hardcoat the PC lenses after molding to improve both of those weaknesses dramatically. It is a common siloxane-based coating (glass-like, is a simple way to put it) but it is thin and can be brittle to some degree.

So when you refinish a lens, you are basically buffing off this coating and any other surface defects. This is why the lens will likely not hold up in the long term. Unfortunately I do not know of any aftermarket hard coats as the original requires a precise coating and then an oven drying procedure.

Just so you know. Something like a hard carnuba wax, as one poster recommended, may help extend the life, but once the surface degrades that much you are in a cycle of wash, rinse repeat. But of course by the time you do this, the vehicle is already pretty old so it may not become a big issue for the remaining life.

Here, I found one for you:
http://www.momentive.com/momentiveI...les/Documents/Data Sheets/SHC5020 MB.indd.pdf

I used to work at the plant that made the coating. It used to be owned by General Electric but was sold to a capital management firm which ended up calling the company Momentive. I did a co-op there as a production engineer and it was a great gig. I didn't work directly with the sealant mentioned in the above post, but as memory serves me that coating and paper release (the slippery stuff on the paper which you peel stickers off of) were two of the most profitable products produced by the plant. That same plant still makes the GE branded caulk that you buy at your local hardware store. Even though it is branded "GE" General Electric has divested itself of the production.

 

[Kyle_in_Tex]

There is a magic chemical that can really clear up a freshly sanded (600grit or higher) Polycarbonate. It is very dangerous and a very strong VOC. I don't recommend it to anyone unless they are properly clothed and protected and done in a venthood. You have to wear neoprene gloves as it can penetrate most everything else. It is dimethylene chloride. It will smooth over PC like glass if you know what you're doing. The process is called vapor polishing. We do it at work on some optical grade lab parts we make. PS, it only takes a second to clear up the PC, after that, it starts melting. Metal, glass and teflon are the primary methods of containing the stuff.

 

[kebo]

I'm posting this here as good headlamps are a good part of towing..

I had slight yellowing or frosting of the plastic lamp covers on . well.. most of our vehicles. I decided to try the 18$ system 3m sells.. grabbed the kit at walmart.. a guy on the isle saw me pick it up.. said he used it.. works good.. but told me to go ahead and pick up a 6$ bottle of their 3m rubbing compound ont he shelf under it, as the lil 1oz packet they give you in the kit is about good for 2 small car lamps.. aor 1 big truck lamp

got home.. figured what the heck.. read the directions.. did the prep, cleaning and masking tabpe to protect all the other surfaces. used my 450 as the test case.

WOW.. works great... dern near almost crystal clear. now my 350 and 450 have good lamps. plan on doing the wifes yukon as well.. heck.. might even do the old beater dodge before i sell it..

worth the incestment if yo have frosted lenses.. and DO get the lil extra bottle of compound.. a variable speed 3/8 chuck drill is what you need. takes a good bit of swirling.. so i don't reccomend a battery powered on.. use a corded one.

and DO use 2 layers of tape as the instructions suggest.. not just a single layer.

soundguy

I used the very same kit on my F150 with very good results. The lenses on these trucks (2000 models anyway) are not crystal clear (when new) like most of the newer vehicles are, but the 3M kit cleaned them up as good as they can get. It cut right through the crusty oxidation and yellowing on the surface, then the polishing step got them smooth and clear. You can see the difference at night too! Definitely recommend the 3M kit.

 

[Soundguy]

yep.. both my 99's and 2000 are 'crystylized insides', not the clear/clear like some of the newer ones.

soundguy

 

[buck12]

Has anyone tried any of the stick on protective films for head lights such as those sold by Wheather Tech?

 

[Diamondpilot]

Has anyone tried any of the stick on protective films for head lights such as those sold by Wheather Tech?

We use them on airplanes but its a whole different set of issues moving at 525mph.:laughing:

Chris

 

[buck12]

We use them on airplanes but its a whole different set of issues moving at 525mph.:laughing:

Chris

I was thinking of giving the protective film a try on my wife's new Explorer. The head lights on her last car looked terrible. I tried the restorer available at Wally world. It made them look better for a couple of months then the cloudy look returned. I would like to avoid that with the new car.