Headlight grunge

Is it possible to get a headlight lens that has yellowed on the inside
clean? Just curious.

 

There some products on the market that claim to be able to remove the
yellowing from headlight lenses. You apply them and lightly buff the
plastic to remove it. I'm more reserved to the fact, upon noticing many
vehicles from the past 15 years with this problem, that replacement may
be a better viable option. You can usually get replacements for most
vehicles fairly inexpensively on eBay. The sun's UV rays deteriorate
the plastic and will continue to do so until better UV protection can
be designed into the plastic. Probably, in the future, plastic
headlight lenses may be considered "normal wear items" that may need
replacement sometime in their lifespan due to UV damage, similar to the
way we replace tires and spark plug.

 

You can certainly clean the crud that's developed in there over the
years; it's similar to a bottle washing operation, so you have to remove
the headlight assembly from the car to do it. As far as exterior
yellowing goes, waxing the headlight lenses at least once a year along
with the rest of the car will prevent most of it from ever happening.

 

As for the outside at least uyou can use number 1200 black sandpaper wet.
That does the trick. The headlites comes back cristal clear like new. But go
slow as not to burn the plastic. Good luck.
L.G.R.

 

Hi...

Respectfully suggest that you'll do much better finishing up with
2000 grip paper - and even then they'll be very hazy until you
wax them or even better give them a coat of clear coat.

Take care.

Ken

 

Something we had in the past with those very functional glass sealed
beam head lamps.

 

Not only are there plastic polishes out there that go from fine to extremely
fine, there are even kits sold (usually by restoration supply places) for
doing exactly what you want...

 

You will probably find the the grunge is actually a surface phenomenon
on the *outside* of the headlight. People have a lot of success with
using sandpaper of successively finer grits, starting with 800 or 1000,
depending on how thick/coarse the grunge is, and working your way to
2000 or 2500, and engine with polish, like Meguiar's PlastX.

Be aware that you will be removing (sanding thru) a "protective,
UV-resistant" layer of plastic on the surface, which ironically is the
material that broke down under UV light and oxidation. You will need to
periodically (every few weeks) polish the surface again to maintain the
clarity of the renewed surface.

If you want to not have to periodically polish them, then, afer
polishing, chemically remove the polish and spray with clear coat -
that's essentially what they had on them from the factory.

There are some kits in WalMart - about $20 IIRC - for doing the sdame
thing. They take more time and elbow grease than the package hype lead
you to believe. They come with a wipe-on clear coat.

Here's a recent thread on the 300M Club forums to show you that cleaning
them up is very doable using either the kits or purchasing the sandpaper
and polish separately, and the results are pretty impressive:
http://300mclub.org/forums/viewtopic.php?t=15153&highlight=headlight

Scroll down to look at the photos of the results obtained by several people.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Right on, Ken!

Take a look at the results some people got in this thread on the 300M
Club forums (scroll down to see 'before' and 'after' photos):
http://300mclub.org/forums/viewtopic.php?t=15153&highlight=headlight

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Glas can be moulded into the same shape as the plastic headlight lenses.
This nonsense with the plastic lenses is a cost-saving thing.

Ted

 

This thing with the plastic (Lexan) headlight lenses is something Ford
cooked up (1st car was an '84 Lincoln Mark VII) to enhance safety
(shatterproof), reduce weight (not much), improve fuel mileage (hardly
measurable) due to ‘Aero’ design, and allow headlight changing with zero
tools. Ford lied to DOT/NHTSA about the need for maintenance to get
approval for these lights, saying that fighter plane canopies were made
of the same stuff, and while true, they DIDN'T tell the feds that the
military changed out those canopies for new on a 12~18 month maintenance
basis. The replaceable 9004 bulb that went into the headlight fixture
was also the most terribly (non) designed bulb ever made, leaving the
driver with a choice of a big black hole in front of the car to be able
to see down the road, or lots of foreground light but very little
distance lighting, depending on aim. big business for "foglight" makers.

 

Chrysler also used some plastic sealed beam headlights as OEM in the
1990s. They got cloudy too, but you just replaced them with glass
units. I think Sylvania build them?

Beam pattern is not specifically related to the 9004 bulb itself but the
REFLECTOR the bulb works with. It doesn't matter if the headlight is a
sealed beam, composite unit, projector beam, or HID, if the beam pattern
is not good (or as good as the Euro-spec lights with normal bulbs, even
semi-sealed beams!), then you can't see at night . . . even with 100
watt bulbs (which have been known to melt the plastic housings they fit
into).

If you look at the "crystal lens" headlights on the new GM full size
pickups, the lens is "invisible" and will probably stay that way for a
long time.

Personally, I'm not in favor of using sandpaper on plastic to get it
cleaned up. You might use it for the first "attacks", but using a
compound/foam buffer item would probably be a better deal. In the
Reatta forum, somebody mentioned using a Shell AeroShield polish to
remove the haze from the Reatta tail light panel. Seems several posters
had used that product with good results.

I do concur that any work needs to be done on the outside of the
composite housing. There might be some accumulation on the inside of
the lens, but most of the issues will be on the outside where "the
elements" (and bugs) have deteriorated the finish on the lens.

Just some thoughts,

C-BODY

 

Indeed, I have only seen it suggested for the initial cleaning up,
followed by polish (to fill in the flat-looking microscopic surface
finish) *or*, for maintenance free surface at least for a few years,
clear coating the surface after the sanding, polishing, and chemical
removal of the polish residue.

When that factory clear coat layer deteriorates like it often does, only
the aggressive behavior of relatively coarse grit sandpaper (followed by
successively finer grades) is going to get down to plastic that is free
of crazing and haze.

For your consideration - and *your* enjoyment:
http://300mclub.org/forums/viewtopic.php?t=14691&highlight=sandpaper+clear
(lots of photos, so give the thread time to download)

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')